when my
fridge was 3-way (2-way now) I had to manually select DC operation....the
fridge would only automatically cycle between
propane or AC (when the system sensed AC). It was not possible to "accidentally" drain a
battery....
as far as running the
fridge when the tug is running.....if I'm driving the fridge door is closed and it stays closed.....not much need for cooling with a fridge/freezer unit (and my freezer is "too big"...so I have three 2L bottles of frozen water in there as well....I could go for a LONG time without the fridge running)