Many would wonder why anyone would want to modify such a well-proven package like the Stealth Bomber or the Stealth Fighter and I suppose the simple answer is “because we can”. In my case I wanted to differentiate both my Bomber and Fighter from the standard offering, but in two completely different ways. In the case of the Bomber, the project was all about in your face grunt and speed…however with the Fighter, modifications were practically the inverse and they were all about making the E-bike as light and nimble as possible. Both E-bikes relied on the installation of Lithium Polymer batteries (LiPo) and custom controllers to achieve the desired results. Read on to see how these two very different objectives were reached.

Stealth Bomber modification and customization

My Stealth Bomber is the Mk-1 model and has a slightly bulkier frame then the current model. The Mk-1 Bomber was designed for Headway 10-Ah cylindrical cells, and as such it’s both wider and deeper in the battery compartment. In addition to this, it was built with a heavier gauge Cro-moly skin making this E-bike a few lbs. heaver than the current model. My Bomber also came with the higher torque (but lower speed) 5405 motor. This motor is good for around 37-MPH (60-kph) on the standard 80V setup.

My aim with this E-bike was to reduce its weight to around the same as the current model, but at the same time significantly increase the E-bike’s speed and acceleration. To achieve this, it meant the voltage needed a substantial increase, and as such both the battery pack and the controller would need to be replaced. My target speed was around 50-MPH but to achieve this with the high torque 5405 motor meant I needed to run around 120V.

Batteries

The first modification was to remove the stock Headway battery pack and replace it with some energy dense LiPo packs.  After some careful measurement, I found I could comfortably fit in fifteen of the 6S 5000-mAh Turnigy packs, and still have enough room for various plugs and fittings. The fifteen pack configuration was perfect for what I had planned, and meant I could arrange the packs into three groups of five. Each group were series-connected to create three separate 125V packs.

These grouped packs were then paralleled to create a 30S/3P configuration for a theoretical 1500-Whrs of total capacity. Packs were purchased from HobbyKing for a total cost of $850 landed, a cost basically covered by the sale of the second-hand Headway pack. It should be noted that the latest batteries used in the Stealth product are only slightly heavier then LiPo’s of the same capacity but with the added bonus of being fully protected by a BMS and completely safe to use.

Turnigy 6S / 5-Ah LiPo Battery packs arranged into 3 x 125V modules. A parallel wiring harness is then used to tie all 3 modules into a 30S/3P 1500 W/hr pack. Safe usable capacity is 1250W/hrs

Packs installed within the E-bike’s battery compartment.

Controller

The stock controller, although a robust high powered unit, could not handle the higher voltage without some major modification.  Rather than going through the process of changing out all the voltage sensitive parts such as FETs and capacitors, I opted to purchase a new Lyen 18-FET highway-edition speed controller. These controllers use an Infineon-based board but are then hand-assembled with high quality high-voltage componentry together with all the required connectors such as direct plug in Cycle Analyst, re-gen, ebrake, 3 speed switch and programming port.

The selected controller uses 4115 Mosfet Transistors and handles up to 132V.  However, the controller is setup for a 40A maximum output and as such still needs some modification to get some serious power out of them.  In this case my target power output was 80A. For the controller to stay reliable under these conditions modifications were definitely required. These included beefed up main current carrying traces, modifications to the current measuring shunt and upgrade of both battery and phase cables from 12-gauge to the fatter 10-gauge silicone cable. Custom programming was then required to setup the controller to suit.

Above you see the back side of the controller showing beefed up traces soldered by hand.

Software interface for programing custom parameters into the controller

Next step was to move the controller from the stock position under the front of the E-bike and mount it internally within the battery compartment. The controller was removed from its case and the controller heat-sink attached directly to the E-bike frame. By doing this, the frame now becomes a gigantic heat sink for the controller, allowing even better power handling performance. The removal of the controller from the outside also gives the E-bike a cleaner look, while at the same time fully protecting the controller from the elements.

Screws used to hold the controller heat sink in place. A layer of heat transfer paste was applied between the heat sink and E-bike frame to ensure the best possible heat dissipation.

Controller installed complete with protective cover over the delicate components.

Smoother overall lines without the externally mounted controller

External Battery Isolation

When running LiPo packs, I think it is of paramount importance to ensure the battery pack can be fully isolated from the controller without removing the side covers. To achieve this, an external loop cable system was installed from the battery to the controller.  This loop cable is external to the E-bike and unplugs in just a second, should the need arise. It also becomes both a bulk charging point and an auxiliary pack connection point. My connector of choice for this duty is the EC5. These plugs are typically used in high powered electric model aircraft however they make an excellent plug choice for high powered electric bikes also.

Top plug goes directly to the controller. An external auxiliary pack can be connected here if required. The lower plug goes directly to the battery and doubles as the charging point for the E-bike.

Loop cable attached. Doubles as an emergency quick disconnect battery isolation plug.

Bulk Charging

Bulk charging is a method of charging that’s used to charge the entire pack as one high-voltage unit, as opposed to splitting the pack down into smaller groups for balance charging. In this case I used a 900W LiFePO4 from BMS-Battery, that is set up to cut out at 125V.  This is a really quick and convenient way to charge LiPo’s however you need to be aware of the risks involved and take the necessary precautions to protect both yourself and property. These precautions are a subject all on their own, and as such I won’t go into detail in this review however it is extremely important that anyone attempting to use LiPo chemistry on an E-bike fully understand what they are getting in to.

900W charger from BMS Battery. This charges the battery pack in around 2 hours

3-speed switch

Having a 3-speed switch is nothing new to the E-biking community, however I think it is one of the most under rated accessories out there. On high-powered setups such as this E-bike, they make a huge difference to the E-bike’s ride-ability. Having 10-kW on tap means that the throttle becomes very touchy, and for someone who hasn’t ridden the E-bike before…its downright dangerous. I have speed-1 setup for around 22-MPH (35-kph), speed-2 around 34-MPH (55-kph) and speed-3 is unlimited and around 53-MPH (85-kph). On speed-1, the E-bike is very well mannered and basically idiot proof. Speed-2 accelerates at a similar rate to a stock Bomber but tops out earlier. Speed-3 is an absolute blast. With 10-kW on tap, the front wheel comes up very easily and acceleration is nothing short of brutal, even at upper end of the speed envelope. Acceleration is around zero to 45-MPH (72-kph) in 5 seconds.  This is quicker than most cars and even gives small motorbikes a bit of a scare.

Easily accessible 3-speed switch

Video depicting the awesome acceleration of the Stealth Bomber.

Other less obvious modifications are the replacement of the stock 16-tooth freewheel to a 14-tooth freewheel and the addition of a type of seat post where the rider can adjust the height while riding.

The 14-tooth freewheel allows you to still pedal at a comfortable cadence, even when traveling at 38-MPH (60-kph). Some would argue…what is the point of pedalling at these high speeds? The truth is, as a percentage, you are going to be contributing very little to the overall power required. However, being able to pedal gives you the ability to still get some exercise even when riding at high speeds. Personally it just feels wrong not to be pedaling with some meaningful input, no matter what the speed.

The adjustable seat post gives you the ability to adjust you seat height on the fly. This is particularly useful on E-bikes with big suspension travel. The Bomber has a massive 250mm travel at the rear and a total 14” clearance from the ground to the bottom bracket.  This means that if you want to have the correct leg extension while pedalling, you can only just touch the ground with your toes. This is fine for commuting, but when out in the dirt, you want to be low enough to easily drag a foot if you need too.  Having the adjustable seat post gives you the ability to quickly change to suit the conditions. As a tall guy, with long legs, I have found this addition to be particularly useful.

Stealth Bomber Summary

Although the Stealth Bomber is a great product out of the box, it also makes an excellent candidate for higher performance modifications. This is due to its extremely robust construction, high speed handling capabilities, and strong braking performance.  The Mk-1 Bomber, dare I say it, is an even better candidate for modification than the latest model. I say this because firstly, it is out of warranty so you don’t feel guilty about making changes to it. Secondly, it has a larger battery compartment and uses thicker materials for the frame than the current model. Not to say the current model is under-engineered, it’s more that the Mk-1 model was perhaps a little over-engineered. Perfectly understandable for a new product offering a lifetime warranty on the frame and swing arm.

With the modifications now complete, total weight has been reduced to just under the weight of the standard Bomber, tipping the scales at only 51 kg (112-lb) Power has been effectively doubled over the stock setup, and the overall look is improved with the relocation of the controller. Range is similar to the stock Bomber if ridden conservatively, but spirited riding will certainly reduce you overall range quickly.

Kepler-modified Bomber Completed

Stealth Fighter modification and customization

The Stealth Fighter project was a completely different proposition to the Stealth Bomber Project. Firstly, my Bomber was essentially out of its warranty period and as such I had a free rein to basically do what ever I wanted. The Fighter was quite a different proposition. This project started with a brand new frame from the Stealth Factory. Stealth Bikes do not sell frames to the general public, however…my long time association with the company gave me enough leverage to convince management to sell me a frame, but with a few specific conditions attached.

The primary aim of this project was to build a Stealth Fighter with the very best balance of weight, power and range possible with essentially off the shelf parts. The Fighter frame is in my opinion the perfect base platform for this type of project. It has been designed from the ground up to be massively strong and rigid, but at the same time relatively light. If you put stock mountain bike wheels on this E-bike and deleted the battery, I suspect it would make a seriously capable downhill bike. Unlike converting a down hill bike to an E-bike, this frame is specifically designed to be electric. This means the batteries are fully enclosed in a unique Cro-moly monocoque frame, and the swing arm is engineered to handle a high-powered hub motor without fear of the motor ripping out of the dropouts under extreme load.

Goals for this build were as follows:

Main component selection was as follows:

Controller

First item on the shopping list was the controller. I had bee,n testing a modified 6-FET controller on one of my other E-bikes for some time now with some very good results. The results were good enough for me to be confident in using the same controller on this build. The unit uses an Infineon main board populated with 100V capable componentry.  This includes super-efficient 4110 FETS and 100V capacitors throughout. Battery and phase cabling are 12-gauge wire with silicone insulation and all the required plugs such as a direct Cycle Analyst connection, 3 speed switch, throttle, and programming point are fitted to the tiny board. Drop resistor values for low voltage supply to the controller are optimized for battery voltages of between 60V and 86V.

As with the modified Bomber, the controller was mounted directly to the  frame via the controller’s heat sink. The Fighter layout actually suited the internal controller installation quite well with a nice unused section of frame available just above the battery pack. A protective aluminium panel was then installed just below the controller together with an aluminium central divider plate for the battery packs.

Motor

Next on the shopping list was the geared hub motor with a Bafang BPM code-10 motor selected for the job. The code-10 winding is rated at 8.2-RPM per volt. A quick calculation confirmed that 40-MPH (64-kph) was achievable on a 70V / 18S nominal setup.  The motor was laced into a stout 24” downhill rim using good quality 14-gauge stainless steel spokes and nickel-plated brass nipples.

Mounting the new wheel assembly into the Fighter swing arm proved to not be as straightforward as hoped.  The Fighter has 150mm wide rear dropouts, with the Bafang being the standard 135mm.  This meant sending the wheel and swing arm back to the Stealth factory for reworking. Two weeks later, the modifications were complete including re-powder coating of the swing arm assembly.

Stealth factory modified swing arm

Batteries

Batteries were next on the list with 3 x Zippy 6S / 8-Ah LiPo battery packs ordered for the job once again from HobbyKing. This pack has a theoretical capacity of 600W/hrs, however the real world operation is closer to around 450-Whrs. For $300 landed, still not too bad.  The 3 packs were series connected to create an 18S/1P configuration. The pack was then installed in the E-bike’s lower battery compartment so as to optimize the front to back balance. As pictured below, the upper battery compartment is used for a second 18S pack to extend the range when required.

As with the Bomber, the battery and controller can be isolated from outside of the E-bike without removing a side cover. In this case, the battery to controller isolation is a little less elegant with the two leads simply exiting the frame just in front of the seat post.  The loop cable then tucks nicely within the seat post support framework, once it’s plugged together.

Bulk Charging.

Since the Fighter uses a much smaller battery then the Bomber, a much smaller bulk charger could be selected. In this case I used a 400W LiFePO4 from BMS-Battery, set up to cut out at 75V.  This charger is compact enough to store on the E-bike in a handlebar bag and still leave plenty of room for my wallet, keys, and phone. Again I want to stress that that although this is a really quick and convenient way to charge LiPo’s, you need to be fully aware of the risks involved and take the necessary precautions to protect both yourself and property.

Display

A large screen Cycle Analyst is used and mounted on the head stem instead of the smaller screen unit’s stock position that’s built into the frame. Personally I found the CA a little difficult to read on the stock Fighter mainly due to rake and angle of the frame. Having the large screen up on the head stem makes it very easy to read the display and see exactly what’s going on without taking too much attention away from what’s going on in front of you.

Human input

For human input, the E-bike uses the standard Schlumpf 2-speed bottom bracket planetary overdrive system. A 7-speed cluster was also fitted in readiness for possible future installation of a derailleur, however for now, just the 11-tooth gear is used. Having the two speeds is certainly adequate for commuting duties and the two available ratios work quite well with a comfortable cadence of 25-kph to 30-kph in direct drive, and a comfortable cadence of 45-kph to 50-kph in overdrive.

Braking

Braking duties are taken care of by a set of Magura MT-2 Hydro’s clamping down on 203mm discs back and front. These brakes are the best I have used to date, and they have an amazing feel and stopping power. One or 2 fingers are all that are need to pull the bike up. I highly recommend these brakes not only for their excellent performance, but also in terms of value for money.

Throttle and 3-Speed switch

As with all my E-bikes, I use a 3-speed switch to manage the behaviour of the bike. However, in this case I use the 3-speed switch in conjunction with a thumb throttle, as apposed to a half twist throttle usually found on Stealth Bikes. With the power level of this E-bike, I tend to set the speed limit with the 3-speed switch, then just mash the thumb throttle to the end stop.  I find this very comfortable and less fatiguing as you are not constantly adjusting the throttle to maintain a certain speed. Of course I can still modulate the speed quite easily when required.

Speed-1 accelerates smoothly and tops out at 20-MPH (32-kph).  This fits in really well with first speed of the Schlumpf and gives the E-bike excellent range in this mode. Speed-2 sees around 30-MPH (48-kph) and ties in well with the overdrive ratio of the Schlumpf. I tend to use this speed the most as it’s a good compromise between range and speed.  Speed-3 is of course unlimited and allows the E-bike to wind out to its maximum speed of around 38-MPH (60-kph).

Riding experience

The controller has been setup to provide around 2000W output. With a geared hub motor, 2000W feels very lively, especially off the mark. I think the bike would be quicker off the mark than a standard 3000W Fighter, however the stock Fighter would most likely reel it back in through the midrange. The E-bike feels incredibly light on the road and changes direction very quickly. I find I can brake really late into corners then, punch out of the corner at full throttle with full confidence.

Economy wise, the geared hub motor is certainly an improvement over the stock direct drive motor. I am seeing figures between 20% and 40% over the stock motor. However if pushed really hard, economy drops off to a similar level. This E-bike has been setup mainly for urban duties as opposed to the stock Fighter that has been designed more for off-road duties. The Bafang motor at 2000W is coping extremely well, with zero issues to date.  Although very little off-road work has been done with the bike, tests to date have found the bike to be very capable in the rough stuff also.

It was surprising though, how quickly the efficiency dropped off when pushed hard. Efficiency wise, I think the stock Fighter motor would overtake the Bafang motor under these conditions. I think it would also be fair to surmise that the stock Fighter motor would be more durable when used under these conditions. Fighter acceleration test:

Fighter Vs Bomber

So which E-bike do I prefer? The Monster Bomber or the Super Sharp Fighter? Although both have their merits, it’s the Fighter that wins out for me. I just love the fact that it still feels like a bike, and you can actually pedal it without power at reasonable speeds and reasonable distances. Although it doesn’t accelerate like a train, it still gives quite a reasonable kick, especially off the mark. Its speed is also more then adequate without going into an area reserved for motorbikes and motorbike safety equipment. The Bomber however, is far from retired and is now used mostly for dirt track duties. The bike is basically unstoppable and climbs like a Billy Goat. Also the big battery capacity gives you plenty of range even when pushing hard.

My biggest problem now is choosing which E-bike to ride…not a bad problem to have though!

Story Submitted by John “Kepler” Wessel of Melbourne Australia

Editor Note:  Kepler  is  a well respected guru in the electric bike community who on his spare time  invented his own friction drive system “the E-boost,”  a clean and efficient system. Also read Kepler’s review of the Stealth Fighter here.

Electric bike home builder Nader Alizadeh lives in Hamburg Germany, where electric bikes are popular, but restricted to a maximum watt limit of 250 watts. Unlike most home builders these days who focus on speed, range and affordability, Nader decided to focus on stealth and minimal weight, so that his E-bikes look and ride like bikes. Climbing hills is not an important consideration for him because where he lives is not very hilly.

To achieve his goals Nader uses small geared 250 watt hub motors which are light weight and small. He uses one of three manufacturers, either Tongxin,  Bafang or Cute but he prefers Tongxin because he finds them to be the quietest of the 3, and he has a local E-bike dealer who stocks them, so they are easily available (read our article on these 3 mini hubs). He uses 250 watt hub motors  in multiple configurations: front wheel drives, rear wheel drives, all wheel drives (motors in both wheels)  and recently even began crafting the ultimate hub motor application….mid drives. (read our article on mid drives).

How is it that one  home builder is able to make multiple electric bikes out of his garage that look better and perform better than 90% of the commercially available e-bikes in the USA for a cheaper cost?

Well for one he is making some pretty big compromises, settling for relatively small (180 watt hour) battery packs and small 250 watt hub  motors. (read our story that asks: Is 250 watts enough?) Since his components are so small they are easy to hide. Check out the $3500 Faraday electric bike for a commercial comparison.  Also he is starting with decent  and affordable platforms which are commercially available mountain bikes.

Although not speed machines, the benefits of Nader’s super clean looking and light weight electric bikes are obvious to a bicycle purist. Looking at his bikes, you can barely tell that they are electric powered.

Notice a few key features of Nader’s Bikes:

• All of his bikes are based on mid to high end  mountain bikes.
• Most all of his bikes run on 36 volts, and stay close to the legal limit of 250 watts.
• Most of his bikes utilize custom built 36V / 5-Ah 180-WH water bottle battery packs which is adequate for most of his rides
• When he needs extra watt hours he carries extra “battery bottles”
• None of his bikes weigh over 45 pounds even when using 2 motors.
• Most of the controllers are built into the rear seat bags.
• Most of the bikes are equipped with quality Schwalbe tires.

Nader is a collector at heart, and once he found the right combination of controller, motor and battery he repeated that winning combination, resulting in a garage full of very beautiful, yet similar E-bikes.

Lets do a photo tour of Nader’s stable of beautiful electric bikes:

This Bergamont bike has a Tongxin 250W hub motor in the rear. Notice how well the motor hides behind the rear disk and cassette.  Controller is in bag and battery is in water bottle.

This Marin bike has Cute hub motors in rear and front. Notice it has caliper brakes. Disc brakes are more popular /effective in high end E-bike conversions but are not always compatible with the hub motors. This bike has the controller built into the small frame bag, and the battery built into the water bottle.

This Fuji mountain bike is Nader’s first mid drive mountain bike utilizing a Tongxin motor built into the frame with a custom bracket to create a mid drive.

This Corracec Superbow has been converted with a Cute hub motor in the rear, a controller in the seat bag, and the battery in the  color coordinated water bottle.

This Koga Miyata has a front Tongxin motor, and a slick water bottle battery that matches the frame. As with most of these Nader bikes, the controller is hidden in the bag behind the seat.

This Heavy Tools electric bike is equipped with a 250 watt Tongxin hub motor in the rear, and a color coordinated black water bottle. Notice that most of Nader’s bike have quality Schwalbe tires.

This lucky Stork Rebel has been converted with dual 250W hub motors front and rear.

This mountain bike, being one of Nader’s first builds,  is missing the slick battery bottle of most of Naders designs, and mounts the battery in a frame bag instead that is not as well color coordinated as his other builds. It has a rear Tongxin 250W hub motor.

Nader would later convert the earlier bike, ripping off its unsightly stickers and mounting the 250W Tongxin hub motor into the frame to make a mid drive. Now the E-bike has one of those slick 5-Ah water bottles. This is one of our favorite mild-assist builds of all time.

Bellacoda Dowhill bike with 750W Puma motor in the rear wheel. This bike utilizes LiPo battery and fits 5-Ah in its small water bottle and 10-Ah in the tiny rear pack.

This classic Fischer bike has a 250W Tongxin front hub motor.

My favorite of Nader’s builds is when he puts the hub motor in the frame, and turns it into a mid drive.  What this does is allow the motor to run through the pedal bikes gearing system, making the ultimate in efficiency and hill climbing ability. To give you an idea of the capability, watch this video of Nader showing off one of his mid drives:

To see more video illustrating the effectiveness of mid drives check out our mid drive performance video story here.

Nik from Italy sent us pictures of his recently finished home-built mid drive mountain bike which is indeed another clean and elegant example of what can be accomplished from a garage build.

He calls it the “Spider Bike” and it  is powered by a 500W Cyclone motor.  Although 500 watts does not seem like much when compared to various hub motor powered E-bikes, this is a mid drive (as opposed to a common hub-motor), and mid drives are the ultimate in efficiency, especially when it comes to hill climbing (see our article on mid drives). With 500 watts you can easily use this bike as “an electric chair lift” to slowly but surely make your way to the top of a mountain, and then bomb your way down. This bike does not use derailleurs, but instead uses in IGH (internal geared hub) transmission, the German made Rohloff. (check out our article Rohloff on an electric bike)

The holy grail of mid drive bikes is full suspension mountain bikes which take full advantage of the mountain climbing capacity and perfect weight balance a mid drive offers. (Take a look at our mid-drive performance videos for more illustration)

The Spider E-bike has an electronic Chinese style dashboard mounted on the handlebars and is throttled automatically via the highest quality torque sensor available which is built into the bottom bracket (THUN  sensory BB-cartridges X-cell RT)

The bike has a 36 volt, 12-Ah, 432-WH, LiFePO4 Headway battery pack with a BMS.  As you can see Nik took the time to elegantly package his cells and BMS. This pack is better built than many commercial packs I have seen. Notice he took the time to include an integrated charge port.

Headway 12 cell model 38120S LiFePO4 10-Ah 10C

To achieve a decent full suspension mid drive is a hard task to accomplish.  Not only does the motor need to be mounted inside the frame’s triangle, but thats also the best place to put the bulky and heavy lithium battery. Full suspension mountain bikes do not have the large space in the triangle that a hardtail mountain bike would provide, so a quick and  easy solutions such a nylon triangle bag are out of the question. In the next picture you can see how Nik managed to mount both the battery and motor into the triangle. Notice that the bike uses freewheel crank arms, so that the bike freewheels like a regular bike when the motor is not engaged:

Part of the reason this E-bike came out so clean looking is Nik chose the very compact Cyclone kit as the motor and controller to base his E-bike. The Cyclone is an electric motor with a planetary gear box which ups the RPM’s the electric motor spins at, which makes it possible to link the motor with the slower-spinning drive train while still keeping the motor in an efficient RPM range.

