Dave, #1 if you have a 3 way fridge, run it on gas not auto mode.
I have been told that sometimes a wacky circuit board can flip flop in/out of 12 v. mode while in auto mode.
#2. (disconnect one at a time) try to isolate each battery to make sure one battery doesn't have a weak cell.
Individually charge and use one at a time while checking voltage for a few hours. See if there is a difference between the batteries. One weak batt will bring down the good battery.
It happened to me with my AF. One battery was actually weak when used individually. If that's the case, buy a new battery .
You might need to buy two if the other good battery is an older battery. I think two equal batteries would give you most amps.
Good luck , have a safe trip home , Bob
