In reply to magma:
> can anyone explain why e- bike batteies usu have 2 pairs of +/-?
On at least some setups, one pair is for the, say, 36v or whatever output/input to the motor, and the other pair is for the battery management system (motor/charger) which runs at a lower voltage of 5v. Seems to be various number of pins in the connectors possible depending on make.
I have read that even a very minor fault in the BMS stops the whole system from functioning. My guess therefore is if they are there on your system they will be needed for something and the bike motor/battery charger most likely won’t function correctly without them connected.
Post edited at 17:23