It seems you are confusing amp-hours (ah), which is a measure of capacity (how much juice is in the tank) with amps (current flow) provided to/thru the controller/motor. As long as the controller/motor can handle 36 volts and the battery pack can deliver the amps (10?) required, the pack can be as big as you want (10ah, 20ah, 30ah, etc.) The higher the capacity the further you can go between charges.