Originally Posted by klevin

Actually, no. If you think back to your HS physics classes, you may remember EIR. Current passed through a wire is what leads to heating. Voltage is the means by which we get the current through the wire. So more voltage means more current which means more heating. (and note that voltage times current means power in watts!)

The job of your controller is to control the current going through the motor (usually by voltage modulation) and to vary the frequency for brushless motors, the most common these days. Your motor never directly sees your battery voltage. But the battery voltage may affect how much current (and therefore heat) goes to the motor. It all depends on the controller design and how hard the bike rider drives the system.

There are other factors, like how well your motor is cooled, but you can see there's no simple answer to your question. Does your controller allow you to set a current limit?