[Richard]

So while we are on this topic. If you lose the alternator, and I did once when the AC compressor locked and fried the belt, you can crank the gennie and it will power the engine battery if you merge the batteries.

To get home with a locked AC compressor, I bought shorter belts that would run from the engine pulley to the alternator. I keep those in the spare parts bin just in case.

Chester, in normal operation leave the switch in the center position and it will automatically merge. The switch is wired to activate in from either battery bank. Obviously the solenoid needs power to engage. If the trigger circuit on the solenoid was only wired to activate from one battery bank, and that bank were dead then you would be out of luck. Newell thought of that and wired it to trigger from the house or the chassis bank.