Electric Motorcycle Building:Generation II
The rebuild. Except on steroids.
When my first motorcycle was stolen (has now been recovered!), I was left with nothing. Except...
This battery I had ordered toward the end of 2019 to fit all of the space inside of the stealth bomber frame, with 400 samsung 35E cells total (just over 5kWH!).
Unfortunately, it went unused and had sat in my garage for over a year since it was too wide and impossible to get into the frame due to the sidewalls.
Well, I was going insane without a motorcycle. So, it was time.
The first step was to grind off the sidewalls of a new frame.
Next up was finding front forks. The previous build used heavy duty mountain bike forks, the DNM USD-8. However, this time I went with something a bit more bold.
I found a 2006 KTM 525 front-end on craigslist listed for $200, including the triple tree, forks, brake calliper, hose, and lever. It was too good to pass up, so I bought.
The forks definitely needed heavy cleaning and a fresh paint job on the clamps. To my surprise, the steerer tube was 1-1/8 inch, so it fit perfectly in the bomber head tube.
Since I felt a bit more comfortable with paint at this point, I went ahead and repainted the Brembo brake calliper and reservoir as well.
The controller this time was a Kelly KLS8080h with 600 peak phase amps. I mainly chose this for the 240 continuous phase amps, to push up mountains.
To make this large controller fit onto the bomber frame, I used a drill press to make some new mount holes a little less wide.
With the sidewall being gone, I had to CAD a new one to be bolted to the very edges of the frame around the battery. An old friend of mine had a mill down the road I used.
I then drill pressed bolt holes into the new side walls, painted them, and tapped the bolt holes into the frame.
At this point I started the 12v circuitry and had the headlight housing mounted on the fork, and wired the ct-22 dashboard up as well.
I made a crude wiring diagram to help me along the way of splicing connectors.
As far as getting a front wheel for the KTM front-end, I had it fully built by a moto shop nearby me. I used a 19x1.85in rim and painted the rim, spokes, and hub myself.
With a Michelin Pilot Activ 3.25-19in tire and the 270mm rotor and new oversized bracket, I essentially had supermoto braking.
As far as the rear wheel, I had the same exact setup as before: A QS 273 v3 50h in a 19-1.85in rim.
Just as before, I had to dremel the drop-outs to support the larger axle flats, finishing flat with a file and calliper measurements constantly.
I put the torque washers on the inside area of the swing-arm this time, and tapped in the bolt holes after drill-pressing them in.
Finally, it was time to take the bike off the rope hoisting, and shove the battery in. It was a near perfect fit.
I now had a bomber with >100kmph speeds, 100A continuous battery amps, and up to 600 phase amps to supply torque.
On top of this, the battery was capable of charging at 30A on 240v outlets and EV chargers, thus taking less than an hour to charge nearly 70%.
Even at 150 phase amps, the front end could lift off the ground from a start. Getting this thing to not wheelie took some effort.
We just had one major issue. The battery built by Unit Pack Power had 8awg wire. This was a huge red flag for a "100A" battery.
After some heavy testing, my XT150 connectors melted completely at 90A, and after soldering them back together, a battery cell by the terminal wire entered thermal runaway.
Due to this, I got myself a spot welder, nickel strip, and 2awg wires. I blowtorched solder to bind the wire to nickel strips, then spot welded the strip along the terminal cell groups.
I essentially rebuilt the battery myself with much less resistance to truly support such high current.
And here we are for now! The bike is still being run every day by me and we'll find out if there are any further weak points. As it stands, it's a freeway capable motorcycle with a tonne of torque and decent range, proving about 100km freeway and 130-150km city.
Update May 2021: The motor I ordered for this bike was incorrect winding and only got max right around 100km/h due to its kV rating - somewhere around 800RPM when I requested 1030RPM.
Luckily, my first motorcycle was retrieved after being stolen, and its motor had correct winding. So I swapped the two bikes' motors, since the first motorcycle only maxed around 100km/h by power anyway.
As a result, I have pushed 130km/h thus far on this bike, with a 90A limit on battery amps. Further testing is to be done with more battery amps!
Update 2025:
After building Gen3, I have some notes to give on this build. The battery amps were never limited to 90A.
In Kelly software, the battery amp value is percent of maximum phase amps, that you program. In my case I think that was 550A?
This explains why it had melted leads before the battery re-gauging. The battery current was basically unlimited (495A!).
After the ANT BMS was put in, it had a proper limit set on the BMS side at least, and that was 260A peak.
Thus, the bike's peak power was really around 19kW when accounting for large sag down to ~74v.
June 2021:
Here is a sample of the bike going through Malibu canyon with its new speeds.
You can see in the video that a cargo rack has been added with pannier bags, which will soon be used for extra batteries.
