Is your fridge plugged into the factory power outlet? That one is and always will be powered by the main battery. Most people install a different outlet, connected to the bus bars on the aux batt. If you have already then you have a problem with your system. Mine disconnects exactly as it should.My experience with the Genesis system over the past 4+ years hasn't been quite what you are explaining. My main battery doesn't seem to disconnect when it gets to 12.7 volts and continues to be drained by the 2nd battery. I've experienced a dead main battery several times over the years which I attributed to the fridge/freezer in the back.. All of my aftermarket stuff runs off the 2nd battery, the main battery only powers as it did from stock with no additional connections. Then again, my Optima yellow tops just don't last more than a year to 14 months and both get replaced on a regular basis by optima under warranty for the past 4 years.