By using a commercially available kit, Nik saves himself the hassle, complexity and unpredictability of trying to design a complicated mid drive on his own. If you want to build our own mid drive bike such as this, a good place to start is with a kit. Check out  our list of 10 commercially available mid drive kits.

To see other examples of elaborate home built electric bikes that use no kit (much more complicated builds) , check out  our articles on the Dogati and the Super Charged Big Hit.

In the next picture you can see  how the Spider E-bike’s components are laid out. The controller is up top above the battery. Because the controller is only running 36 volts at 15 amps it is fairly small and should be ultra reliable even when climbing.

To finish off the look the battery box is cut in a web pattern. Not only does this provide the spider look, but also is functional in that it allows air cooling for the components:

Word on the street is that Manny Da Silva (from Toronto, Canada) has put together an unusually radical idea for Tattoo and Piercing artists. When we first put out an article on Patient Zero it didn’t seem ready for the road. This chopper style bike features a beautiful hand built frame and a wonderfully handcrafted aluminum battery box.

check out the craftsmanship on this battery box

And some of the coolest “retro” battery gauges we have seen:

Although it looked pretty we had some questions. Why use SLA batteries, is the chain hooked up, and it weighs how much? Some of the techniques used on Patient Zero got us thinking, “Do they know about endless-sphere?” So, we at ElectricBike.com decided to follow up and contact Manny himself.

Patient Zero started as an idea to demonstrate green concepts with performance in an unconventional way. Manny is a former automotive technician, and he was asked if he could spearhead an electric chopper bike project. Manny tells us that Patient Zero was not his first electric bike build. He has experimented with various types of batteries, frame styles and hub motors for the past 5 years as a hobby. “There are other examples of my work out there”, he tells us.

Even with that experience, a team of skilled craftsmen were needed for some of the more challenging aspects of the build. Jason Parker is a well-known builder of custom motorcycles, and he took on the challenge of constructing the aircraft-grade aluminum battery box. The real leather seat was handmade by SaddleShoppe.com and other contributing members also sorted the anodizing and paint.

The E-bike uses a 1.2-kilowatt chain-driven motor connected to an 8-speed Sturmey Archer internal gear hub on a Surly “Large Marge” rim. When asked why not a hub motor, Manny replies, “ We find the use of chain driven motors more efficient than linear hub motors. It takes less energy to get the bike rolling.” With its current set-up, Patient Zero is reaching speeds of up to 50 km/h (31-MPH).

Beautiful mid drive system

Speed was not the main focus as a benchmark. “We know many guys out there with 2-kilowatt hub motors reaching serious speeds. Instead we focused on the distance”, Manny says. Patient Zero is the first electric bike we know of to use two separate battery chemistries to power one motor. It utilizes the characteristics of a 48V / 20-AH Ping battery for take off and hill climbing, while the 48V / 14-AH SLA packs are used for cruising speed when high amperage draw is not necessary.

“While everyone else looked at making things smaller and lighter we went the other way”, Manny states. All those batteries make up 100 of the choppers 160 lbs. “The weight of the bike provides much better stability when riding, especially in windy conditions”, Manny adds. All that battery volume amounts to a 100 kilometer range (62 miles) without pedaling once on normal terrain. So at full tilt you can get 2 hours of riding time on one charge. Not bad considering it takes 4 hours to charge the power system.

With so much weight moving at that speed, it requires some serious stopping power. Patient Zero is equipped with 8” disc hydraulic 4-piston Hope M4 calipers. To say it will “stop on a dime” just doesn’t cut it. These brakes are used in downhill mountain bike racing and have proven their reliable versatility.

Now for the final question we ask Manny, “Are the pedals working?”
“Yes and no”, Manny chuckles. We have a double sprocket that rests on the rear triangle of the bike. “The battery box was so wide we needed the clearance from the pedals to the motor”, he adds. It was noticed that the bulk of the sprocket set-up and chain covered the sponsors’ logos and so it remained off the bike until the new owner takes delivery.

Patient Zero’s last stop of this year’s tour is at the Montreal Art Tattoo Show September 7th, 2012.
If you want to know more about the build please visit Patient Zero Chopper on facebook.

https://www.facebook.com/PatientZeroChopper

I made a fixture that held both top tubes at once for the mitering process, shown here in the shop milling machine:

Because the motor exerts a lot of torque, the shafts have to be held very firmly, and aluminum just isn’t strong enough. Here, I’ve milled out the aluminum mount to hold a 304 stainless steel insert, to be held in with a couple 5mm countersunk allen screws. The slot is made using a boring head, and moving the mill table sideways. Depth of each cut is .025″

The axle holder is flipped over in the mill vise, and bored out to fit the BMX freewheel. Ultimately, it got redesigned and thrown in the scrap bin:

I had planned to hide everything Electric away under a large carbon fibre clamshell, but the motor shaft was wider than I expected, so the New Plan was to get the motor shaft outside of the crank arm circle. Which meant, upwards and forward. Instead of hiding everything Electric, I would now showcase the motor and everything else. I’ve always felt that each part should be able to stand on it’s own in terms of function and artistic design. I had an idea, but no actual drawing as I started making parts out of metal:

I used a 44mm head tube from Paragon Machine, and the tubing is 3/4″ 4130 with an .049″ wall thickness. The smaller cross braces are 5/8″ True Temper 4130 with an .035″ wall thickness. Tube bending from Andrew at Pacific Bending in Maple Ridge. Thank you. Tig welding was used to join all the tubes together:

These are the rusty plates of steel I am using for the rear dropouts. I have made a sketch and have a few measurements, and that is good enough. I thought the plates were mild steel, but as I started machining, I realized I had picked up some tough steel that had a very good carbon content. These will help to hold the Rohloff rear hub securely, giving eBee a 14 speed transmission:

There’s my cardboard template, and you can see the basic slot outline has been done in the milling machine, using a sharp end mill: 

I hadn’t been happy with the angular shapes of the 2 side plates, and one afternoon I had the idea to really enlarge the radiuses around the bolt holes, and then scoop out the material between those arcs. That looked much better. Here, the left side plate is mounted on the rotary table and a cut made to give chain clearance. I do not have a CNC mill. Figuring out 3 chain lines made me scratch my head quite a bit:

In total I made 5 sets of side plates before I “got it right”. Could I have figured this all out on a 3D drawing program like Solidworks? I don’t know. I think I need to have the metal in my hands, life size: 

I made a new rear dropout to replace the original Rohloff item. Because the rear frame is so low, the brake caliper mount can be canted forward much more. Material is 7075 aluminum: 

Setting up the chain stay jig to build the rear end. The Hope brakes and front hub have arrived. Nice stuff! 

The chain stays have been Tig-tacked, and now the seat stay jig and a big C-clamp hold it all in place:

The seat stays are now on, and it’s time to see eBee’s shape evolving and coming together. Yes, that is Bill and Hilary on my wall, in happier times:

 

Detail of the fillet brazed dropout holders, Hope rear brake, and Rohloff hub. According to Justin, the only 2 hubs that will stand up to continuous electric motor power are the Rohloff and Nuvinci hubs:

On the spot wiring diagram, courtesy of Justin:

This is the complete package for eBee, minus the motor: (left to right) the 25 amp controller, Cycle Analyst computer, Thun BB, and the lithium polymer batteries. The small but powerful batteries are normally for R/C hobby airplanes. They are connected in series to produce 52 volts, giving the Stokemonkey motor an output of just over 700 watts, which translates to about one HP. The Cycle Analyst display is from Grin Technologies, and is the latest 3rd generation model. You can program when the motor starts to assist the rider, and by how much. It tracks battery life, and will automatically partially shut down when the batteries get too low. It can tell you how much energy you put into the ride, and how much the motor put in…The Thun BB has integrated magnetic sensors that detect the mechanical strain on the BB spindle, and sends that signal plus the cadence signal to the Cycle Analyst, which tells the controller how much juice to send to the motor. A very slick system!

Other parts. This is a mount for hanging the batteries and controller from the (2) side plates:

Now in the mill vise, having the centre section lightened with a 1/4″ end mill:

Finished, except for anodizing:

I needed sprockets for the jackshaft, so I went to my local bearing supply house and purchased these two beauties, plus (2) bearings:

Sometime later, they were thinned, lightened, drilled, bead blasted, nickel plated, and ready for assembly:

I needed to make sprockets for the $35 crankset I got off Ebay, so I found an 1/8″plate of 7075 aluminum. Here it is setup on the rotary table, and 52 teeth means one cut with a 5/16″ end mill every 6.923 degrees. A little bit of concentration was required:

The boring head spins with a carbide insert tool and makes very smooth holes. The sprocket fits an 1/8″ X 1/2″ pitch chain:

eBee is starting to come alive!  There is still LOTS to do:

I needed to build a new stem cap to hold the Cycle Analyst computer and the fairing. I took two pieces of aluminum, held them together in the mill vise, and bored a 31.8mm hole. When I opened the vise, I had 2 pieces that looked like this:

In the front is the original cap, and above is the new one, about half done. Quite a lot of metal got removed:

 

Finished, and waiting for a coat of red paint:

I needed a head tube badge, so why not start with a solid chunk of aluminum?

The 6061 aluminum is bored to the same size as the head tube OD. The decal was photocopied and enlarged to 160%, then traced onto the tube:

Quite a bit was done in the mill vise with a 1/4″ end mill, followed by some hand filing and sanding. It would get anodized pewter: 

A lot of aluminum scraps got converted into eBee parts. A total of (46) machined parts were sent out for anodizing. This chunk of aluminum got used for the Cycle Analyst / fairing mount:

Here, the mount is slowly taking shape in the mill vise:

The finished part:

These are the holders for the (2) Rohloff cables, under the left seat stay. The radius on each end was done on the rotary table: 

Figuring out the shape for the fairing. The shape is developed using aluminum welding rods and a glue gun:

View from behind.

The welding wires were covered with masking tape, and fiberglas matt covered that, followed by bondo. This was sanded smooth to the desired shape, then primed, sanded, painted, polished, and finally waxed 5 times. This is the “plug”:

Here, gelcoat has been sprayed over the male plug. This is the start of the female “mold”. Over this many layers of fiberglas matt will be laid… this forms a very strong mold: 

This turned into a disaster when the plug refused to separate from the mold. It had to be chipped out, and the bondo softened up with successive coats of paint stripper. It was winter here, so a lot of the painting, stripping, bondoing, fiberglassing, etc. happened inside. I’m sure my shop was not the healthiest place to be. When the plug was finally out, I had a damaged mold, so that had to be repaired before I could lay up the little fairing: 

When eBee was mocked up, I took circles of masking tape, and placed them on the side plates to see where holes might look good. The side plate was then clamped on the mill table, and the centre of each circle was marked with a +. After the centre of each hole was located with the mill spindle, I used the digital readout to save time when going from hole to hole. The numbers in red felt pen are the X/Y co-ordinates: 

This is the final version of both side plates, ready to be sent out for anodizing. The colour will be pewter: 

Everybody has a Chris King headset, it seems. I like Chris King; I think he’s a great guy. However, I had some aluminum, and believe it or not, some spare time,  so I decided to make my own. It wiil be anodized black:

One of the last processes was to create the battery box covers, which are suspended under the electric motor. Working with fiberglas / carbon fibre involves making a plug, a mold, and finally, the part. The two parts have to mate, and have a certain depth, so I cut 2 pieces of aluminum to match. Then an aluminum standoff was machined and located:

Using bondo, some 2X3′s and plywood were glued on, and the rough form is starting to taking shape:

 

More bondo as the final shape emerges:

This is the desired shape, so now time for hi-fill primer, and the top coat:

Painted and waxed several times… shiny!  That’s me taking the photo. These are the plugs. Now it’s time to make the actual molds: 

The plugs get sprayed with gel coat, left overnight, then coated with many layers of fiberglas matt to create a strong mold: 

The molds have been separated from the plugs, trimmed, and mounted to plywood. Coats of wax to follow, then PVA mold release:

This is the carbon fibre cloth: it’s a very flexible weave, and quite delicate. From all the work in the shop, my hands aren’t exactly smooth, and little rough spots on my fingers would catch the cloth and separate the weave. I’ll bet the majority of people laying up carbon fibre in China are women… 

The cloth has been cut and placed in the bottom of the  mold, and now additional strips of carbon fibre will be added up the sides. I think the bends are too sharp to only use one piece of cloth:

This is not true carbon fibre work, as I am adding layers of fiberglas matt over top. I do not have pre-preg carbon, and an autoclave and vacuum pump in which to cure it. My parts will be heavier, but I will have that carbon “look”: 

These are the finished battery covers. They are not perfectly smooth. They could be sanded and clear coated numerous times, but there are only a few days left before the show, and my list still has many items left: 

Pinstriping by Paul. UFV sent me on a pinstriping course about a year ago, and I learned a few skills there. I don’t have the patience for the “classical” pinstriping where everything is symmetrical. I like quick, flowing, and random. Classical pinstripers would probably be horrified, but it works for me:

This little handlebar fairing to house the Cycle Analyst is fresh out of the mold, and needs to be trimmed and mounted:

It is now Tuesday evening before NAHBS. Justin (Grin Technologies) is helping with the final settings and wiring tweaks before eBee’s First Ride. We also got the speedometer hooked up, which is important, he told me. Our schedules are completely opposite. I have been getting up at 5:40am to teach Framebuilding 101, and Justin regularly stays up to 4am. It is almost midnight, and I have had some gin, so maybe that is why the photo is a bit fuzzy. The night is cold and clear, and Justin is first to ride eBee soon after this shot was taken: 

The Cycle Analyst is completely programmable, and also tells a story. Justin returned from his short ride, and eBee had gone 48.7 kmh, which is basically 30mph. Average speed was 30.2 km/h, including the turnaround at the end of the block. It is now my turn. I am exhausted, it is after midnight, I have my work boots on, and my blood sugar is low (I am a diabetic…) I ride anyway. eBee definitely needs some more setting up. The tires are too soft, forks need a lot of adjustments, and the Rolhoff that shifted well on the stand, doesn’t want to now. Probably the cables have stretched. It is pitch black except for the very bright LED headlight that is plugged directly into 52 volts. I cannot even see which of the 14 gears I am in. I pedalled about 3 crank revolutions and then the motor kicked in, and eBee accelerated! She definitely has a bit of go. How soon the motor kicks in, and how hard, is all programmable. During the evening, I managed to talk Justin into coming down to NAHBS, and he booked a flight. He’ll be there Saturday and Sunday. He’s definitely the man to talk to about this very slick electrical system:

It is now Wednesday AM, and another night with 5 hours of sleep has come and gone. I have to mount the battery boxes, do the final photo shoot of eBee, buy some clothes for NAHBS, and pack the bike and stand into a box. We leave tomorrow at 5:30am.

eBee was created in 90 days from start to finish. Unlike the 1888 Whippet, where I didn’t keep track of my actual hours, I can tell you that eBee consumed 485 hours of my life. I learned a lot, and have no regrets!  Thank you all for reading my story.

Paul Brodie

 

Occasionally we like to celebrate some of the heroes of the electric bike revolution. Aussie Jester is on our list of 10 most influential people of the ebike movement, and we have been intending to do an article celebrating his creations from the very beginning of electricbike.com. If you visit the “non hub” section of endless-sphere, it won’t be long before you stumble across references to a builder named Kim, from Perth in Australia.

His username is “AussieJester”, and as the name implies, he enjoys a good laugh. A quick search will reveal several build-threads for his E-bikes, which are simply stunning. Aussie Jester was involved in a tragic accident some years ago and lost use of his legs. That has not stopped him from building and riding some amazing electric bikes, and unlike most ebike enthusiasts he has an excuse not to pedal. His first electric bike was a trike:

From there Kim had the bug and went back to his workshop to create even a more fantastic ride…this time a bike and not a trike:

At the time of its creation, the Blue Cruiser is known to be one of the most beautiful electric bikes ever created. Aussie Jester is one of the biggest naysayers of hub motors that there is. He has coined the derogatory phrase “Frock Motors” (Non-hubs require a chain that can get caught on a frock [dress], so hubmotors are for frock-wearers!).  Kim’s motor of choice is the Turnigy 80-100, which he sets up with elaborate gear reductions so that it works a reasonable rpm. See the Turnigy 80-100 in our store.

Here it is before it became powder coated and the “Blue Cruiser” was born.

\

Here is the 100-page build thread of the blue cruiser on Endless-sphere:  And here it  is finished:

The blue cruiser was already a work of art that AJ was  quite fond of, so…when he got the itch for a new project, rather than drill, cut, and beat on it, the only logical solution was  to…make a completely new E-bike frame!

Kim acquired a compact 2-speed transmission from master fabricator “Thud” and decided it would go quite well with a particular motor he’s had his eye on.  http://endless-sphere.com/forums/viewtopic.php?f=28&t=48731&p=718406#p718623

AJ would name this bike the HOBO cruiser.  HOBO stands for High Output Brushless Outrunner, such as AJ’s favorite motor  the Turnigy 80-100, which weighs only 6 pounds and can put out 7,500 watts (10-horsepower!):

His controller of choice is the Castle HV-160 which can put out 160 amps at 48 volts (7680 watts) and it can fit in the palm of a hand while weighing less than a pound. No ebike controller on earth looks this sexy:

Like most high performance electric bike builders, AJ uses Hobby King LiPo as his battery source because of their high discharge rates, power density, and affordability. On the blue cruiser for example, AJ uses 8 X 6S 5-Ah LiPo packs @ 44v/20-Ah.

Here is a video of the working of the motor:

The HOBO Cruiser was born, which is a 2-speed 45-MPH monster:

Here is the video of the Hobo Cruiser:

In this video you can see some of the things that Aussie Jester loves about his RC motor drive set up:

The awesome noise (AJ has said this is his favorite feature of the RC drive system)

The power.

The top speed.

The efficiency.

The opportunity to show the skill it took to build one.

Aussie Jester is a builder who has overcome great adversity, to build from scratch custom electric bikes, instead of just slapping a hub motor on a mountain bike (like most ebike builders).

For more examples of super fast home builds read our 10 fastest electric bikes story.

For more examples of RC drive reduction systems, read our Astro Terrifying Speed Story.

With all these sexy,  sleek, and expensive production bikes hitting the market in the last 6 months (Specialized Turbo, Stromer ST1, Neo Jumper, Currie Eflow) it is tempting for the home builder to just go out and buy one. They are breaking the 20-MPH legal speed limit (between 20-25-MPH) and doing it with torque sensing systems that make them a really sweet hybrid that is super lightweight (for an ebike) and still pedals and feels like a bicycle. Not surprising, some ebike builders are inspired by these bikes, and have decided to build one of their own. (See our mini mountain bike story for some great examples).

Home builds offer the advantage that you are able to build a bike at a more affordable price, while using higher quality components, and are able to break the watt and speed limits that exist in most countries. (read our Ebike legal story)

Home builds are usually a lot sloppier and heavier than a production bike, but there are a few builders who are capable of building an ultra clean home build…Kepler is one of those.

Kepler’s Background

John “Kepler” Wessel of Melbourne Australia is known in the DIY community as the builder and modifier of  fast electric bikes. He is known as an owner of a Stealth Bomber that he modified to have a top speed of  close to 60-MPH.  (read our story on Kepler’s modifed Stealth Machines) He also owns a Stealth Fighter which he modified to be more lightweight    Read his Stealth Fighter Review.  Kepler is  a rare breed of  Endless Sphere member who really appreciates not only the power of electric bikes, but also the elegance of keeping them more like bikes…most notably being light-weight and clean looking.

It was this fixation on lightweight bikes that inspired Kepler to develop his own drive system, which is a friction drive using a tiny RC motor. The Kepler drive system was ideal for quickly converting lightweight road bikes and other production pedal bikes into simple and lightweight electric bikes with moderate power and speed levels.

Kepler and Production Bikes

Kepler is a hard man to impress when it comes to electric bikes. He was impressed however when he got a brief test ride on a Neo Jumper (read our review), and it was that experience that spurred the thinking necessary to sell his beloved hot rodded Stealth Bomber (read about that amazing ebike), and look for something more tame and civilized. At first he thought he would buy the $4,000 Neo Jumper, but the price tag and the fact that it was only 250 watts, made him look for other alternatives. In the end, Kepler decided he could use his skills and build a better ebike (this time a tame and very stealthy E-bike) and even save some money.

Kepler made a splash in the DIY community when he suddenly announced he was putting his  Bomber on the auction block and was thinking of buying a lightweight under powered Neo Jumper. Trade a 60-MPH Stealth Bomber for a 20-MPH production bike? Endless-sphere die hards were banging their heads against their monitors and throwing up their keyboards and mice.

Kepler decides to build a 29er Carbon electric bike

Kepler writes:

“Recent experiences with the some nice quality commercial e-bikes got me fired up to look at building a low-powered but high-speed commuter / flatbar road bike that would be hard pressed to even be recognized as an e-bike by the general public using the local bike paths.

As a bit of back ground, after having a quick test of an e-motion Jumper just around a parking lot, it felt so impressive that I seriously considered purchasing one. So the next move was to go visit the suppliers and take the bike for a proper test ride. First impressions were very good with some nice assist. However, the bike was limited to 25-kph assisted as per Australian / Euro regulations. So to ride the bike at a decent speed, you needed to work twice as hard because effectively the motor-assist was doing nothing for you, and you were now trying to push a 40-pound bike at a decent speed.

In addition to e-biking, I have to admit I am a closet Lycra  and average about 100-km a week on my carbon road bike. Every time I get on this bike I am always blown away by the efficiency of these modern high performance road bikes. I have no doubt I could average a better speed on my road bike then I could on an Australian regulation compliant e-bike.

So with this in mind, I figured it was time to blend the best of both worlds and build an e-bike that free rides as well as a high spec road bike but at the same time had e-assist capable of a sustained 50-kph under favorable road conditions.

The process of gathering components was then started. The cornerstone of this build is a full carbon 29er frame complete with rigid carbon forks. I decided to go down the path of a 29er because of my height and the fact that it is a mountain bike frame and as such provides a bit of extra strength. Total weight of frame and forks comes to 1.8kg. Nice start. “

RC friction  Drive

Kepler is the inventor of the Kepler friction drive.  (read our article on friction drives) It was a natural choice that he would go with his own drive system on this new bike.  For this bike, many custom pieces were designed in Solid Works and fabricated to hold the drive and  controller:

Hiding Components…a home builder challenge

Hiding the battery pack and controller are tricky for the home builder.

Kepler hid his RC controller under the seat:

Like many home builders these days, Kepler went with low cost, high energy density LiPo Hobby King cells. He decided to hide them in a pack behind the seat. This looks super stealthy and neat, but he is only able to hide  44V / 5-Ah for a total of 220 watt hours…not a very large pack, but…it’s easier to hide and it makes the ebike lighter and more like a bicycle:

The nemesis of the ebike builder is where to hide all that wiring.  Most ebike builders don’t really worry and let all the wires hang everywhere strapped down with zip ties and duct tape. This is not Kepler’s style, and he was looking for an exemplary fit and finish in his ultra stealth commuter. This is one huge advantage that production bikes have over most home builds. The hollow purpose built frames  provide many easy hiding places for wiring, and since they are usually made in China, they have cheap labor to spend hours hiding it all:

A full carbon-fiber frame presented a new set of challenges for Kepler when it came to the  hiding wiring especially the bulky battery cables.  Most would consider the obvious solution was to just run the wiring inside the frame.  However carbon frames are highly stressed and can not be drilled without risking their structural integrity.  Subsequently another solution needed to be found.