The charger is also now bolted underneath the rack, so it is always onboard.
This battery I had ordered toward the end of 2019 to fit all of the space inside of the stealth bomber frame, with 400 samsung 35E cells total (just over 5kWH!).
Unfortunately, it went unused and had sat in my garage for over a year since it was too wide and impossible to get into the frame due to the sidewalls.
Well, I was going insane without a motorcycle. So, it was time.
The first step was to grind off the sidewalls of a new frame.
Next up was finding front forks. The previous build used heavy duty mountain bike forks, the DNM USD-8. However, this time I went with something a bit more bold.
I found a 2006 KTM 525 front-end on craigslist listed for $200, including the triple tree, forks, brake calliper, hose, and lever. It was too good to pass up, so I bought.
The forks definitely needed heavy cleaning and a fresh paint job on the clamps. To my surprise, the steerer tube was 1-1/8 inch, so it fit perfectly in the bomber head tube.
Since I felt a bit more comfortable with paint at this point, I went ahead and repainted the Brembo brake calliper and reservoir as well.
The controller this time was a Kelly KLS8080h with 600 peak phase amps. I mainly chose this for the 240 continuous phase amps, to push up mountains.
To make this large controller fit onto the bomber frame, I used a drill press to make some new mount holes a little less wide.
With the sidewall being gone, I had to CAD a new one to be bolted to the very edges of the frame around the battery. An old friend of mine had a mill down the road I used.
I then drill pressed bolt holes into the new side walls, painted them, and tapped the bolt holes into the frame.
At this point I started the 12v circuitry and had the headlight housing mounted on the fork, and wired the ct-22 dashboard up as well.
I made a crude wiring diagram to help me along the way of splicing connectors.
As far as getting a front wheel for the KTM front-end, I had it fully built by a moto shop nearby me. I used a 19x1.85in rim and painted the rim, spokes, and hub myself.
With a Michelin Pilot Activ 3.25-19in tire and the 270mm rotor and new oversized bracket, I essentially had supermoto braking.
As far as the rear wheel, I had the same exact setup as before: A QS 273 v3 50h in a 19-1.85in rim.
Just as before, I had to dremel the drop-outs to support the larger axle flats, finishing flat with a file and calliper measurements constantly.
I put the torque washers on the inside area of the swing-arm this time, and tapped in the bolt holes after drill-pressing them in.
Finally, it was time to take the bike off the rope hoisting, and shove the battery in. It was a near perfect fit.
I now had a bomber with >100kmph speeds, 100A continuous battery amps, and up to 600 phase amps to supply torque.
On top of this, the battery was capable of charging at 30A on 240v outlets and EV chargers, thus taking less than an hour to charge nearly 70%.
Even at 150 phase amps, the front end could lift off the ground from a start. Getting this thing to not wheelie took some effort.
We just had one major issue. The battery built by Unit Pack Power had 8awg wire. This was a huge red flag for a "100A" battery.
After some heavy testing, my XT150 connectors melted completely at 90A, and after soldering them back together, a battery cell by the terminal wire entered thermal runaway.
Due to this, I got myself a spot welder, nickel strip, and 2awg wires. I blowtorched solder to bind the wire to nickel strips, then spot welded the strip along the terminal cell groups.
I essentially rebuilt the battery myself with much less resistance to truly support such high current.
And here we are for now! The bike is still being run every day by me and we'll find out if there are any further weak points. As it stands, it's a freeway capable motorcycle with a tonne of torque and decent range, proving about 100km freeway and 130-150km city.
Update May 2021: The motor I ordered for this bike was incorrect winding and only got max right around 100km/h due to its kV rating - somewhere around 800RPM when I requested 1030RPM.
Luckily, my first motorcycle was retrieved after being stolen, and its motor had correct winding. So I swapped the two bikes' motors, since the first motorcycle only maxed around 100km/h by power anyway.
As a result, I have pushed 130km/h thus far on this bike, with a 90A limit on battery amps. Further testing is to be done with more battery amps!
Update 2025:
After building Gen3, I have some notes to give on this build. The battery amps were never limited to 90A.
In Kelly software, the battery amp value is percent of maximum phase amps, that you program. In my case I think that was 550A?
This explains why it had melted leads before the battery re-gauging. The battery current was basically unlimited (495A!).
After the ANT BMS was put in, it had a proper limit set on the BMS side at least, and that was 260A peak.
Thus, the bike's peak power was really around 19kW when accounting for large sag down to ~74v.
June 2021:
Here is a sample of the bike going through Malibu canyon with its new speeds.
You can see in the video that a cargo rack has been added with pannier bags, which will soon be used for extra batteries.
The charger is also now bolted underneath the rack, so it is always onboard.