I mounted the controller (blue) to the frame. I cut a hole in the aluminum and made a grommet out of vacuum hose and silicon glue. The cable are connected to the motor and route up this hole.
I made a little platform for the contactors (relays). I also made a mounting plate for the circuit breaker. A lawnmower actuator line runs through the firewall. I will make a "kill switch" inside of the cab.