RE: Aux Battery
I made my original question way to long and complicated, let me re state it:
If I add an aux battery, with a relay that only connects the two batteries
when charging, and leave all else the same, what have I gained?  The aux
battery is connected to nothing and   the 'fridge is disconnected from both
batteries with the ignition off, same as before.  So what is gained unless
other wiring changes are made to utilize the aux battery?  What am I missing
or misunderstanding about the stock aux battery wiring using the diagrams in
Bentley?