I know this is backward from most requests, but I'd like to be able to run a 72volt controller at 36v or 72 volts.
My reason is for testing out the performance of some batteries without having to fork out the $ for two of them.
After testing the battery, I'd get a second and run at 72volts. Also it would be interesting to be able switch back and forth between 36volts 40ah and 72volt 20ah.
Brian
I don't see any problem going down in voltage, other than there might be a voltage cutout built into the controller. You should look for a manual for the controller. Justin at ebikes.ca may be able to help you in this area.
Parts-wise, you should be golden going from 72V to 36V. The higher voltage will just give you more margin on your caps and transistors.
IT WILL RUN
Email Justin at ebikesca and ask him. If your controller model will not run at 36v, he can sell you one that does. Or just try it, if you have any sla or other battery around.
Be the pack leader.
36 volt sla schwinn beach cruiser
36 volt lifepo4 mongoose mtb
24 volt sla + nicad EV Global