The solution came in the form of custom carbon fiber cable covers made from thin walled carbon fiber tube.  These covers were carefully cut to match the profile of the frame so as to  look like part of the original bike.

RC plan aborted!

After completing the bike as a RC friction drive, Kepler made an astonishing “about face”. Even though the bike ran as fast and smooth as expected, there was one element Kepler could not stand. RC drives are notoriously noisy (I know exactly what he is talking about). I abandoned my mid-drive  Optibike based on the noise factor alone). On an ebike, for which the intention was to ride completely unnoticed on bike lanes etc, and did an effective job of appearing Stealthy, but it did not seem right to Kepler that the bike gave itself away with a loud “weed whacker”  noise coming from the motor. Kepler decided to strip the bike of the RC motor and drive system, and go with a traditional hub motor in the wheel instead.

New Plan, Stealth Hub Motor Build

Kepler decided to go with a compact geared motor but resisted  going too small just for the sake of weight savings. A compromise between weight and power was struck with a Bafang SWXH high torque (but low speed) motor selected for the job. At 6.6 lb, this was not the lightest hub motor on the market. However to withstand what Kepler planned to throw at this little motor, some thermal mass was a must have requirement.

This motor is rated at a meager 250 Watts when using 36V, however…Kepler knew from his experience with similar geared hub motors that the motor was capable of much more.  How does 75 Volts and 950 Watts sound?  Enough to maintain 35-MPH under safe conditions, and climb most hills at speeds that even Tour de France competitors would be proud of.

However, we were now talking about using over one horse power through a set of dropouts not designed for the high twisting loads associated with electric hub motors. To get around this issue, a custom made torque arm was made that transferred the motor’s twisting loads from the chain stay dropouts to the far more robust disc brake mount.  Power could now be confidently applied without fear of the back wheel being ripped out of the bike.

New Controller and Mounting Position

Hub motor controllers are not known for their compact size especially when designed for high voltage and high power.  To get around this Kepler took a standard low-spec / low-powered compact controller and rebuilt it using 100-volt capable componentry. It was then configured to take advantage of all the latest features available through the latest Cycle Analyst. To continue with the stealth theme,  the controller was mounted beneath the bottom bracket with much attention paid to keeping the controller as water proof as possible.

Connectors were fully water-proofed using a custom machined front junction box that was machined out of a block of High Density Poly-Ethylene (HDPE) which machines very easily.

DIY Torque Sensor

Kepler originally decided to set the bike up with a simple RPM sensing pedal assist.  However, this method of pedal-assist soon proved too rudimentary for this build and was subsequently replaced with a far more desirable torque-sensing bottom bracket. Again, the V3 Cycle Analyst  was used to take full advantage of this method of pedal-assist.

Dashboard

Here you can see the “control panel” of Kepler’s Super Commuter. He is using a Cycle Analyst v3 which is the most sophisticated electronic dash available for electric bikes, and will tell you within a few hundred yards of when your battery is going to die. The Cycle Analyst measures exactly to a tenth of an amp how many amp-hours (Ah) have been used from the battery. It will also calculate your watt hours used per mile and many other useful stats.

Also, I notice that Kepler chose for his hand grips the same comfortable grips used on the Stromer ST1.

Although the bike is a pure pedal assist with no traditional throttle fitted, there is still plenty of power delivery control available at the handlebars. To the left, a button can be seen next to the shifter. This can be pressed any time to override the pedal-assist and provide boost for taking off from a stand still, or making a quick overtaking move on an unsuspecting Lycra.

On the right there is a 3-position switch (Red) that sets the level of assist. Actual pedaling effort is measured through the Cycle Analyst via the torque sensing bottom bracket. The level of assist is then scaled against the amount of human effort applied. Switch Position-1 requires strong pedaling effort to get the level of assist up. Positions-2 and -3 make it much easier on the rider with the added bonus of position -3 having fully variable assist via a rotary knob, within easy reach between the 3-position switch and gear shifter.

Other neat features include the ability to see the actual human Watts produced by the rider plus cadence, so you know exactly how much effort you are putting in. An accurate summary of the rider’s wattage input over the length of the ride is also displayed together with power consumed, so you can see exactly now much you contributed to the ride.

Worth noting also that the Cycle Analyst can run up to 3 different fully programmable profiles. In Kepler’s case he has programmed an “off road” 950W  profile, an Aust/Euro compliant 250W / 25-kph pedal-assist profile, and a USA 750W / 20-MPH compliant profile. Although the bike tends to stay in the “off road” profile most of the time, a fully compliant profile is only a few button pushes away (in our Getting Away with Riding an illegal bike story we mention a turbo button such as this).

Tires

All ebike builders know that tires can make a huge difference on the way an electric bike rides, as well as its efficiency and top speed. Kepler originally fitted 700 x 28c Gator Skins to the bike, to keep rolling resistance to a minimum.  However, he soon found that the combination of a rigid carbon-fiber frame and skinny 100-psi sports tires was simply too unforgiving on a commuter that spent much of it’s time on bike paths. To help improve the overall ride, a set of 700 x 38c Hybrid tires were fitted. This made the bike far more compliant and comfortable to ride with only a minor sacrifice in overall rolling resistance. An added bonus was that puncture resistance was much improved making the bike ideal for road, bike path, and packed trail riding conditions (flat tires on an ebike are more of an issue than on a pedal bike, read why).

Brakes

Kepler wanted this bike to be the “whole package” with as little compromise as possible. This braking setup was no exception. A set of Magura MT2 hydraulic disc brakes were selected for the job complete with floating discs back and front (same brakes as used on Specialized Turbo). These brakes are designed for heavy downhill duties, and as such provide incredible stopping power when used on such a light bike.

However, Kepler admits to perhaps getting a little too carried away with the brake spec and found the 203mm front rotor just too much for the bike, with even one-finger application being capable of throwing him over the handle bars.  To rectify this, the 203mm front rotor was replaced with a more conservative 180mm rotor.  This calmed the stopping power down nicely, and at the same time improved overall brake modulation proving that…bigger is not always better.

Bike fitted with the massive 203mm front rotor.

Bike now fitted with the more appropriate 180mm floating discs back and front.

 Home Built vs Production Ebike

The Specialized Turbo has a 250 watt motor, the Neo Jumper has a 250W (or 350 watt motor depending on what country you buy it in). The Stromer ST1 and the Currie Eflows have  500 watt motors. Keplers tiny motor burns up to 950 Watts, making his bike considerably faster than any of the previous bikes. Also Kepler was able to use higher-end components than those bikes including a carbon fiber frame and high quality hydraulic disc brakes. Total weight of the Super Commuter (25 pounds / 11.4 kg) is considerably lighter than all of those production ebikes.

 Lightweight Build Accomplished!

Kepler’s Super Commuter came in at 25 pounds…not the lightest electric bike ever (see our story on the lightest) but definitely lighter than any production electric bike on the market now.

A  lot lighter than Kepler’s Stealth Fighter (60 pounds! 27.2 kg), which he modified to be lighter than stock (read story about modifying the beast). It should be noted that the Kepler’s Stealth fighter is a totally different class of ebike.  It has a real full suspension…It weighs 60 pounds but has a 40-MPH top speed and a range of 35 miles. Notice he needs to pick up that bike with 2 hands where as the Super Commuter he can pick up with one:

For an  ebike to have ultimate performance (speed and range) you inevitably have to add weight to the bike. Kepler tries to make his electric bikes as light as possible while achieving the performance he wants. Obviously, riding the Super Commuter is a totally different kind of riding experience than riding his Stealth Fighter. Having both bikes in his garage he can choose based on the type of ride he is in the mood for.

Riding Impressions

According to Kepler:  On 12S LiPo (44V nominal) and 350W, the bike will reach around 21-MPH (35-kph) on flat ground when unassisted. A bit of pedaling and still maintaining 21-MPH will see the motor-current drop off to around 200W on flat ground. 15-MPH was easy to maintain on gradients that normally see me drop down 10-MPH unassisted.

On 18S (72V nominal), speeds of up to 35-MPH could be maintained on flat ground with around 650W required for this sort of speed. With some pedaling effort  this drops down to around 500W. Not great for maximizing range but nice to have when you want it. Its worth noting that both 12S and 18S setups will provide all the power this bike needs.  However Kepler has now settled on 18S as the default battery configuration to take advantage of the higher cruise speeds associated with the higher voltage.

Estimating the range of an ebike can be a difficult task with most manufacturers quoting unrealistic figures based on an ideal set of conditions. On Kepler’s bike, having the ability to measure human input as well as electrical input makes for a far more realistic range estimate. Kepler reports that he likes to contribute an average of around 150W, and can track this average input in real time when riding.

On the low assist setting, the Cycle Analyst is programmed to set a power-to-assist ratio of 2:1. So in other words 150W human input will see the motor assist providing 300W. With 300-WH of battery on board (as pictured above), we now know that the bike will be able to run for an hour at this pace. With 450W total pushing the bike along, Kepler can confirm the bike will hold 25-MPH on flat ground.  So based on this data, the realistic range of this bike is around 25 miles at this pace.

 What did it cost to build?

Kepler spent $3,000 total on this bike. Of course he needed to spend many hours of skilled labor putting it all together, which are not factored in this cost.  The project took 2 months in total to complete, with around 5 hours a week spent working on the bike. The benefit of home building is you can get a much better deal than if you spend the money on a retail bike, and get something that is “illegally” fast.

Compare the Super Commuter to the cost of a production bike which is not as fast, not as light, and certainly not carbon-fiber:

Specialized Turbo 45-lbs $6,000

Stromer ST1 Platinum: 63-lbs $4,000

Easy Motion Neo Jumper 50-lbs $4,000

Currie Eflow 52-lbs $4,000

For more information you can read the entire build thread for the Super Commuter on Endless Sphere.

Gavin (from Dallas, Texas) is a full sized E-biker (His endless-sphere username is “Drunkskunk“), and he felt somewhat cramped on most of the available frames. Plus he wanted a fat bike, which are not yet available in full suspension.  So…since he owns a welder…he did what any other garage builder would do in that situation. He built his own full-sized fat bike off-road frame, that he designed to be a hub-motored E-bike, with a large battery pack built into the downtube assembly.

The motor he chose is the Crystalyte motor (read our review), which he plans to run 5-10,000 watts through in gradual increments (as he works the bugs out).

Gavin decided that rectangular tubing would be much easier to weld. The swingarm shock below is a Marzocchi Roco, which is 9-inches long with 3 inches of travel.

Paint day…there’s nothing stealth about this Ebike!

“…Here’s what I’m stuffing it with. Twelve 6S/5-Ah packs, grouped into three strings of 4, with the mains and the balance taps wired in parallel, then stuffed into my bike’s extra tight hole. And I do mean tight. It took 10 minutes to squeeze these things into that hole. It’s 18S, peaking at 75.6 volts right now…”

The large 1332-WH pack Gavin wanted almost required him to make his own frame.

The tires are Surly Larry 3.8-inch fatties riding on 65mm extra-wide rims, using 12-Ga spokes laced by JRH at Holmes Hobbies. This beautiful custom red frame was left exposed, and the battery compartment panels were covered with a pebble-finish truck-bed coating. Since the bike is proportional to Gavin, it may not look that large…until you read that it has a 57-inch wheelbase! The front brake disc is 9-inches in diameter.

“…It seems my tire circumference is 91 inches, exactly. And…I’m doing 39.7-MPH top speed at 75 volts…”

The front has a full 12-inches of travel provided by a set of Marzocchi Super Monster forks. The black shape just in front of the bottom-bracket is a Lyen 12-FET controller, which is known to handle 45A well. Gavin specified cool-running and efficient authentic 4110-FETs to get the most out of this popular controller.

The centralized location of the large battery is a great place to locate the pack, and it minimizes the impact of the added weight. Rear-mounted batteries are easy to mount to an existing frame, but they make an E-bike tail-heavy, which affects the handling.

A full-sized bike needs a full-sized hub, and Gavin chose a Crystalyte 5404 (X5-series 40mm wide stator, 4-turns per tooth). Says Gavin: “…Riding the bike is Simply Amazing. It floats over speed bumps, curbs, stairs, small Hondas, the screaming fleeing masses. Its a Monster!”

For this bike to NOT be subject to scooter laws, it has to have pedals. The single-speed chain uses a 36T/22T gearing.

This is one of the first full suspension fat bikes, and the first full suspension electric fat bike we have heard of. Electric fat bikes have been popular lately in the DIY community (read our story on electric fat bikes).

Non-hub builds have the weight of the motor more centralized, so they are more nimble. Also, giving the motor some gears increases efficiency while reducing motor/controller heat. However…some builders simply love the near silence of a powerful hub. Silently gliding through an off-road path on a powerful full-suspension E-bike is an experience that I highly recommend.

Here’s the build thread for this impressive E-bike:

http://endless-sphere.com/forums/viewtopic.php?f=6&t=38667&start=100#p716192

Every once in a while we see an ebike that breaks the mold.  Imagine instead of investing in a small pick up truck, you bought  an ebike large enough and powerful enough to carry a descent amount of cargo, and do so on pennies a charge.

Bill Stites is a former chiropractor turned talented designer and metal worker that is working on a new creation in one of the most creative ebike meccas in the world:  Portland Oregon. Portland is a combination of eco minded people, one of the best bike infrastructures in the country, and a hilly terrain that begs to go electric.  In fact Portland has been called “the ebike capitol of the country“. Portland is especially known for its electric cargo bikes.    Bill found a new nitch in taking the cargo bike to a new level with an electric cargo  bike large enough to make deliveries of large and heavy products. Bill thinks of it as one of the most efficient electric bikes imaginable.  The Truck Trike can carry up to 600 pounds and is designed with commercial enterprises in mind that want to reduce their eco foot print and at the same time save massive money on gas and parking cost.

Read how an ebike can save you money.

Rugged Frame Lovingly Built

Each frame is hand built by hand in Bill’s Portland Shop.   It is built  of  steel to be extra strong and rigid. This is the 3rd version of the frame, and each one has gotten a bit better, stiffer and stronger. If you wonder why this ebike is so expensive, you could start with an intricate steel frame that is made in America by expert craftsman.

Propulsion system

The Truck Trike uses one of the highest quality (and expensive) hub motors available which is the v2 BMC (read our review).  You can choose for your Truck Trike to have a one or two wheel powered drive. With 2 BMC hub motors, one in each rear wheel, there is a $2000 up-charge. Then you get double the torque and double the power, and double the battery.

The Truck Trike can come with one 48v 20ah battery, or 2  batteries if you go with the 2 motor system giving you a total of 40amp hours.

For the single motor system, the price is $7,850 and for the dual motor system you are looking at $9850

Unfortunately the Truck Trike comes stock with heavy lead acid batteries, but for a price you can upgrade to a lithium ion All Cell pack which I would recommend for battery longevity and weight savings. On a trike that is so heavy to begin with, forget lugging this thing up stairs etc, so running lead acid isn’t as much of a deal killer as it would be on a standard electric bike.

I would expect with 2 BMC motors you could expect a top speed of over 20mph on level ground, and can could climb just about any hill. I would expect a 20-40 mile range with the dual battery/motor system, depending on what you are hauling and how hilly the terrain.

Creative Human Input

Motorcycle Brakes

The  Truck Trike isn’t  like anything that has come before in the bike world.  While it is a “hybrid” relative to its power sources [human + electric], it also can be described as a hybrid in its overall configuration.

The front end is easily recognizable as a bike.  But the rear end – with its 600+ lb. capacity – is more like a truck.  While Bill  tried to stay on the level of bicycle components for ease of availability and maintenance, it became clear that there were no bicycle brakes – even downhill hydraulics – that were up to the task of stopping upwards of 1/2 ton of mass [vehicle+driver+payload].

Thus, motorcycle-level hydraulic brakes  were specced for the rear section.  Such technology is well-proven, and readily available. Even though they are heavier than regular brakes, on the huge Truck Trike a few extra pounds equates to almost nothing.   The motorcycle brakes  provides full confidence in the ability to stop a fully loaded Truck Trike even when trucking down steep downgrades.

The photo below shows identical wheels with a bicycle rotor on the left, and the new motorcycle rotor on the right.  Bill  designed and machined a custom adapter to mount the monster rotor on a bike hub’s standard 6-bolt pattern.

 Who Would Buy One?

The Trike Truck costs $9850 in its awd configuration.

The Truck Trike would be awesome to own for anyone except for three  huge factors #1 the cost. #2 the space it takes to park it.  #3 275 pounds makes it one of the heaviest ebikes on the planet.

The Truck Trike was designed with the business owner in mind who can actually save money by owning this  trike.  Also, it is possible that someone could base a new start up business around this Trike, for example a bicycle messenger who can deliver refrigerators, or an electric-powered  pedal cab driver, or an electric lawn care business that carts their electric lawn mowers on a Truck Trike, or a high tech newspaper deliveryman who has a helper in the back throwing out the papers while he Trike Trucks down the road. The Trike Truck is Safe, heavy duty, and clean looking, and would attract a lot of  positive attention to any business.

Fact Sheet

•Truck Trike is 48″ wide x 113″ long

•Rear Flat Bed = 48″ wide x 58″ long

•275 lbs. Gross Vehicle Weight

•600 lbs. Payload capacity

•Highly Efficient: note that Payload Capacity is greater than Vehicle

•Formidable Vehicle: 275 + 600 + 150 [driver] = 1,025 lbs. = 1/2 ton

•Saves money by eliminating fossil fuel, and requires low maintenance.

•Simple design eliminates key parts – no transmission, no differential, no

cross-axle. Wheels are independently powered – human to the front, electric

•Intended for Business and Institutional Use, including warehouse and

•Designed for increasingly dense urban environments.

•Active Transportation = Health benefits, and healthcare savings.

•Human Power input is signficant at this scale.

•Street Legal, and still qualifies as an electric bicycle under Federal and

Oregon laws, thus no license, nor registration, nor insurance is required.

•$7,850. for Standard Version [single motor].

•$9,850. for Heavy Duty Version [dual motors].

•Designed and Built in Portland, Oregon.

•Intended to contribute to Climate Change solutions and Peak Oil adaptations in particular, and the Green Economy in general.

For more information visit the Truck Trike Website.

This story was written by Kingfish, electricbike.com contributing writer who is known for building bikes and doing epic 1000 mile +  rides on them.  Kingfish is a talented engineer and problem solver. This story is focused on the building of his magnificent ebikes, and not the rides themselves which is another story. 

I’ve always been a purveyor of All-Wheel Drive (AWD) systems and it probably comes from time spent off-roading with my cousins as a squirt. Both my uncles have 4x4s, and buggies, and ATVs, and on and on… When I grew up, ordered up my 4×4 truck exactingly from the factory. It pulls the moon! There’s just one problem: Mileage… which is in the ditch.

But damn I love the feeling of control and power at all wheels when conditions are dodgy!

When I set out to build my second electric bike in the winter of 2009, I ordered a full-suspension frame and two full ebike conversion kits (F & R rim brake) from ebikes.ca. Excited too when the packages arrived shortly after Christmas! But the Engineer in me couldn’t be repressed and I took apart a controller and the rear hub to see how it worked: They’ve remained that way since, although serving a purpose as a frequent model for measurement and contemplation.

Began with the 2009 Felt Compulsion-1 Frame purchased off of eBay for about $800 USD.

With only a front hub system left, my AWD ebike would have to wait, instead converting my 19-yro Specialized Rockhopper MtB into a Front-Wheel Drive (FWD): Rode it hard and aggressive right into the ground, lasting barely a year. Much was learned from this wild tangent, namely working through the um… “unique characteristics” of Chinese engineering, and applying mods along the way. Joining Endless-Sphere (ES) was immensely helpful with collective minds solving everyday problems, and especially rising to interesting challenges. For my part, I was on a mission to ride (pedal) from Redmond Washington to California and back – fulfilling a childhood quest.

For where I live in and around hills and forest and city, there was no hesitation: I desired a 2WD ebike because we have dodgy winter conditions that make it very difficult to get beyond this little Redmond hamlet up over the steep hills to work. Plainly my 4×4 could do it and I wanted that out of my ebike too!

As such, the first year (2010) was spent sorting out basic noob issues: Batteries, charging, charging in the field, packaging batteries into ever-increasing assemblies, controller mods for more power, try every tire, every seat, every light, every gadget, every garb, and even every helmet. By Christmas, the MtB shocks were blown out – and without parts I finally made the move to the Felt Compulsion frame.

“P0″ started out as a 1991 Specialized Rockhopper conversion. The variant above was used for the February 2010 Chilly Hilly event with two battery packs and a range > 75 miles.

Being completely new and late model there were lots of great choices for building up what has become my favorite bike to date. It started out as a leggy FWD pony with the over-sized frame adopting every electrical component from the previous ebike. Although I took the path of rugged aggressive urban assault very seriously and embraced new disc brake versions of the same 9C 2806 hub motors, ordered about February though arrived late May of 2011. That delay put a crimp on the summer schedule.

Sidebar story: In the first year – 2010, I ran out of time for my California challenge trying to assemble the full-suspension ebike. With no time left I used the FWD Rockhopper instead, threw it onto Amtrak in Seattle – riding it down to Klamath Falls and saving 4 days. Over the next two weeks, I traversed 458 miles over 3.5 days in the saddle down to Sacramento and then caught the midnight train back to Seattle. The trip was a partial success, although the hardtail frame beat me to death… and I swore never to wear a backpack again.

Back to 2WD build: The 2011 trip to California would require extra planning and capacity so I built this custom trailer using a “jumper” style BMX bike frame with a pusher RWD motor; together I’d have this “push-me pull-you” system. You think 6 months would be enough time for planning and assembly, but the last 6 weeks was intense, working from sunrise to 1 AM trying to finish it up. Finally, all appears ready, committed to leaving, jump on the bike, hit the throttle – and nearly died from the torque and oscillation that was running through the frames. Failure: Back to Square One.

The delay to re-engineer fixes cost about 3 weeks, though solved the basic problem by moving the RWD onto the bike – thus creating the original 2WD dream! Other issues were corrected as well: When you have a bike & trailer loaded up with 100 lbs. of LiPo and tools and supplies and clothes and food… well it gets pretty heavy and that load has to be placed precisely otherwise the slightest wind or divot in the road can cause a spill. Fortunately I live in and around one of the steepest plateaus of the region and was able to model progressively larger loads, learning how to drive it at the same time, discovering the tipping points, and the limits of both man and machine. Make no mistake – that bike was loaded to the gills, and then I headed on down the road to California leaving Redmond about Noon – in the rain.

P0 Opportunity-charging beside a vending machine: July 1st, 2010 – my first road trip to California and ran out of power.

