Homemade BB Drive Electric Bicycle

This bicycle has a Unite MY1018Z 450W 24V motor attached to the cranks. The motor has a gear reduction built into the motor itself, and there is an addtional 4:1 reduction from the motor to the cranks. I have a special freewheeling crank system that allows the motor to turn the chain and the pedals to remain stationary. I also have a Megarange freewheeling sprocket in which the smallest gear has 14 teeth, and the largest is 34 teeth. This gearing allows for a maximum speed of 28mph. Normal cruising i