Here is my Battery set up, 120 AMP which lives in the Back of my wagon.It charges direct from my alternator.
The Engel fridge draws 2 AMP per hour if running constantly. It cycles on and off. So I can run the fridge for 60 hours before recharge if not running the engine.
I now have a solar panel so no need to crank the Motor if stationary for a while. 5 year warranty on that Battery, it's now 3 years in no problem.