Alltrax SR48500 setup

[JohnnieB]

The torque increase going from a 275A stock series drive controller to a 500A aftermarket series drive controller is dictated by the motor rather than the controller. The battery produces Amps, the motor draws amps and the controller limits the number of amps the motor is allowed to draw.

The tricky part is that the faster the armature spins, the fewer amps the motor is capable of drawing, so the torque difference between a controller with a 275A limit and one with a 500 amp limit only occurs at RPMs lower than RPM at which the motor is no longer capable more than 275A at the voltage being applied to it.

For instance, dyno testing of an anonymous aftermarket series wound motor shows it draws 231.4A @ 1808RPM and 291.1A at 1573RPM, so it will draw the max a 275A controller will pass at about 1700RPM, therefore the torque gain will only exist when the motor is spinning less than 1700RPM, which is 7.3MPH on stock height tires and faster on taller tires.

Also, the motor cannot draw the max a 500a controller will pass above about 1100RPM, so the full torque gain isn't felt unless the cart is going less than about 4.3MPH.

Basically, the cart accelerates from a standstill a little quicker and can pull a heavier load at low speed.

The above information applies to series drives only.