I have a 3-way Fridge. Other than testing, I never run it on 12-volts. When my TC is in storage (my home), I run the fridge on 120-volts. When on the road or camping I run the fridge on propane. This has worked well for me for over ten years.
I installed a switch between my truck 12-volt and TC. I leave it off, and would only turn it on in an emergency. Fortunately, I have never needed the truck 12-volt system connected to my TC, but with the switch I have that option. I use only one 100 AH AGM battery in the TC, with 130-watts of solar. I do have the Honda for backup.
