Freebeard: All good on your reveal. I was just holding off.
I think ALL the electronics are inside the battery case. The cable from that case runs directly to the alternator. Just need to supply 12v to turn on the system, I believe.
I'm hoping the low battery feature is what changes the motor phase back to charge phase. According to the Buick car video, when the engine was running, no charge was happening to the 2/3rd charged battery. When the guy did something different, the battery started charging toward full.
All that interlock stuff would not be necessary for us. Just a key switch and pre-charge solenoid/relay.
12 more days until I get to tear into stuff.
Once I get there, I can start hounding salvage yards for a bad battery/electronics unit.