Replacing dual batteries......charging issue?

[rayra]

I should at least route the key-activated circuit like to my combiner solenoid thru a dash switch, so I can deliberately decouple in a situation where I know the Aux is depleted. Flip the switch to disable the combiner solenoid, start the vehicle, re-enable for alternator recharging of the Aux / both.
I'd like the Blue Sea setup, but I'm too cheap to buy it. I've only overnighted twice with this vehicle since I bought it. And I'm way too busy to do so the next 6mos with school to do anything about it, or with it.