I usually go out for three weeks at a time 3 or four times a year.
I have been using an ICECO DUAL ZONE FRIDGE/FREEZER for thee years with absolutely no issues what so ever.
works flawlessly.
In addition: the comments on solar for back up on a dual battery system.
Not so much as we never want to camp/park in the sun we always try to stay in shade so the solar ideal is not a easily a workable plan. ( does work but has its own hurdles) the better resolve is to go with a DC to DC charger in your system your house battery and start battery will always be at full charge with out having to cook yourself in the sun.
I have been using an ICECO DUAL ZONE FRIDGE/FREEZER for thee years with absolutely no issues what so ever.
works flawlessly.
In addition: the comments on solar for back up on a dual battery system.
Not so much as we never want to camp/park in the sun we always try to stay in shade so the solar ideal is not a easily a workable plan. ( does work but has its own hurdles) the better resolve is to go with a DC to DC charger in your system your house battery and start battery will always be at full charge with out having to cook yourself in the sun.