Putting it together just involves mounting the electric components on the kart chassis; motor, battery, controller and wiring it all up.
The electric motor has a face mount where as a standard kart frame has a foot mount for the motor. To mount the motor a 90degree angle bracket was made out of 8mm aluminium plate. One side bolts to the motor, the other bolts to the motor mount on the frame.
A small auto timing belt pulley (toothed belt) was fitted to the motor and a large pulley was fitted to the rear axel bolted up to the standard gokart sprocket carrier. It would be possible just to keep the regular kart rear sprocket and fit a chain sprocket to the motor, but chains are more noisy than a belt and we didn't want the quiet buzz of the electric motor drowned out by chain clatter.
The cells were assembled in two rows sitting vertically and a clear acrylic box was made to fit them in. The battery box was just thin enough to fit in the space between the kart seat and the side pod and was bolted to the kart frame using aluminium brackets front and rear. It is taller than the side pod so it sits higher and can be easily seen in the kart.
The controller bolted to the frame of the kart just in front of the motor and a small box in front of the controller houses an on/off switch, forward and revers switch an contractors. The controller has a power feed in from the battery pack, inputs from the battery management (BMS) which can turn the power off if the batteries run too low (or any other battery fault is detected), input from the throttle and sensor inputs from the motor. Three heavy gauge power wires connected directly to the motor.
Probably the most complex part is building the battery pack. Bolting the cells together is easy, but there are 24 BMC cell connectors that must be installed across each cell. Its not that difficult, but you do need to be very careful to follow the wiring diagram correctly or you will damage your BMS.
The throttle cable that normally goes to the carburettor in gas kart is attached to a throttle pot or electronic throttle (see photo). The electronic throttle has a +5V input from the controller and puts out a 0-5V signal back to the controller.
Big Red Button
The big red button is attached directly to the battery pack and can isolate the pack in the event of anything going wrong.
The a small on/off switch in the kart doesn't directly switch on the power to the controller and motor. A small switch operates a contactor (large amperage relay) which switches on the power. The contactor enables low voltage switching in the BMS to turn off the power if required to protect the batteries.