I didn’t get very far before thinking this was a crazy mad idea and by the time I reached Renton 30 miles away I was certain I was crazy! At least the rain quit. But from then on, like emerging from under a cloud, the sky brightened as did my disposition, and the Great Experiment proceeded to unfold mile after mile beneath two electrically driven wheels. Not without a hitch; there were constant problems and some critical fixes along the way. Several kindred Friends of ES gave safe harbor to my passage and provided illumination, as well as timely adjustments to my ride. Without that, I certainly would have failed.

The power afforded by 2WD is incomparable to single-wheel of similar measure because there are two wheels turning against the ground, digging in traction, and moving the bike forward. As Samwise Gamgee said to Frodo Baggins in LotR: “Share the load!” And that’s what 2WD does: It splits the load between two motors, it divides the heat of strain – and the motors run cooler because of it. Now we can apply more power, climb hills faster without fear of sag or roasting wires, and we don’t have to pedal as hard. When the road becomes really dodgy, we’ll have two wheels pulling us through the muck. Don’t get me wrong, single wheel drives have their place: They get better economy, they are simpler to install and maintain, and the cost is about ½ as much.

The 2010 road trip had all the single-wheel benefits described above as well as the issues, especially the heating problem. That bike, counting myself weighed about 350 lbs. plus 33 lbs. of LiPo. For 2011, the load was closer to 450 lbs. with 100 lbs. of LiPo. By the end of that trip I had traveled 2515 miles over 28 days, exceeding the official world record by 600 miles. It was tense and stressful at the beginning, though by the end I had mastered control over this heavy assembly using feather-light touch… literally finger-tips to maintain balance. It was an engineering gamble as much as a personal journey and an adventure, with thrills, chills, happy smiles and frights all rolled up. Every day you meet someone new from all walks of life who want to know more about your odd-looking ebike. The rich unique experiences cannot be distilled easily, just as it is difficult to summarize the genuine contribution and help each ES member invested to see me onward. The coin of friendship and camaraderie in this field of study is the best symbol of wealth I have ever collected.

P0 on the road, July 3rd, 2010 about midway through the Sierras pausing to review relics of the past.

I have only told part of the story about this ebike.

There was in fact a profound opinion held in my circles of discovery that the pursuit of 2WD “is flawed”, that Rear-Wheel Drive reigned supreme in all forms now and forever. Learning how to coax both motors to cooperate thus was a tangled affair with experience gained in fits and spurts. The biggest challenge was unifying the controllers and instruments. Initially I had a Master-Slave arrangement where instruments went to the primary controller and the slaved controller got what was left. The connections in-between were crude, exposed to the elements, and perhaps under-driven. To make matters worse, the cross-over cable between the controllers was placed directly behind the seat-tube and directly in front of the rear fender with a good deal of dirty overspray.

Assuming knowledge of the preceding year – it is by sheer luck that I was able to complete the 2011 road trip! Two pesky motor issues dogged me the whole way: The first was “contention”; where one motor works against the other. The Naysayers said it could not be resolved using my techniques, however it was managed by making the two wheels different sizes (26” on the front, 24” on the rear), by programming slightly different power outputs with the front down-rated by 10%, and by fortune of environment where rarely was the land level and without wind. Using Cruise Control effectively self-managed load to the wheels: One motor hanging back and contributing as needed.

P1 as FWD with an early version of the front fairing. I was at a Teriyaki restaurant when a man entered and said “Who owns that ebike?”. I waved so he comes over and says “I understand the model name is “Hot Wheels”, but who’s the manufacturer?”

The second and much more annoying problem was loss of power during hill climbs on twisty roads. The rear hub tended to drop out when load reached a certain level… not on a straightaway, but when turning up a winding road – like Hwy 1 along the west coast. The solution was not simple and would have to wait until summer of 2012. Indeed, I cataloged a list of fixes, but the worst developed two months after returning to rainy Redmond when both of these new motors rusted out solid by mid-November 2011.

Imagine Oliver Hardy saying: “Well this is another fine mess!” How is a person living in the Pacific Northwest supposed to get on down the road if their motors rust right out? Instead replacements, I set out to correct the obvious production flaws. The heart of the issue is that Chinese manufacturers cut costs and didn’t bother to varnish iron stators like you’d normally expect with an automotive starter or alternator. Not the case here: When the motor becomes hot, pressure builds and vents; when the motor cools, water vapor from rainy conditions wicks back in creating Amazon-like conditions which precipitate rapid rusting and ultimate failure. The problem was solved during spring/summer of 2012:

Began by with discussing the issue with my local body shop and they suggested using a product called Rust-Mort which has a high-concentration of Phosphoric acid. Applied in thin coats, the thick acidic gel penetrates rust, converts it into Iron Phosphate crust which is easily removed, and finally seals the surface in preparation for immediate varnish of which several light coats of automotive-grade were applied. Scale on the inside of the Aluminum covers was blasted clean and a set of weep-holes was added along the perimeter so any new moisture would have an exit route. Finally the cheap low-end bearings were replaced with top-flight high-speed stainless steel, with new seals, and upgraded the phase wires to 12-AWG. In brief –the condition of the motors was revised from “dodgy low-end” to “high-speed high-torque and all-weather”.

Beneath the skin: P1 in July 2011 displayed without fairings during conversion from FWD to 2WD.

Moving into summer 2012, I replaced the troublesome Master-Slave controller arrangement into one of equal paring; both controllers were replaced with late models and modified identically, ripping out the redundant GND wires of instrumentation and unifying into one connector (leaving Cycle-Analyst and Programming leads unaffected). In addition, converted the Hall Effect wires to USB, the APP Battery connectors to high-current EC5, and the APP Phase wire connectors to HXT 4mm.

The 2012 upgrades solved two issues: First, removal of the problematic Anderson Power Poles (APP) – the source of charring and melting and highly resistant connections, and second, redesign of the entire battery harness from 10-AWG to Marine-Grade 6-AWG wire with stringers of 8-AWG to each battery assembly. This work greatly increased integrity of power throughout by simplifying connecters and the count of connections, exchanged soldered joints for copper-swaged, and lastly – by lowering the resistance of the harness for higher throughput. In brief, the pesky source of sags was eliminated for the win.

The last item which gives this bike unique distinction is the fairing: It starts out as a funny story about my very first and second-to-last public bike event, which being the only electric bike – I won, although in truth it was not a race. Anyway, they assigned a “number plate” which I stuck on the front and I liked it so much that I kept it for bragging rights… but then I noticed a slight improvement in mileage. In those days the battery pack wasn’t large so it was easy to spot a couple extra miles when you only get 20 off a charge. On a lark, I created a body-fairing from HDPE for the MtB when I took it to California that summer in 2010. I really liked “the look of it” and decided in the fall season to add a front cowling, sort of a rain and wind deflector if you will. Again mileage improved 5 or 10%. About that time I crafted a custom battery bag for the triangle space which could hold a large array of batteries and extending range to about 50 Seattle miles. During the rainier season of winter the pack was getting wet, so I fabricated a water-resistant shell using a combination of marine vinyl and HDPE. This gave the ebike a very distinctive sleek look and was easier to keep clean.

P1 as 2WD with trailer (“P2″) on July 26th, 2011 – the first day of my 2nd road trip to California.

The full-suspension frame had a larger triangle. During the transition from FWD to 2WD I changed the pack from 10S (52V) to 15S (63V), and moved the controllers to reside behind the seat on the rear bike rack. The front fairing was then redesigned to be more aerodynamic. For the round-trip to California during the summer of 2011, I created an aerodynamic-looking trailer that was more egg-shaped with larger-end at the back for drag; the bottom of the trailer was completely flush, covered by a sheet of HDPE. The stability was most profound bombing down west on Hwy 88 from Carson Pass into Jackson California at 44 mph! After that second Cali trip I became more interested in speed: The 2012 rework greatly improved the top end from 38 mph to 47, and the latest fairing changes included more side-panels and flaring around the rear wheels. Right now it can coast faster downhill without pedaling than a roadie in a crouch! Let’s not forget this ebike experiences parasitic drag from two hub motors, so without question the fairings are a real boost to performance.

In all this talk about the bike, I forgot to mention charging: I started out with a 150W charger which is fine for a kit battery but not for cross-country. In summer 2010, I crafted a 350W Meanwell assembly but the 10S18P battery took nearly 12 hours to recharge. I didn’t want to go through that again, so for summer 2011 with the pack at 15S26P built a new 1kW Meanwell assembly and got those numbers down to about 8-9 hours. I’ve charged both at home, in motel rooms, and opportunistically. On the Road, I prefer to charge during downtime – like sleeping, and do so without fear. I also run without a net: No BMS. Instead I prefer to manually balance as required through occasional monitoring. I know what I built, and like an old friend I’m comfortable with it.

Finally I’d like to close by saying “Work always continues”; the refinements never stop. They say that “necessity is the mother of invention”. Well… I drive nothing else, and I am constantly thinking of things to fix or invent. The 4×4 remains on blocks collecting dust; in a couple more years I’ll be able to register it as a “classic”. In the meantime, the 2WD ebike has proven to be more fun and healthy, and not only that – but I get a kick out of it!

Stats:

P0 – FWD

P0 back in December 2010, just before the front shocks blew out. Schwalbe Marathon Winters held up well.

Frame: 1991 Specialized Rockhopper hardtail w/ original Rockshox, code named “P0”. Retired December 31, 2010.
Key features: Fairing, brake lights, good speed and range, “yellowjacket” theme.
Weight (before/after): 31 lbs/60 lbs. For the 2010 Road Trip: About 190 lbs. sans rider.
Largest Battery: 10S18P LiPo, 52V @ 90Ah/4680 Whr.
Fastest Speed: 47 mph downhill on cross-country. Preferred: 28-32 mph.
Range: Farthest was about 175 miles – mainly downhill from 5,500 feet to sea-level using a 10S18P pack + opportunity.
Motor: 9C 2806 FWD rim brake, programmed to 1.5 hp. Highly modified 36V 6FET controller.
Estimated Cost: > $2800 with a commuter pack of 10S8P.

P1 – 2WD

P1 with sporty fairings and saddlebags in April 2013 just before swapping out the winter tires. Range was about 60 miles at 35 mph; with warmer weather gear – up to 100 is possible.

Frame: 2009 Felt Compulsion-1 F/S bike, codenamed “P1”. Born on January 1, 2011.
Key features: 2WD, full-suspension, better fairing, full indicators, trailer, hill-climbing, speed and range, B&W “orca” theme.
Weight: about 110 lbs. 2011 Road Trip w/ trailer: Between 240 to 290 lbs. sans rider.
Commuter Battery: 15S6P LiPo, 63V @ 30 Ah/1890 Whr. Optional Saddlebags add 67%.
Largest Battery: 15S26P LiPo, 63V @ 130Ah/8190 Whr. About 100 lbs. with trailer.
Fastest Speed: 47 mph on a flat; > 50 mph downhill. Preferred: 30-35 mph.
Commuter Range: > 50 Seattle-hilly miles, about 100 w/ Saddlebags.
Farthest Range: With trailer, 167 miles on a single charge, and 187 miles with opportunity.
Motor: Modified 9C 2806 F&R Disc brake, programmed to 2 hp each. Highly modified 100V 12FET controllers.
Estimated Cost: > $5000. Add $3500 for cross-country pack and trailer (+ 150 lb. capacity).

Timeline

• 2009 September: Search for ebikes and kits begins. Ordered in December.
• 2010 January: Converted Specialized Rockhopper MtB as FWD 37V 10 Ah LiFePO4; range is about 22 hilly miles with the wind at my back. Max speed was about 24 mph.
• 2010 May: Upgraded to 10S10P LiPo, completed my first electric Century in preparation for cross-country, and repeated the feat again in June.
• 2010 July: First cross-country trek, from Klamath Falls to Sacramento, 458 miles total
• 2010 Fall: Built custom battery bag, front and battery bag fairing. Mounted studded tires in November. Commuting 35 miles daily.
• 2010 Dec 31st, retired FWD Specialized Ebike. January 1st, 2011 – Felt Compulsion Ebike born as FWD.
• 2011 Spring: Parts ordered for summer road trip, including custom trailer. Assembly begins in May.
• 2011 July: Felt Compulsion Ebike converted to 2WD; July-August on the road to California and back – 2515 miles in 28 days.
• 2011 Fall: Commuting 50 miles daily to Seattle. By November both hub motors rusted out solid.
• 2012 Spring: Fixed hub motors. Inched back into riding again with lots of mods planned.
• 2012 Summer: Replaced entire Battery harness and connectors. Replaced controllers and entire instrument harness.
• 2012 October. Replaced front fairing, added new side fairings. Set new personal speed record at 47 mph on a flat. Phatty studded tires mounted in November.
• 2013 Present: Upgraded saddle bags to EC5 connectors to allow for century rides. Replaced kluge fenders. Planning next mods and trips.

Click here for complete information about these bikes – and more.
Safe travels, KF

Written by Ron/Spinningmagnets August 2013

Endless-sphere.com member “MattyCiii”  decided to put together an extensive build based on a Norco A-line full-suspension off-road bike. With most builders, I have to pry important details from them so our readers will be able to know that “if I do this, I will get that”, but Matty?…he readily supplies all of the details to anyone who is interested.

“…I’m using Magura Gustav M brakes on the rear because of the tiny, ~10mm clearance between the left-hand chainring and the brake rotor. The rear suspension shock will be a used Fox DHX 5.0

BB kit is an Schlumpf/ATS drive. The wheel gears are a  NuVinci N360 with a 20T sprocket, electric power on the left via a Recumpense DaVinci drive. Chain tension is an upgraded Surly Singleator.

I’m aiming for 12S LiPo (32-Ah), for ~50V hot of the charger. That’s all the Castle HV160 can take. The motor is an AstroFlight 3220, 4 turns of wire, terminated in WYE. I have to reduce that speed back down to something useful, with the large diameter of those monster tires. The motor mount is water-jetted aluminum that is 0.375″ (9.5mm) thick from bigbluesaw.com.

I started with high C-rate (30C if I recall correctly), 8-Ah batteries, that were bundled as four parallel, ensuring the load on any one cell is not too high even under high demand. Eventually I’ll be using MethTek Low Voltage Cutoff (LVC) boards to ensure I don’t bottom out any one 4-parallel cell bank. The batteries came with 5.5mm bullet connectors on 8awg wire, and I changed them to 6mm bullet connectors.

Now, I normally ride with just a 12S/2P 8AH for 800-WH of power @ 50V. This easily gets me through the 16 mile commute with 1/3 of the pack to spare. Plus I have room in the enclosure for the other half pack to re-install if I ever want to go on a looooong ride.

I charge through the balance taps now with a BC-168.

Primary drive belt is 20T/100T 5:1, and the chain secondary is a 13T freewheel to a 52T chainring 4:1, for a total of 20:1. It’s good for a 33-MPH top speed.

I checked out the data log on the Castle HV-160. I never peaked more than 70 amps. Watt hours per mile was in the high 30′s, acceleration is great…and the motor is only slightly above ambient temps when I touch it at at stops.

Acceleration with an RC drive is always insane. I consistently dial the throttle mapping to within 10% of its minimum on the CA-V3. So on Prelim 6, I run the bike at 0.09 volts per second on a scale from 0.01 to 99.99.

I now have an ebikes.ca analogger. Initial tests show the motor never gets above 50*c in aggressive urban riding with lots of stop & go and hills. I plan soon to start gearing down (say 15:52 on final reduction) for more top speed, knowing my motor will get hotter, but…will likely still be within its heat tolerance.

My first wheel-set: Spokes by JRH, rims from the Recumpense 47mm wide, 406mm diameter rim group-buy.  The tires were Pirelli 16″ x 2.5″ ML75 moped tires. Something I never would have thought would fit a 406mm diameter rim without the ES collective knowledge base. It turned out they dropped the bike too low.

So then…I upgraded to the 21″ x 1.6″ motorcycle rims,  I found a road/slick tread, 21″ x 3″ tire. http://endless-sphere.com/forums/viewtopic.php?f=6&t=37207&start=100#p618044 JRH carries 13-Ga spokes that have oversize nipples using #10 stainless steel washers,  I stacked two washers on each spoke nipple. I only have about 4mm clearance between the Lefty and the tire up front!…”

“…I took a short test ride…the beast is heavy…It’s about 120 lbs with battery. I’ve ridden it quite literally up and down a flight of stairs, which is easy for the bike but challenges the gonad fortitude of the driver.”

“…The N360 plus a Schlumpf High Speed Drive gets me 360% gear range at the rear, and 250% at the front. There’s some overlap so it’s not quite as tall a range of these ranges combined – but I’ll tell you I have a granny gear so low it’s hard to stay upright at 80-RPM cadence, and yet can pedal power to the right side freewheel at 33-MPH, so it’s a good gear range…”

“Up front the fork is obviously a Cannondale Lefty (of course) that was custom machined by Project321 (http://www.project321.com/), who was incredibly helpful in getting me the right parts to fit a lefty fork to the Norco”

xxx

Even though the bicycle spokes were fairly large, they needed washers to allow the motorcycle rim to be mated.

I really am fascinated by water-jetting, laser-cutting, and 3D-printing. You draw something on a screen, and hundreds of miles away, a machine does all the difficult cutting. Here, Matt drew this custom motor-mount and rear axle drop-out holder combination, which also extended the wheelbase a little.

The “750 Watt” wording is a joke. 750W is the national power limit in the USA, but Matts bike is occasionally seeing peaks of ~48V X 70A = 3400W

Matt was fully aware that adding weight near the rear axle adds “unsprung mass” to the suspension. However, he contemplated a wide variety of options, and this was the least objectionable for his goals.

He decided he wanted a “front basket mount” for the weight of the battery pack to have an acceptable weight distribution and balance.

The custom-ordered drop-out extenders/holders were machined by a CNC mill (Computer Numerically Controlled).

It looks like Matt made sure every part of his build was designed for strength instead of shaving grams for the lightest weight…I like it!

Here’s Matt with his creation at a July 2013 “Boston Bike Party“

Edit: Matt just sent me an update:

I’ve gone ahead and reduced the gear reduction from the previous 20T:100T / 13T:52T (1:20 reduction ratio overall) to 20T:100T / 15T:52T (1:17.3 reduction ratio overall). The motor runs a little hotter (50*C very consistently at the motor) as does the controller (temp peaks of 70*C at the controller) .

I’m seeing up to 120 Amp peaks now via both the CA-V3 and the Castle Creations data-logging. And my new top speed is 37-MPH. My goal is to get this bike up to a 40-MPH top speed, then install a 3-speed toggle switch where position: (1) is a kill switch, (2) is speed governed to 25-MPH tops (street legal in Massachusetts, and (3) is unlimited “for off road use only”

build log: http://endless-sphere.com/forums/viewtopic.php?f=6&t=37207

Written by Ron/Spinningmagnets, September 2013

I don’t know what’s in the water that they’re drinking down in Australia (or is it the Aussie beer?), but whatever it is, there seems to be a high incidence of “custom E-bike fever” there. Roger (ES member “Rodgah”) lives in Caloundra, on the North-Eastern “Sunshine Coast” of Queensland, Australia. This awesome frame was custom TIG-welded by his friend Paul, (ES member Timma2500)

Our website tracking shows that our readers respond well to stories about the high-end and high-power builds, so…how about an E-bike using 100V?

Build log:

http://endless-sphere.com/forums/viewtopic.php?f=6&t=36682

Specs:
2005 Specialized Big Hit FSR, custom cut and modified
2011 Rockshox Domain RC forks, with direct mount stem
Hayes Stroker Trail hydraulic brakes
FSA Gravity Cranks
24″ Fire-eye Rims
3.0″ Halo Contra tyres
Carbon fiber quick release battery cover

Crystalyte HT3525 rear hubmotor
12 gauge spokes
12-FET controller, with a 3-speed switch (limited to 50A/5,000W = 6.6 Horse Power)
CA-DP, CycleAnalyst-Direct Plugin
Magura throttle
24S-2P / 10-Ah LiPo (86V-100V, 3.6V-4.15V per cell)

Charged by a Hyperion EOS1420i 550W

Four custom 6mm-thick torque arms

Whole bike weighs in at 35kg (77-lb)

Many of the bicycle components were purchased from http://www.chainreactioncycles.com/us/en

With the paint removed and the frame thoroughly cleaned, the battery box can be drawn and the best placement can be determined.

xxx

I have also used a angle-grinder with an abrasive disc as a cutting tool. Beware of kickbacks (I have a scar on my chin), and it is an absolute MUST HAVE to wear eye protection. I use swim goggles now, after some sparks and grit bounced around my face and some got in behind my eye-glasses.

xxx

Timma said he can control the heat and metal-warping better with TIG, although other methods will work when welding aluminum alloy.

xxx

After installing a very large battery, he still had room to spare!

xxx

Specialized’s Big Hit is known to have a well-sorted suspension

xxx

A carbon-fiber access panel finished off the professional look of this awesome build.

xxx

Roger didn’t want the extra-heavy weight of a 530X series rear hub, or a Cromotor. By going to a 100V system, he could get awesome performance from a lighter 35mm wide stator, like the Crystalyte HT3525 he chose here.

xxx

Dry-fitting parts to find any potential fitment issues.

xxx

5000W / 6.6-HP twisting at the axles would kill the stock drop-outs instantly, so custom torque-arms were drawn and the shape emailed to a laser-cutter.

xxx

Due to the thickness limits of the laser-cutter, Rodgah ordered four 6mm thick torque-arms.

xxx

heat-treated aluminum has a tendency to snap when it breaks, instead of bending. By using 24mm’s worth of steel thickness (12mm on each side), this ensures the torque-arms take all of the twisting-axle forces, and none are transferred to the aluminum drop-outs in the frame.

Below is a pic of a 24S / 1P string made from four 6S bricks of LiPo, pic from ES member Sacko. Rogers pack is similar to this, but not identical.

Four of the popular 6S bricks connected in series to get 24S. Rodgah needed two of these strings to achieve 24S / 2P for a nominal 88.8V that is actually 100V when fully charged. 10-Ah isn’t a large pack, but Rodgah had to cut back on the battery volume to fit the higher volts he wanted. If Rodgah re-configured this exact pack as the popular 12S /44V voltage, this same 880-WH size of pack would be a whopping 20-aH!

xxx

If you have the option of using higher voltages, you can achieve significant power with fewer amps. It is the lower amps and the resulting lower heat that allows Roger to use 5,000W on a rear hub as light as this without frying anything.

There are many different component weight distributions that are acceptable, but whenever it is possible, this is the absolute best place for the weight of a significant battery pack. The large red kill-switch is vital, and needs to be located where it is within easy reach, whenever you are using 100V.

The small chainring maintains a high ground clearance when crawling over trail obstacles, but it also limits the rider to only adding some pedaling when the bike is at a slow speed.

xxx

If you watch the video, you’ll hear how quiet a powerful rear hub can be (the squeaking noise is the front disc brake). This quiet performance of Roger’s E-bike allows him to roll along the gorgeous coastline of Australia’s world-famous beaches without drawing too much attention. It’s quite stealthy…until he comes to a stop. He is then quickly surrounded by interested bystanders with non-stop questions about this outstanding custom build.

