Here’s my 500W converted bike with a battery put in a school lunch box with keyed relay inside. I made another torque bar for the other side of the hub that is not as flash as the one that comes with the kit but it is functional. The leads on the controller were just the right size for the bike and I kept the battery leads as short as possible. It works great, plenty of power and I barely need to pedal for any length of time up hills. I reckon a 48 volt controller with a 48 volt batery on a 36 volt hub would really make it go. I dont think it would do the motor any harm provided the duty cycle is kept low. At 65 years of age I still like a bit of excitement!!!