Davydd, that is a useful reminder. The fridge is one of the most troublesome things to manage correctly. Turn on 24 hr. before leaving, park only on level spots, or level the vehicle EVERY time, turn from gas to electric and back before and after driving EVERY TIME, remember to lock-latch the door....sigh.
As you said, leave it on electric at your peril when parked for any length of time. (Leave ANYTHING on that draws much power at your peril, especially fans).
My 20' Roadtrek has no solar, officially room for one 80 Ah battery, grudgingly considering uprading to two 100 Ah, which I'm leaning towards, although I'm griping about giving up valuable storage space. No automatic switching available for my old refrigerator, as far as I know. 2 AGMs will provide a little more mental block leeway.
I'll just have to rely on my wife nagging me - she never forgets anything
Did you have a solution in mind?
Hybrid Mode
