I’m building a 4wd rover with four Pololu 25Dx52L 12v-rated motors and I’m wanting to power them with a 24v battery. I have a Roboclaw 2x15a controller that can easily handle the 24v. I don’t intend on running the motors anywhere near the maximum duty cycle. Will those motors withstand 24v if not pushed beyond about 50% duty cycle?
You should be fine running those motors at a 50% duty cycle from a 24V power source. The inductance of the motors will smooth the duty cycles of the 24V output to effectively be 12V at a 50% duty cycle. Please note that your maximum voltage for a 24 battery at full charge will be above 24V, so you might want to further reduce the duty cycle to account for that maximum voltage.