4-minute ride video (second video out of three): http://endless-sphere.com/forums/viewtopic.php?f=6&t=36682&start=25#p759229

Here are some performance quotes from the build-log:

“…The only riding that makes the motor hot is stop/start full-throttle action. If I keep my momentum up, the motor and controller stay dead cool. I could imagine going full throttle up very steep and long hills would heat it as well, but I have yet to find a hill big enough for the motor to even get warm, plus I have a bit of sympathy if I am climbing slowly…”

“…I don’t have a CA [CycleAnalyst E-bike computer] yet, I just feel the motor every now and then [with my hand] and it hasn’t even been what I would call hot, just warm…and that is rare, most of the time it is cold. The HS3540 is a lot faster winding than mine so I would assume it would get warmer riding like that. The 12-FET is modified by Hyena, I don’t know how. I leave mine on the middle setting of the 3-speed since that settings top-speed suits me and the power is fine, I guess it is probably less than 5-kW”

“…I went for a ride yesterday with my friend “thecopterdr” http://endless-sphere.com/forums/viewtopic.php?f=28&t=45409. Great to ride with someone else and have a chat. Managed to get my hub nice and toasty definitely above 50-degC [95C / 200F is a common heat limit], climbing slow and rough technical trails, though I am sure without motor power most people wouldn’t be able to pedal the whole way up. The other bike has a Cyclone mid-drive that was only warm at the top so it was a really good comparison of eggs vs eggs (although the Cyclone was noisy). I have a suspicion that most of the heat may have been caused by the low average speed (pretty tight and technical trail) and not so much the climbing itself, I’ll have to test this more in the future…”

“…I can imagine the motor doesn’t transfer heat very well to the outside, I have only once made it hot enough that I could just hold my hand on it, IR thermometer said 50-degC, but that was from constant stop and start slow monos for more than 5 minutes, the rest of the time it is cool, ie: less than 30-degC after a long ride. I think the trick is to keep the speed up, and have some common sense when climbing or going slow….works for me anyway!…”

Jay’s controller mods (ES builder Hyena):

“My usual mods are beefed up traces and phase wires and then the software flashed to suit. And of course running 4110-FETs. If dealing with noobs I will say “custom firmware tune” as this is easier to say than explain about phase currents, LVC etc. In the past I’ve also added bigger caps laid sideways along the board and fitted thermostats to the FETs to prevent overheating (N/C thermostat in line with the ignition wire) but for general use this isn’t really necessary. And it’s cheaper now to just step up to an 18-FET, than non-Chinese labour for doing these time-consuming mods.

Email is the best bet for contact, hyena.industries@gmail.com
or my website hyenaelectricbikes.com , though it’s rather out of date these days and badly in need of an update and freshen up“

Written by Ron/Spinningmagnets, October 2013

The featured custom build this month is from Miles, one of endless-sphere.com’s most helpful and respected members, who lives in S.E. London, in the UK. Rather than the high-powered builds that we normally showcase, Miles’ E-bike is a high-quality and very efficient city E-bike that is light, compact, and runs extra-quietly. The design process for this project started around 2006.

The drive configuration is a dual parallel right-side drive, with both the pedals and the motor independently driving the rear wheel. In order for the two drives to remain completely independent of each other, the motors’ rear pulley includes an integral freewheel, as does the pedals’ front chainring. A major influence on Miles’ decision to pursue this style of configuration was a custom E-bike that was built by Randy Draper of Maui (in Hawaii, USA). Randy was a pioneer in the practical development of this type of drive system.

The rear wheel incorporates a SRAM “Dual Drive” hub, which uses three internal gears, in conjunction with an external derailleur-activated sprocket set on a freehub. This provides the motor with three speeds to choose from, and the pedals have 12 speeds at their disposal.

The motor is a very quiet direct-drive unit, which powers a single-stage belt drive to the rear wheel, which also runs very quietly. The entire drive system is ”barely audible in most surroundings”

From this angle you can see the aircraft-inspired space-frame design.

The Moulton name might not be familiar to most North American bicyclists, but it is a respected name in the UK bicycling community, and they are known for their frame engineering.

The history of this unusual frame is interesting. Alex Moulton had a background in aircraft design working for BAC, and he made several bold and unconventional choices when he started this bicycle design in 1962. His family business was connected to the rubber industry, hence the desire to incorporate rubber suspension units, if that proved to be appropriate. He is most famous for his work developing the light and compact suspension of the original “BMC Mini” car.

Alex Moulton died at the age of 92 in December of 2012.

Here is the graphic from a 1966 patent showing the Moulton bicycles’ 50cc gasoline engine-assist version. Both the motor and the pedals make use of the Sturmey-Archer 3-speed internally-geared-hub. Miles credits this as one of the biggest inspirations when he decided to create an electric TSR27

The distinctive feature of Moultons is the smaller wheels. The trend for adult bicycles since the “Safety” bicycles of the 1880′s had been towards larger diameter wheels coupled with fat tires, in order to deal with coarse road conditions. Smaller diameter wheels are stronger and lighter, and the smaller cross-sectioned tires have less rolling resistance.

The decision to eliminate fat tires directly influenced his next innovation. This model has full-suspension, which was quite rare on a bicycle in the 1960′s. The length of suspension stroke is not long, but it is adequate for civilized road conditions. One of the main design considerations for this type of full-suspension is that; the design of each part of it was chosen for it’s lightness. The front girder-style fork has its spring very cleverly hidden inside the frames head-tube.

Concerning lightness, this has been the overall theme of these bicycles. This is apparent in the most eye-catching feature of the bike, the space-frame design of the bicycles main frame. It is very strong and rigid, and yet it remains surprisingly light. Moulton was also a leader in promoting a uni-gender frame shape that has a low top-bar for easy mounting.

From this angle you can see the front girder fork linkage.

This build is based on a Moulton TSR27

-Custom-built Planet Rider brushless permanent-magnet motor.

-SRAM Dual Drive, 3-speed Internally-Geared-Hub (with 4 derailleur sprockets retained).

-Freewheeling crankset.

-Gates Powergrip 8M GT3 belt transmission (16T to 100T, 6.25:1 reduction). Rear pulley is 263mm diameter.

-Sprague clutch in hub of rear pulley

-NiCad power tool batteries, 36V 4-Ah, in backpack (this was the battery he was using in 2008).

-Weight (without battery) 16.5 kg (36 pounds)

-Averaging 12-WH per mile

“…With the present 36 volt set-up, I’m getting a top speed of about 19-MPH so, with a more optimal 48V set-up, about 26-MPH – which is all I need…The belt drive is pretty quiet, as is the motor – noise is something I care about. You could approach someone from behind in a park and they wouldn’t hear it…I’m convinced that belt drives are the way to go…It’s designed for hill climbing, top speed is 22-MPH at 39V. It pulled up a long 20% gradient with ease…Over mixed terrain, for speeds under 18-MPH (with no pedaling at all), I was getting 15.7-WH per mile…”

“…I’d prefer it if I could fit sturdier tyres on mine, but using the Stelvios was the only way to create enough space for the motor…” (Schwalbe Stelvio 406mm / 20-inch)

Here’s the inside of the “Planet Rider” motor (no longer made). Note the integrated centrifugal fan for air-cooling.

Motor 

“the nice thing about this motor is the form factor – the case is only 60mm deep…this motor is one of a small batch made by a company called Planet Rider, almost 5 years ago, but that was it…It never went into production, I’m afraid…”

The maximum speed rating for the motor is 4,000-RPM, weight is 5.5-lbs

Kv = 59-RPMs/V

Ke = 17 V/kRPM

Kt = 0.17 Nm/A

Resistance: 0.25 Ohms

Inductance: (approx.) 200 uH

12 Poles / 12 magnets

Air-gap radius: 40mm.

Motor-case diameter: 142mm

Motor-case width: (excl. shaft) 60mm

Shaft diameter: 5/8″ (15.9mm)

Controller

Nominal input voltage: 18V-48V (max. 55V)

Continuous output current: 20A

Peak output current: 35A

Output power (max.): 1,000W

Measured no-load current of motor: 0.8 A @ 38V

Here’s a close-up of the two parallel drives. The Badge on the seat-tube shows that this Moulton was manufactured by Pashley Cycles, who started making bicycles in 1926, and who has been manufacturing Moultons under license since 1991.

Miles’ choice of rim brakes instead of discs was in keeping with the original design theme of lightness for every component. This bike can easily be carried indoors, or up a stairway.

The rear “spring” for the suspension is an elastomer ball, but its simple shape belies the sophistication hidden in the design. It works quite well, and remains the lightest possible solution that provided adequate performance.

The custom electric drive:

“…The 100T rear pulley itself is from the crankset of the Strida 5.0 (you can buy the whole crankset as a spare part), I had to re-machine it a bit, though. The 16T 8M motor-pulley was a custom job, the smallest commercially available is 22T and the smallest recommended size is 18T, but it works fine…16T to 100T is only 6.25:1, though….It’s just a standard one-way clutch bearing (from Tsubaki [Japan] and is equivalent to a CSK35P), used as a freewheel substitute. I only made the housing/adapter for it…

…To get a greater reduction ratio, in a single leap, you have to move to 5M size belt, but this means a completely custom large pulley…5M pulleys are available down to 12T but 16T is probably the smallest of any use in a one-step drive…Probably a good compromise between torque transfer, reduction ratio and size would be to use 18T to 180T 5M (10:1)….”

“…..The cranks are freewheeling, using a White Industries ENO 22T freewheel on trials cranks. I had a chainring made especially for it, but others have made adapters to standard chainrings. The 22t ENO has handy circumferentially milled weight-saving slots that one can use for fixing…not that it’s a problem to drill the fixing holes, with a suitable drill…

…So, the one-way bearing isolates the motor drive so that you can pedal as a normal bike, without any extra drag, and the freewheeling cranks decouple the pedals when you use the motor without pedaling. For normal freewheeling, the original freewheel in the hub gear kicks in, of course…”

Miles carries his battery pack in this backpack, in order to keep the bike itself as light as possible for lifting up stairs.

Battery

“…I’m using 36V 5-Ah high power density NiMH cells…I have to carry my bike up and down steps whenever I use it. Having the batteries in a backpack makes the bike itself an easy lift…”

Miles’ prototype motor design

Miles has been pleased by the performance of this drive system, but since the original motor is not in production, he has spent quite a bit of his spare time these last few years by studying motor design. He did this in order to establish what kind of a design could provide the same performance, but in a smaller package, and with the highest possible efficiency.

This project is nearing completion and here is the discussion thread for his 90mm (3.54-inch) diameter motor.

A computer simulation has indicated this 90mm diameter brushless inrunner could have up to a 95% efficiency.

The eMoulton build-log: http://www.endless-sphere.com/forums/viewtopic.php?f=6&t=5313

Written by Ron/Spiningmagnets, November 2013

Alan is an electrical engineer and drives a Volvo station wagon (endless-sphere username: Teklektik), so it’s no surprise that when he wanted an electric bike for errands and a bit of exercise, he built a 2WD cargo bike. He has produced one of the most professional custom builds I have ever seen. In Alan’s build-thread, he wanted to share his expertise in the electrical field, so he provides schematics and every possible detail about what’s needed to create a comprehensive E-bike electrical system.

I wish I had a way to get to work like this New England bike path. The trees changing color in the fall would be beautiful.

General Notes

The choice of 2WD was made for redundancy to achieve a “limp home” mode and avoid getting stranded far from home with tons of groceries on board. Alan relates that he has smoked a controller 9-miles from home, and  simply switched off the offending controller, reset the breaker, and continued on his way!

Alan lives in a mixed rural/suburban (and fairly hilly) region of Connecticut where 15% grades are difficult to  avoid, and 10% grades are common (nothing is level). When running on a single motor, the bike will do 32-MPH  (CA-limited to 1650W), and with both motors it will do 40-MPH drawing 3300W. The dual gear motors make the bike torquey over a broad speed range, responding briskly to the throttle off the line, and providing a combined 150lbs of thrust.

Two thumb toggle switches on the left grip allow selection of one/two motors and lo/med/hi power levels to allow a variety of modes for different riding situations. Hills are usually tackled with both motors (while limited to a total of 2kW), while bike paths are run with a single motor that is limited  to 500W for stealth. General riding with speeds averaging 17-MPH provides a range of 40-miles from the 66V / 20-Ah LiFePO4 battery pack.

The bike ended up providing more types of riding opportunities than originally envisioned and preserving the front shifter and derailleur to retain all 21 gears turned out to have been a good choice. It serves as a grocery-getter running with traffic and also travels bike paths largely under pedal power. PAS from a Cycle  Analyst V3 gives additional riding options.

Overall the bike has a retro look with balloon tires, old-school headlight, reproduction vintage Lucas  motorcycle  turn signals, a round motor cycle mirror, and of course, the trademark Mundo luggage rack. The gear motors are inconspicuous and wiring is routed through the top tube giving the bike a clean appearance. Bike path encounters find most people unaware that the bike is powered.

Yuba Mundo V4

Alan liked the Mundo and delayed the build a month to get one of the first V4.0 units (rather than the V3.3).  It weighs 4.5-lb less and has the space behind the seat-tube opened up for mounting components. To soften the  hardtail ride, the bike is equipped with 2.35-inch Schwalbe “Fat Frank” tires, a wide Sunlite “Cloud-9″ cruiser saddle, and a Thudbuster-LT suspension seat-post…worth every penny.

For reasons of strength, Yuba upgraded their later Mundo models with a tubular fork to replace the earlier bladed fork. Although Alan’s bike has had no problems in 7500 miles, he has a new Mundo tubular fork in hand for a winter replacement project – just to keep ahead of any issues that might arise from prolonged FWD and disk brake stresses.

Motors

Geared hub-motors are appealing for 2WD because the internal freewheel allows the wheel to spin unpowered without drag (unlike direct drive motors) – a big plus not only for pedaling, but also for running on a single motor. A YouTube video of a dual gear-motor Big Dummy chewing up hills pretty much sealed the deal and Alan went the gear-motor route. He settled on dual BMC V2S motors from Ilia at http://www.ebikessf.com mounted to identical 26” Sun Mammoth rims.

High volts in a torquey geared hub means Alan used two side-by-side torque-arms.

The stock BMC phase wiring is terminated shortly after exiting the axles with Anderson Power-Pole connectors so the wheels can be easily dismounted for service. 10-Ga marine wire is used from those connectors to the controllers. JST connectors are used for the hall signals.

[editor: We do not recommend direct-drive motors for the front forks on any build for a variety of reasons.  However, for the rear motor of a dual-motor build, a direct-drive motor is a good choice. We also want to point out  that a DD motor on the rear can provide the option of regen-braking, and also near-silent one-motor operation  when desired.]

Controls and Controllers

The bike uses a single Magura throttle to run both controllers via a Cycle Analyst V3 (CA) with power for both controllers routed through a single external Cycle Analyst shunt. Throttle power is drawn from the CA and the CA Throttle Out signal is run in parallel to both controllers. The identical motor/controller/wheel/tire  configuration makes the 2WD implementation straightforward since the two identical drive systems share the load and power equally in all situations – the single Cycle Analyst is unaware it is controlling two motors.

This comprehensive electrical system qualifies to be an electric Moped that is legal to run in traffic, if you ever wanted to register a similar E-bike.

Two operator switches allow on-the-fly selection of either motor (or both) and provide three power levels – all implemented using the Cycle Analyst. With two motors selected the three maximum power levels are 3300/2000/1000 watts but with only a single motor selected the levels are automatically cut in half to 1650/1000/500 watts. The CA ‘Power Throttle’ configuration scales power over the full range of throttle motion for any motor/power combination. Operation is simple and CA does the heavy lifting behind the scenes.

Even with 12-FETs each, these two programmable and adjustable Lyen controllers fit well under the Mundo’s welded cargo rack. Welded cargo racks never work their way loose or squeak.

The original 2011 build used two Crystalyte 72V / 35A / 12-FET analog controllers (not microprocessor-based) and a Cycle  Analyst V2, but in July of 2012 these were upgraded to Lyen’s 12-FET programmable EB312 controllers (modified for  geared-hub use) and a CA V3.  The V3 has Current/Power throttle and throttle-ramping, which are awesome features. The bike is now extremely smooth off the line and requires no special care to avoid wheel spin-out or to protect the motor gears or freewheels – seizing freewheels had been a problem until ramping arrived with the V3 upgrade.

The recently added 16-magnet PAS, now Alans E-bike has a “no-throttle” option.

A recent addition has been a 16-magnet Pedal Assist Sensor (PAS), with an assist-adjustment knob located as a bar-end. “I confess to having been skeptical about the whole PAS thing, but I am completely won over by the change in riding experience. My favorite rides are on the “Rails to Trails” paths, that have miles of gentle grades. I just dial-in the amount of assist I want and enjoy a throttle-free ride through the woods. Turning the knob to zero will kill the PAS-assist and the bike returns to throttle-only operation.”

Batteries

“I went a safe route with the batteries for this first build and began with a 16S / 2P Headway design (53V /  20-Ah), but ordered enough cells and parts to experiment up to 16S / 3P (53V / 30-Ah). Over a period of months I tried different setups and finally settled on a compromise for weight and range using 20S / 2P (66V / 20-Ah) for a usable total of 1024-WH at 80% discharge. When I’m getting 25WH/mi, this gives a solid 40-mile range.”

Headway are large for the amount of Ah they hold, but where they shine is the high current (C-rate) they provide.

The first battery was built as a pair of series-connected 8S /2P packs made of the 38120 Headway LiFePO4 cells from Manzanita Micro (38mm diameter, 120mm long). The packs were fabricated using stock Headway bus bars and 2-hole plastic spacers. Accidental shorts were minimized by using round insulating washers on the cell ends, cut from thick 40-mil rubber shower curtains.  This configuration evolved into the present dual 10S /2P configuration.

Pep-Boys plastic tool boxes were used as temporary battery boxes and served so well they were never upgraded. 1/4-inch plywood bottoms provide added stiffness and simple wooden blocks serve as spacers to prevent the cells from moving around. A high density foam block is compressed under the box lid to prevent the battery assembly from bouncing in the box due to road vibration and impacts.

Headway also sells the configurable pack assembly components along with their screw-top cells.

On each of the two packs, a 50A MaxiFuse originally replaced a bus bar for pack protection, but after a while Alan noticed the fuseholders had overheated and melted to some degree. They were removed and replaced with bus bars. Newly arrived mini-ANL fuses and holders that use bolted instead of tension contacts will shortly take over the protection job. Meanwhile, the main circuit breaker has worked well, so there is no rush.

One of two 16-cell battery packs, with a large 50A maxi-fuse and a cell-log.

The battery-boxes are supported on the Mundo side-loader bars with decks fabricated of wood-grained Pergo flooring  (MDF core with tough plastic covering on both sides). The exposed MDF edges are sealed with tinted epoxy to make them waterproof. Two inch polyester straps and industrial Velcro hold the boxes in place on the decks.

Charging

Partly because of the initial experiments with various battery configurations, the battery has no Battery Management System (BMS) and uses single cell chargers to ensure a balanced pack on every charge. With a forty mile range, one ride a day followed by a slow overnight charge has worked out well. The charger was fabricated of two 8-outlet power strips holding 16 single-cell Voltphreaks chargers in a  heavy-duty  ACHC5500 “Ape Case” from Amazon. Initial use showed the close side-by-side charger placement caused them to run hot, so a fan was added and every other charger was plugged into a thin pass-though Euro/US outlet adapter to simply raise it up, staggering the heights for better air-circulation.

16 individual 3.2V chargers

The charger case connects to each pack using a Centronics 36-pin connector. Each pack has a switch that turns on CellLogs to read the state-of-charge. There’s not much to say, plug it in and turn it on – all green LEDs means “fully charged”. The cells remain in excellent health after 250 charge cycles.

Electrical System

Alan used a 50A magnetic marine breaker for the main power disconnect switch (Blue Sea model #7230). These types of breakers are very rugged and are intended for high-humidity/salt-air use. They are designed for up to 65V-DC and can handle interruption currents up to 7500A making them virtually indestructible in this application. “They start to trip at 62A and with a couple of controller shorts, the CycleAnalyst never recorded a spike greater than 180A before the breaker switched off”.

The on/off keyswitch (metal box) and the main breaker are at the bottom right, the fuse-panel and horn are at the top.

The 50A breaker has worked flawlessly and tripped so quickly that the 50A Maxi fuses in the battery packs never popped.  “For around $15, I cannot recommend this breaker more highly”. It is not rated for weatherproof use, so Alan mounted it upside-down to discourage water entry. A 5W / 330-Ohm resistor and pushbutton provide a standard pre-charge circuit to prevent arcing when switching on the breaker.

Both the original Crystalyte and the later Lyen controllers have a feature where the logic is powered using an ‘ignition’ wire separately from the main-rail FETs. This allows the logic to be powered down leaving the capacitors connected but essentially drawing no power. The bike uses this feature to support a kill switch and keyswitch.

The keyswitch (mounted near the controllers) connects battery power from the breaker to the low-amp handlebar kill-switch, which then powers the controller ‘ignition wires’. The key can be turned on and then removed so the kill switch provides convenient on/off control, or it can be carried and used to disable the bike from being ridden away. The keyswitch is made for exterior-grade security systems and easily found on eBay for less than $8.

For safely riding in traffic, Alan wanted lights, turn signals, a horn, and strobed “blinky” lights. He decided to use readily available 12V components powered by a DC/DC converter. A Green Galaxy 48V-72V 120W unit from ThunderStruck Motors supplies 10A to power the 12v lighting. The converter requires both the main breaker and keyswitch in the “ON” position to operate. The 66V system can be hard on switch contacts because of arcing, so the keyswitch drives a relay to power the DC/DC converter. The relay is a 48V unit from a golf-cart lighting conversion kit and operates reliably at 66V DC with no problems (carefully read ALL of the details in the original post before attempting any of these mods).

“I wanted a valuable piece of safety gear – a FIAM “freeway blaster” auto horn – one of the loudest non-air-horns available.” A conventional 12V automotive horn relay is driven by the handlebar button. Since horns of this type are just giant interrupting inductors and the electrical noise spikes are beyond huge, the horn uses dedicated (+/-) power lines to the battery (so the rest of the system is unaffected). A 1N4006 diode is soldered across the horn terminals as a snubber. The horn body must be must be mounted so that it can vibrate freely for maximum loudness, and so is just mounted loosely with a nylock on the mounting stud”

Lights

In addition to conventional headlight, taillight, and turn signals, Alan added daylight-visible strobe lights. “I didn’t want toy LED strobes with replaceable batteries, I wanted 12V you-can-see-me-at-100-yards-in-daylight mega blasters.” The headlight is a generic 4-inch bobber motorcycle unit with a cylindrical “bullet” shape (as opposed to teardrop) that offers a lot of interior room for mounting electrical components and uses a 55W halogen H4 bulb.

A well thought out  front light assembly

The rear light is a 6-inch oval Optronics STL72RK LED tail/brake light used for trucks/trailers. The taillight portion is wired to the headlight power. The much brighter brake light portion is not used a brake light but is instead used as a rear strobe.

