boost solenoid/isolator panel
I took out the rusty panel, sanded it down, painted it and put it back with new circuit breakers and boost solenoid. This morning, I checked the battery voltage (boost switch on all night) at the dash and it showed 13+v instead of 10, and the engine turned over and started quickly. Bonus was that the dash fan switches now work properly, where I could not change the speed from low previously. Nice when things work out.