Can I Really Do This?
Yes! If you have followed me this far, you probably have the desire to learn and the ability to read. The only other thing you need is $5k.
Most motorcycle conversions include an electronic battery management system (BMS). If you don’t use a BMS, you need to make sure you don’t overcharge or undercharge any cell in your battery pack.
The only practical way to do this is to balance the batteries to the same voltage, and therefore state of charge (SOC), and to ensure your charge and discharge limits are conservative so that all cells stay within the normal operating range. And you need to check the cell voltages often enough to verify that the cells are staying balanced.
I’ve been extremely impressed by the uniformity of the Nissan Leaf batteries. They have not drifted at all. And the slope of the discharge curve is much greater than LiFePO4, so it is easier to use voltage as an indication of SOC.
Also, the lower cost of the Leaf batteries may explain why there seem to be folks out there using them without a BMS. It is not as compelling to spend over $500 on a BMS to protect a $1200 Leaf pack as it is to protect a $2500 LiFePO4 pack.
Like most electric motorcycle conversions, and many production electric motorcycles, this one does not incorporate a multiple-gear transmission. There is one front sprocket and one rear sprocket.
It is impossible to do this with an internal combustion engine due to the narrow power and torque bands, but it is an option with electric motors. The benefits are simplicity, reduced weight and cost, and elimination of efficiency losses associated with a transmission.