We run our fridge on 12V while on the road, however I have installed a relay in line with the 12V source to the fridge. You will find this recommendation the fridge manual. The relay is operated by an extra circuit connected to the ignition wiring in your tow vehicle. When the ignition in the tow vehicle is off the 12V to the fridge is turned off. This avoids running batteries down and avoids running the fridge at a tilt if you park on a slope. There are some that say the latter item is not much of a concern in the newer fridges. I won't argue that point.