Electric Motorcycle - Where to start?


100 mW
Aug 29, 2019
If you want good acceleration torque even as you approach max speed, you'll have to gear it for a higher speed by some amount. I'm not sure exactly how much, but you can use the ebikes.ca motor simulator to get the approximate idea--the torque curve it has will intersect the speed curve at the point you don't get any faster. Change parameters (voltage, current, and/or gear ratio for a middrive) until the torque is still as high as you want it to be while at the maximum speed you want to go.
I'm still not 100% sure if I have the custom motor settings correct, will be digging into J Bjork's posts to compare what they'd used.

Is it the case that motor torque starts decreasing once the supplied voltage reaches half the battery voltage, or did I dream that? if it is true, what's the best terminology to start searching and understanding that with?


Staff member
Aug 17, 2009
Phoenix, AZ, USA, Earth, Sol, Local Bubble, Orion
AFAIK motor torque should be greatest when there is the highest phase current, which is at the lowest possible RPM, since that is when there is the least BEMF generated by the motor's spinning to oppose the incoming phase current. This is the blue line on the graph.

Motor *power*, however, is torque x RPM, so that probably does peak at half the full speed of the motor (which would be at about half the battery voltage, with no load). This is the red line on the graph.