The tail-light assembly

The front strobe is a single round truck side-light with a 2-inch diameter clear lens and 4 amber LEDs. There are a variety of these available, and Alan found the brightest by far was a generic Chinese unit  with four LEDs with individual dish reflectors behind each one [link]. The front and rear LED lights are strobed by an LSC-100B continuous pulsing strobe module [link]. The module is only $5 and about the size of a pack of gum. It flashes four times rapidly, pauses, and then flashes  again, etc.

To get brightness and side-visibility, the turn signals are incandescent 23W reproductions of classic motorcycle units with domed lens. The turn signals are driven by a common 3-pin auto flasher that is tucked inside the headlight housing along with the strobe module. All the lights came with isolated ground wires, except the turn signals which were converted to 2-wire operation (socket not grounded to the frame). “Unfortunately, I sometimes left the turn-signals on after making a turn and so added a dashboard LED.  The LED was too far from my normal line of sight and didn’t work out well, so I finally settled on a small 72-db Piezo beeper that is simply wired across the LED indicator. Much like the clicker in a car, it solved the problem.”

All the front lights are attached to a custom box that is mounted to the head-tube of the frame by two standard  aluminum/stainless-steel saddle-clamps from DX-Engineering. The U-bolts are covered with  heat-shrink to protect the paint. Although the box is fairly inconspicuous, a larger size would have made construction and wiring easier.

For an off-the-shelf motorcycle-style switch assembly, Alan chose the K&S Technologies 9-pin model #12-0055CN.  Although it has a plastic body, it is narrow (which helps the crowded handlebars) and has good quality internal switches. This controls lights, horn, and turn signals…while a toggle on the dashboard controls the strobes.

Brakes

The stock Mundo V-brakes are upgraded front and rear to Avid BB7 185mm disc brakes. “They work  great and the easy adjustment certainly lived up to the reviews. This was a huge improvement, and well worth the  trouble.”  However, the BB7 185mm does not install properly in the rear using the special Yuba adapter which is made for a 160mm disc. Here’s a link to a work-around that Alan used.

Other

The front motor uses two stacked Ampedbikes torque-arms (1/4” total thickness) on one side. These are very cool and will align with almost anything; the teeth on the inner disc are tiny to allow fine adjustment of the arm angle, but you can also flip the disc over to get a ½ tooth rotation for ‘in-between’ cases.

The shaft flats on the front motor are only 17mm in diameter and the drop-outs on the Mundo are the common 14mm, so the 1.5mm shaft shoulder could easily damage the drop-outs when tightened down. Thin stainless-steel washers are placed inside of the dropouts to catch the shoulder and spread the load over a larger dropout area.

Mounting the rear motor was a nightmare because of the oversize Mundo 14mm rear axle. At the time of this build, [ES member] Kiwi had not yet designed his spiffy rear torque-plates for the Mundo V4. The Kiwi plates are highly recommended, but here is the method Alan used instead. Front and rear  torque arms have been overbuilt, but the small extra cost and effort was worth it for the peace of mind. After 7500 miles, they haven’t budged, even with 1700W peaks per motor.

To help make pedaling possible at higher speeds, the crankset has been upgraded from the original 42-32-24 to a Shimano 52-42-30. With the rear motor fitted with a DNP 11T-32T freewheel, pedaling cadence is comfortable at 30-MPH and workable into the upper 30’s.

At recent addition is a temperature sensor on the front motor that uses the Cycle Analyst V3 for power rollback on overheating. Because of the difficulty of installing a sensor in the BMC motor and pulling new axle wiring, Alan tried an experiment that involved drilling a small diameter hole lengthwise in the axle. This allowed him to position a thermistor deep inside the motor. Although not as quickly responsive as a sensor on the windings, it gives reliable results where temperatures rise slowly and a minute or so of lag is acceptable. This has worked out well and required no bike down-time for the upgrade.

All custom metalwork used 1/8th inch thick 5052-T6 aluminum sheet (slightly thinner 3/32-inch should be adequate and easier to cut and form). Cutting was done with a common tablesaw fitted with a $70 Freud LU77M010 non-ferrous blade which gave clean effortless cuts. A recent post suggested the more affordable Oshlun SBNF-120120 would work just as well ($55 on Amazon). Simple pop-rivets fastened the pieces together and nut-serts/riv-nuts provided threaded mounts.

Alan scratched the screen of his original Cycle Analyst with just a casual wipe when it was covered with trail grit. When he upgraded to the V3 he picked up a ZAGG “Invisible Shield” screen protector kit made for a smart-phone screen. Trimmed to size, it works great! Highly recommended.

The Abus wheel-lock

Although he carries an Abus hardened lock and chain,  Alan wanted a more convenient lighter duty lock as well. “For some time I wanted a Dutch-style frame-lock so I could just run into a store quickly. Since the bike is about 150-lbs and 6 feet long, it would be hard to lift or carry away. I chose the ABUS Amparo 48550 SP/LH, which has a key that can be removed when unlocked.”  This lock is a hit. It’s super easy to use, and although it’s not suitable for high security, it has its place and fills many of Alan’s frequent locking needs very nicely.

Final Assessment

“In general. I couldn’t be happier. This thing is super fun, climbs steep hills like crazy, and the 2WD has gotten me home without incident, even with a couple of controller failures. This bike is heavy and perhaps more like a moped, but is still easy to pedal on the flat. I’m happy to have the turn signals on a daily basis, and the high power blinky’s have been a spectacular success for getting the attention of car drivers. It was sometimes hard not to hurry the build and get riding, but the result has a nice production feel that was worth the extra attention.”

_________________________________________________________________

I usually need more pics than what builders originally posted, but Alan has provided quite a few more pics than what I could fit in this article. To see all of the pics, and read even more details about this amazingly professional Mundo, go to his build thread here.

Philistines Yuba http://endless-sphere.com/forums/viewtopic.php?f=6&t=30679

Kiwi’s Yubas http://endless-sphere.com/forums/viewtopic.php?f=6&t=26413

kiwi’s torque-plate thread (Yuba conversion parts) http://endless-sphere.com/forums/viewtopic.php?f=31&t=31881

This months custom build is from Croatia, in Eastern Europe next to the beautiful Adriatic Sea. Zlatko Vidić is a mechanical engineer and when he decided to make an electric bike, he wanted something that would be distinctive, and also reminiscent of the race motorcycles from 1930-’36.

With the full-suspension frame with the weight of the battery centrally located and mounted low, the Mental Manno handles very well.

By the time he had become interested in E-bikes around 2008, the best looking frames were only 3D concepts, and the existing E-bikes didn’t interest him. A close friend (ES member HAL9000v2.0) was the designer of the Greyborg E-bike, and he challenged Zlatko to design his own frame. Most of Zlatkos riding is in the city, and he spent months studying each part that he was designing, so the result would perform well in city riding, but still have as much of the eye-catching style that he visualized in his mind.

Zlatko, with his finished creation.

He knew he wanted a 2WD E-bike, and that was why he also had to design a strong front suspension, since he felt existing forks were not strong enough to safely handle the forces he anticipated using. He chose the girder style, which is what many classic motorcycles from the early days used. A girder fork does not have the extra long stroke you would want for an off-road E-bike, but for street use it performs perfectly. Since he made it himself, the Cromoly steel drop-outs are much stronger than he would ever need (in case a customer wants a more powerful motor on the front).

Although the classic steel girder style forks are an old design, you can see how strong it is from this close-up. Also notice the beefy gusset just behind the head-tube.

Since he was going to use two hub-motors, he did not need large hubs to have adequate power, and the mid-sized hubs he chose resembled the drum brakes of the classic motorcycles he loves. The throttle always operates the rear hub, and the front hub can be switched on for better acceleration, or to help spread out the motor-heat of hill-climbing. The motorcycles from that era did not have disc brakes, so he had two discs custom-made to look like they are part of the hubs.

The brakes are Gatorbrake 6-piston hydraulic units, with a 203mm disc on the front and 160mm on the rear.

Zlatko uses Computer-Aided-Design (CAD) software in his job, so he used that to work out the prototype versions of the frame. A friend of his has experience with Finite-Element-Analysis (FEA), and they used that to test the mechanical stresses on the initial design, to improve it while it was still just on a computer screen.

His cousin is a professional welder, and with the two of them working together, they tackled the next phase of the operation. They carefully cut and bent the Cromoly steel tubing to match the full-size drawings. But…with both of them being very busy at work and both having families…this part took six months to get it perfect, and work out the issues that arose.

The multiple front lights and leather-rimmed goggles add to the retro look of this E-bikes image, and the leather Brookes saddle is the perfect final touch. The red-white-blue “roundel” is an insignia from WWII RAF aircraft.

After he was finally satisfied with the form of the frame, he disassembled it and took the parts to the paint shop. Then…the emotional moment arrived when the paint was done and he was finally able to assemble all the parts. It ended up taking a year of passion and hard work to get it just the way he wanted it. He thought you would have to be a “crazy man” to spend that much time on something, so he named it the “Mental Manno“.

The long journey that took him from only a dream to a finished masterpiece…was an incredible learning experience. However, when Zlatko was proudly showing his achievement to his son Vito, the 5-year old said “Dad, the bike is nice, but there is no seat for me, so this is not good?!” Zlatko thought about this, and decided that…now he will have to design a 2-seat E-bike! 

The family dog takes a rest after a busy morning of chasing E-bikes.

So far he has sold one bare Mental Manno frame, and this original prototype shown here is also for sale. The price for the complete fully outfitted E-bike is 3500-Euro’s (roughly $4,760 at today’s rates). So, if you are interested, contact ES member “Dred”.  The design and production company Zelena Vozila (also from Croatia) is considering carrying the Mental Manno frame as a product. They are the producers of the extra high-power hubmotor called the Cromotor, and they are partners in the production of the Greyp E-bike frame, which is the most powerful E-bike for sale to the public.

You can see the screen of the CycleAnalyst, which is the best E-bike computer available. From this angle you can also see the sliding bushing built into the seat-tube, which keeps the rear suspension linkage aligned.

A 360W geared hubmotor may not seem very powerful, but since there are two of them, and they are run at 48V, it climbs hills very well! The system provides 25-MPH with the motors alone, and 27-MPH when the rider adds pedaling.

This well thought-out frame shape easily holds a very significant battery pack of high-quality LiFePO4 cells from A123. The 48V pack is also a very large 20-Ah, which equals a fantastic 960 Watt-Hours (WH). Zlatko has calculated that he can get as much as 37 miles on a single charge, and so far he has taken it 28 miles without pedaling.

_____________________________________________________________________________

Every journey begins with the first steps…

The rear drop-outs were drawn on a computer screen and then water-jetted from plate steel.

TIG-welding is the best type of welding, and provides a very professional result.

Using precise full-scale drawings helped the process at every step along the way.

The classic girder fork takes shape.

The central housing will hold the battery, the charger, and the two controllers. The hot ends of the controllers are exposed to the air for improved cooling, but I actually like the way it looks.

You can see the craftsmanship and care in Zlatkos methods. He test-fits all the parts at each step to ensure the shape and fit is perfect.

Notice the rear suspension pivot is concentric with the bottom-bracket, this simplifies chain-growth issues when the rear suspension moves. Also, the rear drop-outs are bolted on to allow a customer to shim the width to their particular rear wheel axle (or hub motor). Once properly sized, the customer can then have it welded permanently at a local shop, if wanted.

The parts are back from the paint shop, and the assembly begins! The bottom bracket crankset is a German Schlumpf internally-geared 2-speed drive.

Modern shock absorbers are much better than the ones from the 1930′s, so this E-bike is a fusion of classic style and modern performance.

Scwalbe “Fat Franks” are the balloon tires of choice for classic reproductions, and they can be ordered in several different colors.

Sometimes, a show bike is a “trailer princess”, but Zlatko actually rides his beautiful creation often.

He has embroidered shirts at his website…available in red, white, and the blue shown here.

When the weather is this nice, why go to work in a car?

Here is the build-thread for the Mental Manno.

And here is Zlatko’s website.

This is an awesome All-Wheel-Drive E-bike, and it is also a folder so that it can be carried onto a train for day-trips to the mountains. It has been designed and built by a brilliant guy named Ben, and we are already quite familiar with him, because…he is also the builder of the the “Dogati” Super E-bike.

Ben has a home in very hilly Taiwan, and in particular there is a hill leading up to his home that is unusually steep. In fact, the inspiration for this bike came from an incident when Ben was riding Dogati up that very hill when returning to his home, and in a brief moment of using too much power…he flipped the bike! While resting from an injury that happened during that fall…he wondered if the extra traction from having an AWD E-bike would help him climb extreme hills.

In the pic below, the desk-top machine in the top left is a CNC mill for cutting the shape of custom metal parts, for those times when Ben has a great idea and doesn’t want to wait for a shop to make a part and ship it to him.

Bens “Dogati” Super Electric Bike, and the his new Duty Cycle AWD.

_____________________________________________________________

FRAME

Once Ben had decided he wanted to build a new AWD project, the next decision he had to consider was, which frame? He enjoys taking day trips to the nearby mountains on the train, and bringing a full-sized E-bike had proven to be problematic in the past, but…the idea occurred to him that maybe a full-sized folding bike might work well.

After a comprehensive search, he settled on the Montague Paratrooper. Most folding frames are not as strong as their one-piece version, but the Paratrooper is the strongest folding frame available anywhere. The strength of this frame was a deciding factor, but it’s also nice that the well-designed folding mechanism allows it to be deployed or stowed in less than 20-seconds without any tools.

Be aware that there are many cheap clones of the Paratrooper frame that are easy to find on the web for purchase. Although they look similar, they will not be as strong as an authentic Montague Paratrooper.

The Montague Paratrooper bicycle in the folded position, with it’s travel bag.

_____________________________________________________________

BATTERY

Bens Duty Cycle AWD is nice enough for us to write about it just as it is, but I am really blown away by his DIY battery. Ben wanted to design and document his take on a DIY pack made from the increasingly popular 18650 format cell. These cylindrical cells (found inside cordless tool batteries), are now available in high current models that are not made from the risky LiPo (which has previously been the popular battery chemistry for high performance).

He chose the excellent NCR18650PD cell from Panasonic, and then settled on a 14S / 7P configuration. If charged to 4.10V per cell, a pack configured of sub-packs (with 14 cell groups each) in Series (14S) would be 57.4V when fully charged. Part of this decision was because Paul at em3ev.com can provide an excellent Battery Management System (BMS) for a 14S pack.

This Panasonic cell has 2900-mAh per cell, so when the pack is configured with seven cells in each Paralleled group (7P), this surprisingly small pack has an incredible 20.3-Ah. So, 57V X 20-Ah = an awesome 1140-Watt Hours (WH) of capacity. Our experience has shown us that if a rider adds mild pedaling half the time (which is normal), a geared hub E-bike uses about 20-WH per mile.

Using that as a measuring stick, this 1140-WH pack should average 50-miles (80 km/H). That sounds like a pretty outrageous claim for such a small pack, but…this exceptional cell is now the primary cell used by the Tesla Car company, and that should be all the testimonial we would need.

Ben modeled the pack during the design phase using the popular program Solidworks.

Ben used the common black plastic cell-spacers that snap together, and they make forming an odd-shaped pack easier. The thin wires are for balance-charging each 7-cell paralleled sub-pack. The amber colored film is Kapton tape, which is a final layer of non-conductive protection against shorts.

The final touch was adding a hard plastic shell to protect the pack from the minor bumps that are a normal part of life.

Ben knew he wanted a triangle shape for his battery pack, but the dimensions of a triangle can vary widely. The pack size and specific layout of his cells match a specific heavy-duty bag made by Revelate, and it was designed to match frames from Salsa Cycles. This particular bag is the “El Mariachi“.

A triangle frame bag from Revelate, designed for Salsa bicycles.

_____________________________________________________________

ANTI-THEFT PACK LOCK

Ben has been thinking about a battery pack anti-theft lock for a long time. High-end battery packs can cost as much as $1,000, so…theft protection is no small concern. He recently stumbled across a key-locking seat-post clamp during his searches, which was designed to protect bicyclists from having their expensive saddles stolen.

Ben realized that if a cylindrical post-stub (the same diameter as a seat-tube) was bolted under his top-tube, this clamp could be re-purposed to act as a pack lock. He ordered two large 35mm diameter seat-tube clamps to experiment with, and the results worked fantastic!

Here’s a close-up of the key-lock seat-tube clamps which have been re-purposed as battery pack locks.

In the pic on the left, Ben inserted an 8mm Rivnut into the bottom of the top-tube, and he then bolted a 22mm diameter aluminum post onto that Rivnut. In the right pic, Ben made a 22mm to 35mm bushing that is bolted to the battery pack, and the locking seat-post clamp has a side-inserted screw to hold them together. Two sets of these clamps completes a solid battery attachment and anti-theft system.

_____________________________________________________________

FORKS

Ben replaced the stock forks with a Marzocchi DJ1. Since this fork uses a “through-axle”, he just enlarged the slot and made a 20mm adapter sleeve to fit over the 17mm diameter MAC axle. The fork’s axle-clamping bolt is not strong enough to resist the motors’ torque so he added a set-screw through the top. The wheel is still easy to remove for fixing flats and replacing tires, wires and all.

Here’s a close-up of the custom axle-sleeve that allows a stock MAC axle to fit into an upgraded suspension fork that normally takes a heavy-duty “pass-through” axle.

_____________________________________________________________

The MOTORS

Ben chose two of the MAC geared hubs from em3ev.com. If the name em3ev.com sounds familiar to our readers, an increasing number of builds are using components from this respected supplier. He is now our number-one suggestion for high current batteries that are NOT LiPo.

The MAC geared hub is well-known around ES, and its performance has earned it the right to be the most-often suggested kit for the majority of new E-bike enthusiasts. Geared hubs are smaller and lighter for a given torque, compared to the slightly less expensive direct-drive (DD) hubs.

For a dual-motor set-up, geared hubs have the feature of a built-in freewheel, and this alleviates several issues that would affect the bike if you used two DD hubs. The fact that these motors are light and they freewheel…it makes it much easier for those times when you will pedal the bike without power.

Now that you’ve decided to use two geared hub-motors, why choose the MAC? The less-expensive Bafang-BPM is one of the most commonly sold geared hubs on the planet, and it is roughly the same diameter as the MAC. However, the BPM’s stator is 17mm wide, while the MAC’s is 22mm wide. This means the MAC is capable of roughly 25% more power, and…even if you run the MAC at a lower power, the larger copper mass of the MAC means it would run cooler than the BPM at the same power levels.

If you want a geared hub in the largest size (like the MAC), you might also consider the eZee from ebikes.ca, or the BMC (which was used by Teklektik for his dual-motor Mundo). Both of those motors are also excellent choices.

One of the benefits of buying a MAC from Paul at em3ev.com is that…you have the option to pay a little extra for an upgraded MAC, which has a temperature sensor installed from the factory, thinner laminations that raise the motors efficiency, and thicker phase wires to handle more amps than the standard style.

Like most modern hubs these days, the MAC allows the use of a large disc brake on the front, which is highly recommended.

Ben initially chose dual 8-Turn (8T) MACs, which provided 60-kph (37-MPH) at 57V. Once he had two of these motors, they didn’t seem to struggle at all with the loads he was putting on them, so he swapped-in two 6T MACs which provide a faster 70-kph (43-MPH). Be aware that a single MAC 6T/8T would struggle on steep hills at 57V, but TWO of them is an entirely different calculation.

The MAC is well-known to survive 1,500W peaks as long as the occasional cruise-phase of about half that wattage allows the motor to cool down between hills. Once you add a second motor to the calculation, your E-bike has the copper mass to be able to use 3,000W of peak power.

And…by going to 57V, Ben can achieve a 3,000W peak from a single battery pack by only drawing 53A. This is an important calculation, because by designing the system to work well at only 53A from each paralleled sub-pack of seven cells (7P), each individual cell only has to provide a temporary peak of 8 amps (these cells are rated for 10A peak). At only 8 amps per cell, Ben was not restricted to using only high current cells, and he was able to choose a high quality cell that provides an awesome 2900-mAh of extra high range per each cell in his parallel sub-packs.

For 3,000W at 57V, the battery must provide 53A, but the MAC motors are only sipping a mere 27A each.

_____________________________________________________________

CONCLUSION

This is the third dual motor build we have featured (the others are the Mental Manno and Teklektiks Mundo), and all three have tried a variety of options…and then evolved into a common configuration. All three use two identical geared hubs. They use a single throttle, a single battery…but they also use dual controllers.

The dual programmable Lyen 12-FET controllers are rated for 40A peaks each, so two of them can handle 80A before controller heat becomes an issue. Under the loads Ben is using, they both stay cool (30A peak each for a total of 60A, and perhaps 10A continuous). This allowed Ben to mount both controllers in a bag behind the seat without any danger of overheating.

This set-up can use a temporary peak of 3,000W, and to equal that performance with a single motor, Nicobie’s eTownie and also Rodgahs Big Hit both used a rear-wheel ventilated Crystalyte H3525 at 100V. Both approaches to achieving a reliable 3,000W of performance have been proven to work, but splitting that amount of power between two motors and two controllers…it can have some benefits that are worthy of consideration.

It’s pretty amazing how much range you can get from these high-quality authentic Panasonic cells. Also, by mounting the batteries weight in the center and putting the motor weight split between two of them at each end, this E-bike has a very balanced feel when riding.

When only pedaling (as rare as that may be with a high-powered E-bike) the geared hubs will freewheel. Also, with the dual motors, you have the option of using a single smaller motor, which can help your range on flat land. One of the biggest benefits is the system redundancy…if one motor or controller ever has an issue, you can power home on the remaining components. This may be a vital characteristic in a very hilly community.

And of course, in wet weather or snow & sand, the added traction of AWD cannot be equaled by a single motor E-bike, no matter how much power it may have.

Ben wrote to me that he recently swapped-in fatter tires: “One day my buddy (ES member: ghettoracer) and I were ripping down a fairly steep mountain when we encountered some slower scooter/car traffic on a narrow road. After miles of slow drafting we saw an opportunity to pass so we gunned it. After the pass, my friend hit the front brakes a little too hard as we were passing over some gravel and his front end slid out.

He was riding the black Duty Cycle AWD with narrower 1.95″ Schwalbe City Jets. I saw him go down in a split-second and immediately stopped and went back to block any oncoming traffic. Luckily he suffered only a few minor scrapes and bruises. After that incident I went out and bought Schwalbe Big Ben 26 X 2.35″ tyres for the bikes.

They are ebike qualified for speeds up to 75-kph (46-MPH). I learned that a good set of “substantial” tyres is a mandatory requirement when you are running this type of high-power AWD setup. Using 50/50% power distribution, the front wheel has a tendency to spin-out. Next on the to-do list for Duty Cycle will be a variable control for altering the front/rear power distribution…” [this is a feature that Teklektik also added to his dual-motor build]

Here is the original build discussion from endless sphere.

Here’s Bens Duty Cycle AWD with the fatter tires, which provide better traction and a softer ride quality.

“Duty Cycle AWD was born from the need for raw utility, and bred for the balance between man and machine”

- Ben Chiu, Benjamin Button Bikes

_____________________________________________________________

Written by Ron/Spinningmagnets, March 2014

Once a year at the North American Handmade Bike Show (NAHBS, in Charlotte, North Carolina)…custom-made one-of-a-kind bicycles are displayed to show off the builders skill, and to present new ideas for consideration.

