On this trip, after 4 days in the bear box, I was down to 40ah or so. Pretty sure I've had it down to 25ah on a trip before. When I first built it, I ran it all the way to 0ah once or twice to test the capacity.
I usually account for 10ah running the fridge overnight while on a trip. That's from shutting the truck off after driving all day until the sun hits the panel in the morning. Inside a house at room temps for all day with no charging, you could probably average 20-25ah for the day, plus or minus. 50ah battery might be good for 2 days?
That’s kind of what I was thinking and with solar in the mix, probably endless with 50ah for my set up.