itslud said:
I was wondering if I can use 52V battery with 250W gear motor with 48V controller.
If the 48V controller is pulling 20A which equates to 1000W but since the motor is rated 250-500W can I cut/shave shunt controller to lets say 10A and that equals to 520W. Is this ok?
Serious lack of info in this query(Is what you are using a secret?), but here goes.
If we are talking geared mini-motor here, 52V X 20A = 1040 Watts might be a little much, but 52V X 10A = 520 Watts is nowhere near enough.
The 20 A controller might be ok if the rider is careful w/ the throttle. As power goes up w/ mini-geared motors, they start to "hammer", especially w/ square wave controllers. The Hammering is a series of shocks imparted to the motor and can be hard on the nylon gears. If the controller is a KT style sine wave, this combo of components is probably ok. Really hard hitting controllers like an older Grineon or one of Lynn's Mini-Monsters in the 20 to 25 Amp range can really hammer a mini-motor. There is also a risk of melting the phase wires on long uphills, especially if a low-speed range motor (a 201) is not used in a whl. 26" and >.
Another thing is, the LVC (Low Voltage Cut-off) of the 48 V controller will be too low for the Batt. Pack, so the pack needs to have one of it's own.