Posts
360
Joined
3/28/2015
Location
Ashville, OH
US
Edited Date/Time
4/8/2020 8:33pm
Having owned several Altas and built a couple Alta based conversions (see Honda ElectroGrom and ElectroCRGshifterKart) I decided to build something electric that was NOT based on the Alta platform/running gear.
Along with my partner in crime (Instagram Electrobraap) we decided to use commercially available components to replace the extremely rare and expensive Alta parts. We sourced the motor, motor controller, battery management system (BMS), throttle and display from China.
This took quite the effort searching the internet for leads to good components but luckily there's a rather large community of electric "gearheads" with a wealth of knowledge and experience along these same lines. Of course, it still boiled down to selecting the proper component for our specific application, but at least it helped focus us in the right direction. Of course, ordering parts directly from China is another story (and post).
Upon receipt of the various parts it was becoming apparent that China can produce some well designed and well built components! I was impressed.
The BMS, for example, was not only well built but had features my Alta BMS (and I) wished it had! Truly amazing for the price. However, don't get me started regarding user manual and/or documentation.
The motor we selected is very nice, it's the smallest, lightest, and most capable motor we could find ANYWHERE, regardless of price. Truly amazing.
The motor controller looks to be a very robust and capable unit as well. It's not the most sophisticated controller, but it's programable where it counts and has 4 user configurable speed maps selectable on the fly using the supplied handlebar throttle/switch.
The only item we couldn't find to meet our requirements was the battery pack. Oh, although there's plenty of options available they're all mostly junk. And although the quality of build and components gets better outside of China we still couldn't find anything even close to what we wanted.
What we demanded was cutting edge performance, basically a mini version of the highly recognized Alta pack. Very small and lightweight yet powerful with good capacity (range) yet built to take the abuse of constant off road use. Class leading in terms of power, size and capacity densities. The only reasonable choice is a pack that incorporates the small cylindrical 18650 type Li-Ion batteries (cells) from Sony, Panasonic or LG.
Does anyone make such a super pack? The answer is NO they don't, for any price. So I designed and built my own and incorporated some design features not even Alta could match! Based on the exact same cells in the Alta from Panasonic my pack uses 100% COPPER interconnects, not nickel plated tin or alum. I also literally "weld" those copper interconnects to the dozens of cells using a pulsed arc (like micro Tig) process, not cheap spot welding. The result is a pack that beats the Alta in all the important performance metrics!
Why copper, why pulse arc? There's hundreds of cells inside the pack, each requiring electrical connection to one another. That equates to literally over a thousand tiny welds. The electrical resistance of those thousand welds adds up fast! Copper has the least electrical resistance of any metal (not including gold) and results in lower internal pack resistance and better performance. Simple as that. Why doesn't everyone use copper? It's also the most difficult metal to weld so you need expensive equipment and a very labor intensive process so it doesn't lend itself to mass production.
The roller - We picked a small frame bike for our first prototype, a KTM 65. With the advent of the new electric KTM and Husky it's becoming clear that electric is gaining popularity among moto dads/moms and kids alike. It's a great combination with lots of benefits. In addition, the motor/controller combination that we found most desirable had the HP/torque capability to match this class of bike while allowing ample performance headroom to satisfy the adult mini rider as well.
The integration - While the bike didn't exactly assemble itself it was surprising how easy it was to locate and secure the major components like the motor, controller and BMS. Nothing the average guy couldn't do with basic tools. Of course, the battery pack was the biggest challenge but it too eventually integrated very nicely.
The result is what you see below. I still need to completely weatherproof all the electronics and pack but it's a 100% functioning prototype right now. The weight is 140lbs, about 10lbs over stock (with some gas). The weight distribution is about 48/52, right in the ballpark. Top performance right now is regulated but about 70% of the max possible, 10.5HP and 33 ft/lbs. While the HP number isn't spectacular the torque is in the F450 range! It makes for brisk acceleration and unlimited hill climbing potential. Max speed about 50 mph. The battery pack has two times the capacity of the KTM electric for comparison. Of course it can be turned down to match the rider's skill using the map switch but for now we're having too much fun in map 4!
