[piotrsko]

Series motor voltage constraints is oddly enough the gap between commutation segments and corresponding flash over which erodes the comm bar and brushes super fast. Total voltage determines what current you can push and power made. In @Duncan 's case it might zorch if he ever gets to above 75% "on" in the duty cycle at low rpm.

Having said that, realize a motor is an inductive load. The faster it spins, the more back EMF is going to resist forward voltage with zero rpm having the highest current demands. Therefore, it is possible that motor may survive the + 300 volts at redline rpm.

Kostovs with added interpole magnets are tested to survive 300 volts but also have an 8 degree retarded comm timing and do not generate the same levels of HP to prevent zorching

500 lbs isn't that odd, Kostovs are 220 lbs and 500 is about the weight of a 7 liter gasoline engine

 

[piotrsko]

Well in theory for a very short time, you can spin a 500 lb motor with 18650 cells. You can test a 13" using a 12v car battery but that drew 50 amps. I suppose 12v would spin at low rpm a bigger motor, didn't have one to test. Weight of battery kinda correlates to range depending on chemistry. 1/2 ton of FLA don't go as far as 1/2 ton of pouch Lithium.

@Duncan : does your controller have circuitry or software to alter the PWM frequency based on RPM? Soliton does software checks and balances and something Tesseract called a "sanity check" subroutine that limits maximum voltage and current output but I am not sure an igbt failure to "on" would stop full power motor destruction before the mains contactors open.