On my fridge, there is a hi/low humidity switch visible when the freezer door is open. If that switch is "on", the fridge pulls 1.5 amps. If you have a single battery that will pull you down below 50% in just a couple of days! By turning it "off" the draw slips to .7 A allowing for 3-4 days before the battery drops to 50%...in theory
All of this is based on my fridge and a single 80AH battery...your milage may vary...
In actual use, I have 3 80AH batteries and the fridge pulls me down 3% of usable capacity per day. I'm guessing the frige cycles off at some time during the night.
Of course it only takes a small portable solar panel to make up for the .7A loss...