I bought an electric bike that uses 24v. It has an internal controller set in epoxy inside the motor casing. Exceeding 24v will fry the controller in short order. I have an unused 36v battery sitting around that I would like to take with me to swap out if the stock (24v) battery runs out of power and strands me. Is there a battery power management board, regulator, or step-down device that would allow me to use the 36v battery? Thank you, in advance, for all input!