The battery from BMSBattery is different. It has it's own plate, which fixes to any rack. The battery case has two slots so that the battery slides on to the plate and there's a hole in the front into which the lock bolt goes. You could use the battery, but I think, you'd need a new rack and you'd have to re-mount the controller somewhere else, or you could buy a new 9 or 12FET controller at the same time as the battery because they're very cheap without additional postage, and then you can realise the true potential of the motor. You'd need a 20aH battery with the 12 FET controller.