Along with my partner in crime (Instagram Electrobraap) we decided to use commercially available components to replace the extremely rare and expensive Alta parts. We sourced the motor, motor controller, battery management system (BMS), throttle and display from China.
This took quite the effort searching the internet for leads to good components but luckily there's a rather large community of electric "gearheads" with a wealth of knowledge and experience along these same lines. Of course, it still boiled down to selecting the proper component for our specific application, but at least it helped focus us in the right direction. Of course, ordering parts directly from China is another story (and post).
Upon receipt of the various parts it was becoming apparent that China can produce some well designed and well built components! I was impressed.
The BMS, for example, was not only well built but had features my Alta BMS (and I) wished it had! Truly amazing for the price. However, don't get me started regarding user manual and/or documentation.
The motor we selected is very nice, it's the smallest, lightest, and most capable motor we could find ANYWHERE, regardless of price. Truly amazing.
The motor controller looks to be a very robust and capable unit as well. It's not the most sophisticated controller, but it's programable where it counts and has 4 user configurable speed maps selectable on the fly using the supplied handlebar throttle/switch.
The only item we couldn't find to meet our requirements was the battery pack. Oh, although there's plenty of options available they're all mostly junk. And although the quality of build and components gets better outside of China we still couldn't find anything even close to what we wanted.
What we demanded was cutting edge performance, basically a mini version of the highly recognized Alta pack. Very small and lightweight yet powerful with good capacity (range) yet built to take the abuse of constant off road use. Class leading in terms of power, size and capacity densities. The only reasonable choice is a pack that incorporates the small cylindrical 18650 type Li-Ion batteries (cells) from Sony, Panasonic or LG.
Does anyone make such a super pack? The answer is NO they don't, for any price. So I designed and built my own and incorporated some design features not even Alta could match! Based on the exact same cells in the Alta from Panasonic my pack uses 100% COPPER interconnects, not nickel plated tin or alum. I also literally "weld" those copper interconnects to the dozens of cells using a pulsed arc (like micro Tig) process, not cheap spot welding. The result is a pack that beats the Alta in all the important performance metrics!
Why copper, why pulse arc? There's hundreds of cells inside the pack, each requiring electrical connection to one another. That equates to literally over a thousand tiny welds. The electrical resistance of those thousand welds adds up fast! Copper has the least electrical resistance of any metal (not including gold) and results in lower internal pack resistance and better performance. Simple as that. Why doesn't everyone use copper? It's also the most difficult metal to weld so you need expensive equipment and a very labor intensive process so it doesn't lend itself to mass production.
The roller - We picked a small frame bike for our first prototype, a KTM 65. With the advent of the new electric KTM and Husky it's becoming clear that electric is gaining popularity among moto dads/moms and kids alike. It's a great combination with lots of benefits. In addition, the motor/controller combination that we found most desirable had the HP/torque capability to match this class of bike while allowing ample performance headroom to satisfy the adult mini rider as well.
The integration - While the bike didn't exactly assemble itself it was surprising how easy it was to locate and secure the major components like the motor, controller and BMS. Nothing the average guy couldn't do with basic tools. Of course, the battery pack was the biggest challenge but it too eventually integrated very nicely.
The result is what you see below. I still need to completely weatherproof all the electronics and pack but it's a 100% functioning prototype right now. The weight is 140lbs, about 10lbs over stock (with some gas). The weight distribution is about 48/52, right in the ballpark. Top performance right now is regulated but about 70% of the max possible, 10.5HP and 33 ft/lbs. While the HP number isn't spectacular the torque is in the F450 range! It makes for brisk acceleration and unlimited hill climbing potential. Max speed about 50 mph. The battery pack has two times the capacity of the KTM electric for comparison. Of course it can be turned down to match the rider's skill using the map switch but for now we're having too much fun in map 4!
I wonder if you could use a reduction gear off the output shaft that would allow for a smaller rear sprocket and getting the countershaft sprocket closer to the swingarm pivot?
Yes, a jackshaft would allow a smaller rear sprocket.
I ended up with several large BEV cells recently and was thinking of doing something like this. I’m very curious to know the specs and company you used for the bms and controller.
Post a reply to: KTM65 to electric conversion