At last years 2013 show, the master frame-builder Paul Brodie presented a mid-drive to NAHBS that was the first electric bike to ever be shown there. Paul is the highly regarded instructor for a frame-builders course, which is held at the University of Frasier Valley in British Columbia, Canada. As fate would have it, last year one of his students was the E-bike industry pioneer Justin Lemire-Elmore, owner of ebikes.ca

The 2014 North American Handmade Bicycle Show (NAHBS)

Well, this year…a completely different Paul (Mr Daniels from Ashland, Oregon) presented the second E-bike to ever be shown at a NAHBS event, and it was just as impressive as the previous one. This Paul is already well-known to us, because he put together the winning E-bike that competed at the 2011 Arizona “Death Race“.

Rather than go for max power, Pauls race-bike used a balanced design with a mid-mounted motor driving a left-side chain the the rear wheel. It was light, efficient, and most of all…it was reliable…compared to several more powerful competitors that suffered a melt-down in the middle of the race.

I might be useful to understand that Paul is also an engineer at Brammo electric motorcycles!

Paul Daniels’ race bike from 2011.

Pauls new NAHBS E-bike is a mid-drive, and it is configured to allow the motor to use the bikes gears. This is the ultimate configuration if you like to occasionally climb very steep uphills, or if you live where you are restricted to using low-power (like the 250W power limit in Europe).

If you run the motors power through a freewheeling bottom-bracket, a mid-drive motor may require a lot of reduction, so that the motor RPMs will stay up in the most efficient range while keeping the output of the drive near the approximate 80-RPM cadence of the pedals. If Paul had tried to use a single stage for the entire reduction, it may have required a very large custom sprocket, and even then…the largest fittable size of the sprocket would be a limit on what is possible.

Computer Aided Design (CAD) was used to produce this concept configuration, and this artistic rendering was created by Michael Hritz. This graphic was the inspiration for Paul, who decided that he wanted to make this in real life.

Paul chose a two-stage reduction using a primary belt-drive, and a secondary chain. This style of reduction has been showing up a lot these past two years. By splitting the total RPM reduction into two stages, the primary can be a very quiet belt-drive, but the more highly loaded secondary drive can be a narrow and strong chain.

When the higher-RPM primary has been driven by a chain on other projects, it can produce a lot of noise. And…if the secondary has been tried with a belt, then it becomes the power limit of the drive, and it is also difficult to fit into a BB-drive because of the belt width and the lack of stock pulleys that can be fitted to a BB-crankset.

As it turns out, the belted primary was Paul’s ticket into the event. In spite of the good press that Paul Brodie had generated last year, the NAHBS organizers were reluctant to allow more electric bikes into the event again. Paul Brodie was so well-respected in the custom frame industry, that they couldn’t say no to him last year, but for Paul Daniels…it was fortunate that one of the major sponsors of the event was the Gates corporation, who is promoting their belted drive systems (which are intended to replace the chain to the rear wheel on high-end bicycles).

Paul’s primary belt was part of a motor drive system (instead of a drive-chain replacement), however…that was enough to get the Gates company to lobby on his behalf. The Gates representatives were able to “persuade” NAHBS to allow several electric bike entries with Gates drive belts (some with the famous Bosch drive unit), among the dozens of pedal-bikes using Gates drive-belts.

The motor is a Transmagnetics 4″ diameter unit, and it’s an inrunner (they shed heat well). The stator has 12 poles and the rotor has 8 magnets.

The primary pulleys are 105T / 19T for a 5.5:1 reduction, and the secondary sprockets are 80T / 13T for a 6.1:1 reduction. The total gear reduction from the motor to the crankset is 34:1, and the primary Gates belt is 5mm pitch GT2, 15mm wide. The large 105T pulley started out as an off-the-shelf Karting unit, but it was sliced in half to 17mm wide and the center was modified to fit onto a custom 6-arm spider that attaches the pulley to a flanged freewheel on the jackshaft. The secondary chain is tensioned by an eccentric mount from a tandem parts catalog.

Total weigh is about 38-lbs (17.2 kg), top speed is reported to be 30-MPH (48 kph).

The frame material is 4130 Chrome-Molybdenum steel (CroMoly), which is prized by custom frame builders for several of it’s characteristics. Aluminum frames can develop cracks over time, but Cromoly has a certain amount of “springiness” that allows it to flex. In fact, this entire frame acts a spring of sorts. Certainly not springy enough to be a replacement for suspension, but on a fairly smooth street, a properly shaped CroMoly frame will provide a smoother feel over an aluminum frame, without the extra weight of suspension components.

Cutting a “fish-mouth” with a hole-saw in preparation for assembling the frame-tubes onto a jig.

This is a frame-jig. It will hold the frame pieces together in perfect alignment during the brazing process, since the heat from the brazing torch can cause warping and mis-alignment if precautions are not taken.

With the frame positioned upside-down, Paul is shown finishing the brazed connection between the top-tube and the head-tube. Brazing with MAPP-gas is cheaper, but the hotter Oxy-Acetylene torch (seen here) is faster.

Torch-brazing with C-04 bronze rod is a frequently seen method among custom frame-building artisans. Later, the bronze welds can be sanded perfectly smooth for an incredibly beautiful finish. Brass is also sometimes used for torch-brazing. It is not quite as strong as bronze, but it is easier to smooth-out afterwards.

Paul Looks happy with the results!

Time to take a break, and stretch a little after contorting his body into odd positions to braze all the pieces together properly. Maybe take his fabrication assistant Molly the dog for a walk, to clear his head before powder-coating?

This bike was inspired by the Green Pea Bikes concept, so the color was already decided before the first tube was cut. Since Paul and GPB are both in Ashland Oregon, it was inevitable that they would eventually meet! Powder-coating results in a much tougher finish compared to paint, and this particular shade is RAL-6019.

The 4-inch diameter (102mm) brushless DC motor from Transmagnetics. The inrunner rotor is 50mm in diameter (2-inches). The stator uses the desirably thin 0.35mm laminations, 3-phase, 12 poles, and 8 magnets. As we can see from this pic, it also comes with hall sensors.

The 4-inch diameter motor may seem somewhat small, but the Bafang-BBS02 has shown that an inrunner this size at 48V performs quite well at 750W.

Paul has stated that the pack is 48V and 470-Watt-Hours (WH), which calculates out to 9.8-Ah of battery. This may seem small, but this last year has seen a boom in the selection of available high current batteries, which are coming from the cordless tool industry.

The cells were provided by Farasis, whose focus has been electric motorcycle batteries, so these cells are likely to be high-current capable. Even when used in a low-current application, high-current cells will run cooler, which is always a good thing. The Chemistry is the well-regarded Lithium-based NMC.

Paul states the motor is being run at 48V and a power level of 750W (the US street-legal power limit), so… 750 / 48 = a mere 16A. This means that if you use high-current cells, and only draw 16A at a maximum…even a battery pack this small will never get hot.

Spot-welding the nickel strips that connect the 18650 cylindrical cells in to series and parallel groups. These 40 cells were initially configured to 10S / 4P (36V). After mounting, Paul felt a larger pack would still fit well, so he made a new pack at 13S / 4P.

The final fitting of all the parts…no time to rest! Paul reports that the final two weeks leading up to NAHBS he was only getting four hours of sleep per night in order to make sure that everything was as perfect as it could be. I think the Gates people must be impressed, and certainly the NAHBS people have a better opinion of E-bikes now…

Making sure every detail is just right for the NAHBS display, just before the doors open!

A close-up of the #219 Kart chain secondary drive, and the very quiet Extron composite chainring. Notice the center of the jackshaft axle is not the same center of the cylindrical shell. This is a tandem mount that tensions the secondary chain by rotating the jackshaft inserts.

I must mention that this design is not just a hastily-sketched napkin drawing, made over lunch, that has been brought to life. I have seen too many concept bikes with a stub seat-post above the top-tube, which have no reinforcing gussets…and made just for the sake of creating an artistic “look“. Normally that is bad engineering, even if it does free up the space under the seat to give the motor-drive engineer more freedom.

However…the seat-tube stub in this design is heavily gusseted above and below, and the battery-housing side-plates are structural members, which adds support while still being fairly light. Although the motor-drive resembles a very professional version of the GNG or the BBS02, it is this frame solution that is a truly new idea. (also, the seat-tube stub is short enough that this frame can easily accept a suspension seat post)

We have been very vocal in encouraging the E-bike industry to increase the availability of optional triangle battery shapes. But…this frame sets a new standard for those who wish to design an E-bike specific frame from the ground up. The tidy 470-WH pack is perfectly situated for locating it’s weight. And it’s small size is acceptable for the average one-way commute of most E-bikers.

But…for those who are willing to pay for a larger battery, this frame easily accepts two of the stock batter packs for a 48V / 19.6-Ah pack! It would be more appropriate to provide an optional larger battery that is only half-again as large as the stock pack…somewhere near the size of 14-Ah, but it is nice to know that the frame is not the limit on the size of the battery you could add, and the battery pack options would be the common rectangle-shape (with lots of options available right now).

Bravo, Green Pea Bikes and Paul Daniels…well done!

_______________________________________________________

Here is the home page of Green Pea Bikes.

Here is their Facebook page.

_______________________________________________________

Written by Ron/Spinningmagnets, March 2014

This mid drive build was started way back in 2008, but…it was so ahead of it’s time, it is still awesome by todays standards. Deecanio is the member-name of an endless-sphere.com builder from the UK who created this historic milestone E-bike.

He decided he wanted something completely new and cutting edge. He had read about how the components for Radio-Controlled (RC) aircraft models had grown large enough that they were beginning to be used on electric bikes. RC components can be found that are very powerful, but the reason for their high price is that they are very small, and it is having high power in a small package that he was willing to pay extra for.

Deec likes riding off-road, so he was immediately drawn to the idea of a mid drive system. The RC motor. controller, and reduction might be light, but it would be extra sweet if the modest weight of the drive could be centrally located, and also placed down low for a great balance.

2008 was about the same time that Matt (ES member “recumpense”) was doing a lot of development work to make highly professional mounts and also drive-reductions for Astro Flight motors. His designs are works of machinist art, and he is a pioneer in this field.

Here is a link to his monster yellow trike from 2012.

_______________________________________________________

Motor and Reduction

Early in the design stage, Deec knew he wanted to have a light mid drive. He had owned a powerful rear hub bike before, and although it was fun…when he was in slow uphill technical sections of off-road crawling, the hub would get hot from low RPMs. Also, when he took jumps, he noticed that the extra hub weight in the rear had a noticeable effect on the bikes handling, compared to non-hub bikes.

Matt Schumacher had just started developing high-end RC motor drives that established a new standard of performance and quality. Deec discussed all the options and decided to use an Astro Flight 3210 motor with a dual reduction. The primary reduction would be turning very fast, so Matt recommended that Deec use a belt and pulleys for that, which would run much quieter than a chain.

Deec wanted to keep the drive fairly small, because he didn’t know yet exactly where it was going to be mounted, but he did already know that his Kona Stinky full-suspension frame didn’t have much room anywhere. The primary reduction 60T driven pulley was the smallest one that would allow a White Industries ENO 22T freewheel to fit inside the pulley face (after the 22 teeth are machined off, the factory circumferential slots provided perfect mounting points).

The 17T drive pulley provides a ratio of 60:17, which equals 3.5:1

The Astro 3210 motor with the belted primary reduction. The ENO freewheel has been integrated into the 60T pulley.

This left the secondary reduction to sort out. The drives’ freewheel allows the pedals to drive the bike without also needing to back-drive an un-powered motor. Since the motors’ freewheel was located in the primary drive, this freed-up the secondary chain drive to use the smallest possible drive sprocket.

Deec and Matt had settled on using high-quality #219 Kart chain for the secondary. The secondary reduction turns at a lower speed, but feels more torque, so a narrow and strong chain is appropriate.

The chainring was going to be the maximum diameter possible regardless of the chain pitch, and…the small pitch of the #219 chain allowed the drive sprocket to have the minimum needed 11 teeth in a smaller sprocket than a bicycle-pitch chain (11T+ to avoid the high noise from the “polygonal effect” when using sprockets with 10 teeth or less), and the 80:11 ratio provided a significant 7.3:1 reduction in RPM’s.

The combined primary and secondary reductions (3.5 X 7.3) results in a 25.5:1 reduction in RPMs between the motor and the crankset. The motor chosen is a radial-flux in-runner Astro 3210 “10-Turn”, which has a Kv of 135-RPMs per volt. If the bike is unloaded (with the tires in the air), a Kv of 135 X 48V = 6,480 RPMs!

Ultra-high RPMs are one method to getting high power from a small motor. As a result, these Astro motors make a high-pitched turbine noise when at full power (Here is a video to show the sound). It’s not too loud, but it is definitely not silent. Running 6,480 RPMs through a 25.5:1 reduction will result in the crankset spinning 254 RPMs.

When a bike is driven on the road, it is a rule-of-thumb that the RPMs will be roughly 20% lower than when it is unloaded, but…even at around 200-RPMs (at full throttle) this system was still going to be way too fast to be able to pedal along with it.

_______________________________________________________

The Tiny RC Controller

The largest RC motors are surprisingly powerful when you consider their tiny size, but the RC component where this size difference is the most notable is the controller. Getting peaks of 3,800W from a controller this tiny is expensive.

This is the 2014 version of the 2008 ESC that Deec used. The one pictured is rated for peaks of 160A and also has a cooling fan attached. Adapting tiny RC components to electric bikes requires careful design matching, and in this case…adding extra low-ESR capacitors to the power inputs.

Deec had decided to use the tiny and well-regarded RC Electronic Speed Controller (ESC) from Castle Creations. The 50V max HV-110 (High Voltage, 110A) looked like it would work well, since he intended to give the motor the use of the bikes gears (as opposed to the higher amp-draw peaks from a direct-chain “one speed”). That not only kept the motor RPMs high in order to help with the slow-speed off-road performance, it also reduces the peak amps that are drawn by the controller and pulled from the battery.

______________________________________________________

The Battery

When we talk about a 48-volt battery, that number is sometimes called it’s “nominal” rating. Deec had chosen to use the very safe LiFePO4 chemistry, and in 2008, the high-current cell to get came in a large cylinder from Headway. He arranged for ES member GGoodrum in the USA to build a pack for him to fit the small triangle of his favorite 2004 Kona Stinky frame. But how many cells and how to arrange them?

The average LiFePO4 pack that is called “48V” uses 16 cells in series (16S). If we use the charge profile of 3.6V per cell when fully charged, a 16S pack will actually start at 57.6V, which would damage the 50V ESC as soon as it was plugged in (if you set the Low Voltage Cutoff / LVC at 3.0V per cell, the battery will actually stop at 48.0V). This led GGoodrum to recommend the odd arrangement of using 15 cells (15S), resulting in a user profile between 45.0V when low, up to 54.0V when fully charged.

Here you can see the rear shock absorber on the Kona Stinky takes up some of the frames triangle space. Deec has put the charger and also the BMS in a metal box with a fan to keep them cool, and at this early stage in the bikes development, he has to remove the side panel to hook up the charger.

There is a small voltage safety margin in the design of the ESC he had chosen, and 15S of LiFePO4 (equalling 54V max) has worked out so far (though we don’t recommend it due to voltage spikes). Deec added more low-ESR capacitors to the ESC input to help suppress voltage ripple to hopefully keep the ESC as safe as it could be.

Once the custom battery was built for the central triangle of Deec’s Kona, that severely limited the options concerning exactly where he could mount the drive on the frame. This may have seemed like putting the horse before the cart, but…this type of design was very new in 2008, and enthusiasm drove everyone involved to make the first steps before the entire plan was solidified.

______________________________________________________

The Freewheeling Crankset

There is a type of bicycle called a trials bike. For a variety of reasons, many of the riders of these acrobatic bicycles (like Danny MacAskill) have embraced the option of having the bicycles chainring freewheel instead of the rear wheel. Because of this…there is a readily available selection of right-side crankarms with freewheel threads machined into them.

Here is an example of a threaded boss on a right side crankarm, in order to allow a freewheel to be attached there instead of the rear wheel.

These last two years, mid drives in this configuration have become common, but back in 2008…this was an uncommon solution to making a non-hub E-bike. If two chainrings are mounted to the freewheeling crankset, a motor can drive one of them, while the other one drives the rear wheel. Deec considered a variety of options (like the dual-parallel right-side drive on Roy’s eCortina), but eventually made the commitment to a freewheeling crank with dual chainrings.

Since the drives secondary reduction was definitely going to be #219 Kart chain, a custom adapter disc was machined to connect the 42T bicycle chainring and 80T Kart chainring to the flanged White Industries ENO freewheel. This is the same heavy-duty brand that was integrated into the primary reduction driven pulley seen above.

Deec had a machine shop fabricate a custom disk adapter to connect the 42T chainring and the 80T #219 Kart chainring to the freewheeling crank. The composite Extron chainring shown is only $20, and it runs quieter than steel.

Matt designed his dual-stage drives so that the central tube clamps allow the two halves to rotate, and this makes the drives’ shape more adjustable for different frames.

Deec used heavy-duty “Echo” brand trials crank arms with an ENO freewheel as the basis of his freewheeling crankset. Using chain for the secondary reduction is appropriate because chain is narrow and very strong. This Karting #219 chain can handle 10-HP+

______________________________________________________

Mounting the drive

The obvious place to mount the drive was just in front of the bottom bracket, but Deec initially feared that when crawling over large rocks and logs, that the drive might be damaged. This led to weeks of discussion over various other contorted possibilities. He briefly considered mounting the drive behind the seat-tube, but that required a switch to a smaller 20-inch wheel (which was OK), but the smaller wheel meant that the pedals were closer to the ground. In the end, he had to finally admit that the location just in front of the bottom bracket was the best compromise.

However, when contemplating an all-new frame design, Haibike has recently addressed this concern by designing an off-road frame that wraps under the mid drive.

A left side view of the Astro mid drive.

This build kept the bike narrow so it remains easy to pedal. Also, by keeping the weight centralized, the wheels stay as light as possible which helps the handling and feel of the bike on jumps.

_______________________________________________________

Giving the motor three speeds

When you have a motor-driven system with a broad power range, you don’t need as many gears to dramatically improve the motors’ performance, but how many is optimal? If your user-profile involves using only the motor most of the time, giving the motor 9 speeds might involve frequent shifting to get to the desired gear at any given moment, but…too few gears will limit your options.

Miles’ eMoulton and Roy’s eCortina have both decided that giving the motor three gears is the best compromise, and Deecanio agreed. There have been several builds where someone had used an Internally Geared Hub (IGH), but a sudden application of high power will sometimes break them.

Miles’ build was designed around efficiency and lightness, but Roy wanted high power, and Roy found that using external sprockets (with a common derailleur) can take more abuse than an IGH. Deec built up a freehub rear wheel, but instead of the 9-speed cluster, he used three single-speed cogs (along with spacers) to contrive a 3-speed sprocket-set.

Applying too much power might still break some of the parts, but the splined track cogs are much more affordable to replace (compared to a new IGH), and high-powered builds have posted that excessive power only causes the chain to loudly “skip” over the cogs, which makes a “ratcheting” noise. Be aware that if you want to try this, you might need to adapt the derailleur to accept a slightly wider chain (1/8″ vs 3/32″, referring to the width of the chain rollers and the sprockets)

This is a close-up of a splined freehub. They can accept as many as 9 sprockets, and Deec used three single-speed splined cogs to make it a very robust 3-speed that is shifted by a derailleur.

The drive as shown here used a 42T drive chainring, with 34T/22T/11T sprockets on a freehub-equipped rear wheel (vs a common multi-sprocket freewheel). Splined “single speed conversion” sprockets can be found on the web, and Surly is one popular source. The bike is geared slow (by using a smallish 42T chainring), and the top speeds in each gear are only 17, 23, 28-MPH (27, 37, 45-kph). These lower speeds work well for Deecs off-roading style.

“…I was hitting peaks the other day of around 80A and 3850W. These peaks lasted just a few seconds, but I repeated it often…maybe 10 times over a 5 minute period. I didn’t have my temperature widget with me, but my “calibrated” thumb said about 170F (76C). The controller was not hot at all…

…This is with the PWM [Pulse Width Modulation in  the controller] set to 16kHz and the timing set to “Normal”, which means the advance will vary from about 5-10 degrees. I think “Low” timing is 0 to 5 degrees of advance. Bob says his motors like about 10 degrees advance in order to get the max power out of them without excessive heat. I previously had mine set to “Low” timing, and the peaks were lower (about 72A), but the motor temp only got up to 108F (42C), up until I broke the master link on the [bicycle] chain…

… I will leave the PWM set to 13Khz. The difference between 13 and 24khz really was vast as far as temp is concerned – initially a [continuous] 30 second blast [uphill] saw the ESC soar to 176F (80C) whereas now…it barely goes over 140F (60C), and that’s with continuous bursts”

Here is the epic discussion thread on this awesome build. As wonderful as it was in the form shown here, Deec continued experimenting with this build and others. GGoodrum had an Astro 3220 that was far too powerful for the 20-inch wheel it was driving, so Deec and GGoodrum swapped motors and Deec upgraded to the Castle 160A controller (among other experiments…)

_______________________________________________________

Deecanios avatar on the chat forum is Murray Langston, who performed as “The Unknown Comic“

_______________________________________________________

Written by Ron/Spinningmagnets, June 2014

Matt Shumaker really made a name for himself a few years ago by developing high performance electric bikes that used the high-end Astro Flight RC motors. The distinctive feature of his drives were the chunks of billet aluminum that were cut into beautiful and well-designed brackets, which mounted these motors to various bicycle frames. You can see his monster yellow trike here. http://www.electricbike.com/50mph-monster-electric-trike/

Matt had calculated out a lot of variables and optional configurations during the first year he was developing hot rod RC drives for E-bikes. The high-end Astro motors he used have the ability to run at very high RPMs, and to access the extra power that is waiting there, you have to use quite a bit of reduction to get the RPMs back down at the wheel speed.

Something that Matt did on his monster yellow trike is to use a smaller 20-inch driven wheel,which simplified several aspects of the design process, concerning the amount of reduction needed. Since he likes to stick with things that have proven to work well for him, the following bikes also use a 20-inch driven wheel.

I really enjoyed reading through the history of the development of these bikes in Matt’s own words, so I am including a lot more text than I normally would. The process of dialing-in the performance is a lot more subtle than just making the calculations on paper and buying the parts to assemble.

_______________________________________________________

The PK Ripper, April 2009

A few years ago, Matt built up a twin Astro bike that used 20-inch wheels. This bike was an “over the top” hot rod, and he used a PK Ripper frame. It ended up weighing only 45 pounds, and with 14-HP on tap (10,000 watts…not a typo), the bike was very “wheelie prone”.

Matts twin-Astro PK Ripper.

