The problem starts when I read about electric motor workings and basically only the current is what determines torque and voltage doesnt even appear in the equations. Then we get a situation like this: 36v*30A=1080w and 72v*30A=2160w, but they both have the same current, so acceleration would be the same?! That cant be right. Where does the extra kilowatt go? It cant be just lost to heat, if anything, higher voltage should be more efficient, not less.
I understand the motor is controlled by pulse width modulation, so 72v with 60A per pulse at 50% duty cycle would equal 36v*30A on average, so we would get the same result as just using normal 36v battery. That solves the mystery for me for the same power output from a higher voltage battery.
But now I want more torque and, as I understand, the only way to do that is to increase Amps. To increase Amps beyond what the classic motor can eat at 36v we need to increase the voltage.. lets say I want double the torque, so double the Amps: 60A. To push 60A I need double the voltage, so 72V, 60A on 100% duty cycle. 72V*60A= whooping 4320w ! But since im "only" getting double torque, where the hell does the extra 2000w go?