[MetroMPG]

SW continues...

Right again. It does make sense to omit that interlock if you're the only one who will drive it. Some people (like my mother) have a tendency to step on the gas pedal when turning on a car - that can be bad since there's no engine that must first be started. I believe the interlock is required (in the US) of EV manufacturers but I don't think it applies here.

OK, so back to the ground issue. Your shematic shows the negative connections to the contactor coils with a "chassis ground" symbol but there is no place where that ground actually connects to the negative side of the 36V. I assume those connections go to the point just after the shunt.

I would put a small fuse (1A or less)) on the + side of both the voltmeter and the ammeter. It's just a precaution and won't affect their accuracy.

Also you should fuse the controller +36V small wire, and the clock wire (it's better than having burned wires - see I do have a serious side ). The Ammeter fuse may not be needed but if the shunt ever comes loose, it'll save the meter from being fried.

Maybe like this?