” That [PK Ripper] bike was far more fun than any other bike I have built. However, it was too short (wheelbase) and had no suspension. I have had many requests for another 20-inch build and I began moving in that direction“

______________________________________________________

Diamondback X6, March 2012

“I had this Diamondback X6 frame sitting around (built by Intense Racing back in 1999). This frame was bought for its perfect frame setup. There is room in the triangle for LiPo and a high, round downtube for drive unit mounting. It also has a great swingarm for left side chain clearance. I began doing some calculating and figured out that my X6 frame would work if I used a longer shock (I had one lying around) and flipped the shock linkage upside-down. This would drop the swingarm to the correct level for a 20-inch wheel (to have the proper crank height). So, I took my beat up X6 frame to the powder-coater for some gloss black.

When I re-configured the frame for a 20-inch wheel, a couple of cool things happened. First, the rear end is plenty long, and this is great for a forward CG. It also rotated the frame forward, thus steepening the head tube angle. This sets up the geometry for proper road riding. I think the head tube angle looks a bit too steep. But, the bike handles phenominally like this. The wheelbase is also longer than my Hooligan. This makes the bike far more stable while retaining sharp steering with the steep head tube angle.

A Diamondback X6 modified with 20-inch wheels and longer forks, also with a longer shock to rotate the swingarm down.

The forks are White Brothers Groove 180′s shortened to 4-inch travel for me by White. The brakes are Hope 2-piston units. I may to to a 4-piston up front. We shall see. The wheels are Industry Nine custom items using my 47mm wide rear rim. I have another set of wheels like this that use standard spokes and hubs. I may use those. and save these to put back on the red Hooligan as a pedal-only bike. I have to see how things go with these wheels.

You can see the HUGE amount of room under the down tube for the drive unit and plenty of room for lipo. Four 6S packs will reside inside the frame triangle while I am considering a bunch of 3S packs (configured in 12S layout) on each side of the frame with side covers to protect them. That will keep the overall width reasonable and give me plenty of range.

“The drive will be a [single] 4-turn 3220. This is the most powerful motor I have run that is absolutely 100% reliable. I could go to higher power like a 6-turn Delta, but…that would be a bit too much power and would be a hard on the controller at partial throttle. This setup will be good for a reliable 9,000 watts without any reliability concerns.

I honestly think I will need to dial out the wheelie tendency with the slipper clutch as it is. The bike actually rides wonderfully. I think part of that is the rigidity of the frame, forks and wheels allowing the steep head-tube angle to work. The wheelbase is also longer than a typical 20-inch bike, and the forks are a bit heavy. This slows the steering down a touch. I have ridden it fast no-handed without a problem. My mountainbikes can get the headshake wobbles when I do that, but not this bike.

The original plan was for a single 3220 Astro motor, but a customer bought this bike and moved up to a twin-motor system.

Like I said, it rides wonderfully! The steep head tube angle sharpens the handling that would normally feel sluggish. Whenever I build a bike with wide tires and heavy forks it steers heavy. Not this bike!”

I am getting used to looking at it like this. I wish it was one degree shallower just for “the look”. Remember, small wheels put far less twisting load on the frame and fork. They also flex less by their very nature. Beyond that, disc brakes are far more effective with smaller wheels. Also, small wheels allow much more room in the frame for electric components. This makes small wheels and ideal choice for a dedicated electric bike, or at least a dedicated electric agressive streetbike.

The rear was raised three inches and the front was dropped six inches. That rotates the frame forward. That being said, the head tube angle was far too relaxed for a streetbike previously. I may go to 24-inch wheels in front…and rotate the frame rearward just a touch. But, I really want to stay with the 20s if at all possible.

I need to do some 30+mph testing. It rides awesome at 20-MPH. It corners like a freakin 125cc sportbike. The bike is so freaking stout, that I cannot help but move it in that direction. I want to see how “motorcycle like” I can make it while remaining under 70 pounds. If I have to, I will go up to 80 pounds. But, that would be [battery] pack size dependent. I will start with 1-kWH of battery and see if that is enough for my riding. If not, the weight will go up to add range. But, I am committed to making this a true light streetbike/motorcycle.

I want the chassis, wheels, brakes, electric system, etc to all have headroom I.E. I want to make sure nothing is overstressed. I want to know I can beat on this bike, hit rough pavement or small potholes, do some trail riding, aggressive street riding, and have the bike survive. The wheelbase is about 1200mm (3′ 11″). The head angle is around 71 degrees.

Here are Astro Flight’s most popular RC motors for E-bikes.

This is my new flagship build…[and then a little bit later:] this bike is sold! It was sold to a high-end client who wants it built up with TWO 3220′s. This bike will be built as a wheelie prone 50-MPH monster! The buyer is a crazy, high-powered sportbike guy who wanted the ultimate in an overpowered, yet light weight, wheelie machine. The drive will be two 6-turn Delta 3220′s with as much LiPo as I can fit in the frame. The LiPo will be flanked by large carbon fiber panels on each side. This will be somewhat of a Super-Motard bike. My guess is an overall weight of about 70 pounds or so, with CRAZY power.

The gearing will be set for 65-MPH top speed. The customer only weighs 135 pounds and has a turbo charged Hyabusa. I think his light weight and familiarity with high power will make this a perfect bike for him. His specific request was for 60+mph with insane wheelie capability. He already has this exact drive system geared for 60-MPH on a KMX trike. So, he knows what he is in for.

Big hub motors are capable of huge power too. They also cost less, but…there is a weight penalty, though. Two [Castle Creations] 160s with two of these motors is plenty reliable. I have sold many twin motor systems. The bike is capable of over 20,000 watts total assuming the rider is not thrown off. Honestly, I think about 12,000 watts is the limit before violent wheelies become a problem. The bike will weigh in at under 75 pounds with 24 horsepower. That is a 3 to 1 weight to power ratio. This is the most powerful bike at that weight I have ever built.

A close-up of the twin Astro’s powering the left side of the rear 20-inch wheel.

That is 4mm carbon fiber. It has 25-Ah of LiPo.
Twin motor drive with controllers, frame mounts, etc $3,000
Forks $1,100
Brakes $700
Shock $300
Carbon Fiber $400 (and that is a discounted price)
Wheels $1,100
Bike? (I bought it used, and then stripped and powder-coated it) I have about $600 in the frame alone.

_______________________________________________________

 Cannondale Hooligan, May 2014

“I was in the shop the other day after finishing a bunch of work on customer’s bikes and drive systems, and I began looking at various parts I had laying around the shop. I realized I have a drawer full of LiPo packs (brand new). I have a couple battery boxes, a brand new fan-cooled 5-turn Delta 3220, controllers, throttles, drive parts, frame mounts, sprockets, chains, etc. Then…I glanced at my red (Cannondale) Hooligan that I had setup for mild trials riding {but rarely ride} and I decided to build myself a bike as quickly as possible, and…this is what I came up with!”.

Here are the specs;

Schumaker Technologies V4 drive
5-turn Delta, fan cooled 3220 (12,000 RPM motor)
10-Ah of 12S / 25C LiPo inside CNC-machined battery boxes
Drive unit frame mount clamps used to mount the boxes
Castle Creations Edge HV-160 controller
Simple PWM throttle
18 to 1 ratio from motor to rear wheel
One of my 47mm wide rims on the rear
45 pounds exactly
Seatpost: Thudbuster Long-Travel

If you let a single Astro run up to 10,000-RPM’s, even a motor this small can pop wheelies. Here, the crankset has been upgraded to a larger 5-arm 110-BCD.

I set to building the bike, and all of the wiring, component mounting, and machining a couple small parts. I had spent only 4 hours on the bike and it was finished. I have around 15 miles on it so far. The range is around 10 miles on a charge, with my wheelie riding style.

So, I programmed the controller for throttle response setting of “one”. This reduced the violence of the response, and drastically smoothed out the low speed control.

The bike rides great and is EXPLOSIVE! I have pulled nearly 10,000 watts, according to the data logger. I can run at 30-MPH and then snap-wheelie violently. It actually has way too much power for such a small bike. But, with the throttle response at 1 and a bit of care taken with the throttle, it rides wonderfully.

This bike is very similar to the PK Ripper I built 5 years ago, but it is lighter, faster, and more refined. I cannot believe how easy this bike was to build.

So, I decided to mount a lower set of trials forks, to drop the nose of the bike. This lowered the nose two inches and the bars one inch. Now it is a bit less wheelie-prone and much better handling. It does pull more wattage now…

The stock Hooligan has a lefty fork, but the 1-1/8 inch head tube will accept a variety of suspension forks.

I am getting used to the crazy power. 10,000 watts is a bit on a wild side on a 45-pound 20-inch bike. But, I am settling into it and having fun.

Right now it is geared for just shy of 40-MPH (about 38-MPH). I feel like the bike needs to be geared for at least 45-MPH, or maybe 50-MPH to realize its full potential. It is capable of 15,000 watts peak (battery watts, so maybe 12,000 watts at the rear wheel).

Right now I see two volts of sag at 10,000 watts. So, that is pretty good. These 25C cells rock! Oh, 10-MPH to 35-MPH takes only two seconds if I literally lay over the bars.

It would pull harder if I could keep the front wheel down. Hmm, maybe I should lengthen the wheelbase and add more cells up front, along with lowering the seat. I bet that would make this thing a sport bike.

I geared the bike up a touch. It is now geared for 43-MPH according to the math (I have not timed it yet). Anyway, with this gearing, I was able to increase the throttle response a bit and I am seeing far less wheelie tendency. The bike pulls a consistent 11,700 watts under acceleration now and winds out at (ironically) 11,700 RPM under full load according to the data logger.

The increased gearing was accomplished by changing the pulley ratio on the reduction unit. The problem is, the only way to do this with pulleys I have in stock was to move from 5mm pitch up to 8mm pitch (again based on pulleys I had in stock). I am wondering if this larger pitch is affected by the extremely high RPM the motor pulley is turning. Generally, larger pitch is not as tolerant to high RPM. The belt gets a touch warm, but not hot.

Anyway, the bike is no longer a violent nightmare. Now it runs like a sport bike. It has strong acceleration and is very willing to wheelie, but it is not frightening.

The Castle Creations controller is so small, it’s hard to see. The black boxes hold additional LiPo batteries, and the controller is the small square shape just in front of the seat-tube mounted auxiliary battery pack. The wires from the motor go directly to it.

Oh, the wheelie tendency is prevalent when the throttle is opened hard with the bike at or below around 60% of its top speed. Anything above that speed, I can hit the throttle and the front end get a touch light, but does not automatically wheelie.

I added 15-Ah more LiPo this morning. That makes a total of 25-Ah. This should be good for a 40 mile range if I nurse it, or 30 miles of fun.

With the added weight up front, the bike corners better. It feels more planted. It was far too light before, and that made the handling quite skittish.

I was hoping the added weight would tame a little more of the wheelie tendency. It does a small amount. But, the bike is still very willing to wheelie. However, it is far more controllable now. It feels lot like riding a 600cc class sport bike in first or second gear. If you hit the throttle hard enough, it is very willing to wheelie, but not freakishly so anymore. The weight is 58 pounds at this point.

Well, I can verify the range. I just went for a 10 mile ride averaging 25-MPH and used less than 25% of my pack. So, it looks like 35 miles is my range (leaving a safe margin of capacity in the packs).

I can tell you this thing absolutely NEEDS suspension forks! My hands fell asleep and my wrists took a beating. It is fine for general bashing around, but for any amount of commuting, suspension forks are needed. Also, I need a less insane motor. Every little bump made my wrist turn the throttle a tiny bit and that translated into motor response. That made bumpy road riding require too much concentration. So, I will remove this 12,000-RPM motor in favor of a 7,500-RPM motor and gear it up. That should tone down the craziness.

Of course, the power IS fun.

Matt used two motorcycle mirrors, and a Garmin GPS.

P.S. I just got back in from a fun blast. I pulled 13,200 watts on that run. Also, I only saw 0.7 volt (7/10 of one volt) sag under load. I think I am at the limit of this controller.

My hands do not fall asleep when riding smooth roads. I had the bars three inches higher before. But, the wheelie tendency is far less with them lower. It also corners far better with the lower bars. It is not very comfortable for long rides, though…

Yup, 13,200 watts now. It is a freakin MONSTER! But…it is still ride-able at this point. I ordered a fan-cooled 4-turn wye for it. That should make it possible to wheelie, while being extremely rideable and more efficient.

I am pulling 14,000 watts with it at this point, while geared for 45-MPH. If I cruise at 25-MPH and hit the throttle, it will power wheelie even if I lean forward.

I have a Garmin automotive GPS mounted to the bars and I love it. I have around 100 miles on the bike totally problem free. I have really gotten used to the power, too.

Oh, also, I am using a Meanwell PSC 1000 as a charger running through a Watts Up meter to monitor the charge. This is the best charging solution I have run yet.

I have the throttle response set very low (#2 at this point). That dampens out sharp throttle peaks while retaining ride-ability.

What is funny is that I can achieve 23-WH per mile if I am careful, and still have huge power when I want it. Actually, when I ride the bike without thinking about my range at all, I see 32-WH per mile consistently. That is riding with the occasional power wheelie, a bit of full throttle 45-MPH riding, and some general cruising ending with an overall average of 22 to 24-MPH for the entire ride.

I love this thing…

The large 224mm diameter Hayes front disc, with a Hope hydraulic caliper.

At this point I installed a MRP fork (White Brothers), 224mm Hayes front rotor, Garmin GPS, and motorcycle mirrors. I also have the motor setup to be easily reconfigurable from Delta to Wye. In Wye I see 23-WH per mile. In Delta it is 28 to 32-WH per mile.

I also installed [shorter] 140mm cranks to provide greater ground clearance, and I installed one of my torque limiters to minimize the wild wheelie tendency. The bike has several hundred miles on it so far without a single problem…”

Matt has had good luck with Maxxis Hookworm tires, and the jackshaft output is using a heavy-duty White Industries ENO freewheel.

The original discussion thread for the red Hooligan can be found here.

________________________________________________________

If you like the idea of a 20-inch street fighter, but the Hooligan isn’t quite what you are looking for…I found a frame that has a big rectangle in the main frame for mounting a big pack made from 18650 cells. This bike is called the “Yooniq”

For non-suspension frames, I highly recommend a suspension seat-post.

The Yooniq also uses 20-inch wheels. The head tube might be too long to swap-in a suspension fork, but the long head tube also allows a very large rectangular battery pack to be mounted in the center of the frame.

_______________________________________________________

Written by Ron/Spinningmagnets, July 2014

This mid-drive build features an innovative configuration that makes it easier for a builder to pedal along with the motor if you need to ride at speeds above 30-MPH (48-km/h). It was built by a man named Hannes in Austria (endless-sphere.com username: izeman), and the very professional look and performance of this E-bike is the result of a great deal of research and customization.

A mid drive that powers the bottom bracket’s crankset has proven to be a useful way to give an E-bike’s motor the use of the gears. The common and affordable hub motor kit is essentially a “one speed”, and although they remain an affordable and easy-to-install way to turn a bicycle into an electric…they are not well-suited to long and steep uphills.

If your local hills are relatively mild, a hubmotor may still be your best bet, but…if your hills are unusually long and steep, a hubmotor will not have any time to rest and then shed some of the heat that will be building up inside. There are several benefits to using a mid drive, but hilly off-road riding is the one area where mid-drives really shine, and are worth the extra effort and cost to install and have.

______________________________________________

Crossbreak Style

Back in November of 2012, another builder named Johannes in Germany (ES member: crossbreak), began posting a series of experiments to show that a MAC and a BPM geared hubmotor can be converted from a shell-drive to a shaft-drive. This involved un-pinning the stator from the (normally) stationary axle / shaft, and then connecting the stator core to the aluminum side-plate of the shell. This resulted in a motor of a size and shape that was not available in 2012.

The MAC and BPM motors have been well regarded for quite some time when used as a hubmotor. However, they have a poor heat-shedding path when used on extreme hills. This internal conversion also resulted in a dramatically improved heat-path from the aluminum stator core to the aluminum outer shell for soaking up temporary heat spikes that result from using high amps.

This geared hub-motor conversion was interesting enough by itself, but in the same discussion thread…Johannes also proposed a new chain-drive configuration that had some very specific and useful benefits. Rather than gear-down the motor RPMs to a very slow 80-RPM pedal-cadence…and then immediately gear the chain back up to roughly 300-RPMs at the rear wheel, he proposed to run a chain directly from the motor to the rear wheel (to watch a video of how the 7 gears operate, click here). The pedals would then drive a small second chain from the stock crank-set to a side-by-side freewheel and sprocket on the motor-shaft.

This is the original graphic to show what a “crossbreak style” drive would look like.

Although this may sound like it adds a lot of extra complexity in exchange for a small benefit, arranging the parts this way eliminates the need for a freewheeling crankset. It also allows the rider to pedal along with the motor at fairly high speeds while using a reasonably small and readily available chainring size (with most mid-drives, the rider cannot pedal along fast enough to contribute when the E-bike is above 30-MPH).

Although 60T chainrings do exist (to allow pedaling at higher speeds), they are so large that some frames will not fit one, and going to a very small 11T sprocket on the rear wheels’ gear-set causes a very high loading on each of the five fully-engaged teeth.

Hannes decided to build his E-bike with a converted MAC motor, and he would configure it as a “Crossbreak Style” drive. The MAC geared hub costs more than the BPM, but it also has about 25% more copper mass (and power potential)…and yet it still fits easily between the stock pedals.

_______________________________________________

Which frame?

Hannes knew ahead of time that he would be cutting his chosen frame and welding onto it, so that knowledge allowed him a lot of frame choices. The excellent Kona Entourage was not his first choice, but he found a big sale with last years model in the smaller size for a significant cost savings. The smaller frame was not an issue for him since he would be cutting and extending the frame anyways.

Here is the drawing that he settled on, as a guide.

Planning out the best configuration.

Hannes used stiff fiberboard to make a full-sized mock-up to establish the exact shape and size of parts needed for the battery housing.

The battery housing is designed to hold eight of the Zippy 6S LiPo 5000-mAh bricks (four on each side). The pack is configured for 12 cells in series (12S), and if charged to a conservative 4.10V per cell, the pack will provide 49.2V when fully charged, which is fairly common. At 12S, eight of these will have 20-Ah of range.

Hannes welded up a steel jig to hold the head-tube and seat-tube in perfect alignment while he cuts the frame and then experiments with the custom motor and battery housing.

Here is the finalized plan, with the frame stretched a little, and the added housing in place. Notice the highly customized MAC geared hub-motor at the bottom left, with the spoke flanges removed.

TIG-welding the first parts together,. The aluminum plate he chose was a 3mm thick 7020 alloy.

Even at this rough stage, it is looking VERY good!

Preparing the frame for welding the custom housing onto it, while the jig holds everything in alignment.

After tacking the housing precisely into place, he can solidly fill-in all the joints.

It looks rough now, but it also looks very strong.

The custom housing is very slim, but it still fits two LiPo bricks side-by-side.

Reassembling the parts to make sure everything works just as planned.

Here, he is boxing-in the head-tubes’ neck. Notice the joint re-reinforcements inside the corners also have the threaded holes for attaching the battery housing side-panels.

The custom thick heat-sink for the motors’ side-plate.

One of the two major benefits of the geared hub-motor internal conversion is that the heat-path from the stator now has a solid connection to the motors’ aluminum side-plate on the left. Even though the large housing and the frame were all now part of the motors’ massive aluminum “heat-sponge”, Hannes decided to add an even thicker aluminum plate onto the left side of the motor and mill grooves into its face to make fins. This was one of the visual elements that really makes this particular custom build stand out as exceptional.

The plate is a very fat 15mm thick, and the fins and spaces are both 4mm wide…and 10mm deep.

At every step, it gets a little more wonderful. Once everything is assembled and given a final test, he will ship these parts to the powder-coating shop.

The batteries are being fitted here. Instead of having the connections float in the air, he mounted the connectors to a DIY bus. You can just see a green circuitboard hiding below, that is the Battery Management System (BMS), which will help keep each one of the 48 individual cells healthy and in balance (12S / 4P)

After taking a few hard test runs to ensure everything was working together well, he noticed that the stock MAC shaft (which was modified, of course) was showing damage where the sprocket attached to it (the stock shaft is hollow on that end). Hannes made a new solid shaft from a very high-quality steel, on a lathe.

Everything is back from the powder-coating shop now, and the result is wonderful!

Powder-coating is much tougher than paint, and this close-up shows the type of professional finish that results.

The final assembly of all the parts, and adjusting all the wires and cables.

Hannes’ Kona mid drive. The result is incredibly professional, and this frame has a very comfortable stand-over height.

Just in front of the housing is where Hannes mounted a controller that looks like a well-known Xie-Chang 12-FET controller from Lyen. Its actually a 9-FET that has been slid inside the case to a 12-FET. This allowed him to hide the wiring, since he needed to mount the controller where it would get some air-flow, but this area gets enough dirt that he will be washing it off often. Notice there are no external wires hanging down! They pass directly into the battery housing. Using a 9-FET inside a 12-FET case also made room to insert a DC/DC converter to power the headlights he added.

His data-logging on the Cycle Analyst recorded occasional peaks of 44-amps on the hardest parts of the trails, but since he can select an appropriate gear for the motor to be in, the normal amp-draw is much lower while still providing exceptional performance. The controller uses efficient 3077 FETs, and is solidly attached to the aluminum housing to provide a massive heat-sink.

To test the systems capabilities, he set the battery amps limit to 90A, and the motor phase amps at a 190A with no heat issues, but data-logging has shown he accelerates too quickly for the system to reach this maximum setting. He reports it wheelies quite easily. However, this power level did fry one of the FETs in the controller, and…the MAC motors’ internal “ramped roller” freewheel occasionally jammed into the stuck position. Hannes slowly reduced the battery/phase amps down to 40A/70A, and the bike works quite well now at that setting (48V X 40A = 1920W).

A close-up of the crossbreak configuration in its final form. The motor shaft holds a solid sprocket on the inside, and the well-regarded ACS-Crossfire 13T freewheel on the outside.

Hannes lives in beautiful Vienna, Austria. These are the peaceful hills overlooking the city that he enjoys riding through.

These pictures show a 42T chainring on the crankset, which provides the same pedal-cadence as a conventional drivetrain with a 61T chainring. That proved to be a much slower pedal-cadence than necessary,at his top-speed of 55-km/h (33-MPH) . So, Hannes switched-in a 36T (equal to a conventional 52T). Note that using these small-diameter chainrings also help the bikes’ ground clearance for riding over obstacles.

Having an efficiently designed drivetrain and 20-Ah of battery, Hannes is able to consistently ride hard through the hills for 30 kilometers (20-miles), which he reports is about one solid hour of riding. His range would be much better on a smooth street with him pedaling along to help the battery, but Hannes does not ride this on the streets, since Austria has a 500W power limit on E-bikes. unless, of course, you get an S-pedelec licence (S = Schnell, which is “fast” in German). In the USA, we would call this a moped license, and by a coincidence, the only S-pedelec we have written about so far is also in Austria…Martins Cromotor.

“This bike also has exceptional braking power. It uses Avid Core-R with 4 pistons and 200mm rotors, and this makes it easily controllable at high speed. The suspensions long travel together with the fat tires makes it a plush ride. As you can see, I love this bike!…

…The bike is a real eyecatcher. EVERY biker I met wanted to know how fast, how much, how heavy, what distance…and I only got very positive comments…”

_______________________________________________

Written by Ron/Spinningmagnets, September 2014