If your Bigfoot
has a Dometic Americana series or similar model refrigerator
, check the climate control switch located below the control panel in the top of the frame for the freezer compartment. It should be OFF if you are running on battery power only. The climate control is a heater strip in the frame of the unit and consumes quite a bit of power. It is best only to activate the climate control when you are plugged in to shore power, as it will deplete the battery rapidly.
The electronic board in these refrigerators demand about .3-.4 of an amp, or around 8-12 amp-hours per day and will run the battery down eventually, but you should be able to get 4 days or more out of your battery (assuming it is good and of reasonable capacity) with frugal use of lights and water pump.
If you have a propane
detector, it also draws a small amount of power continuously and will kill the battery over a longer period of time.
I agree with Colin, get your battery checked. Discharging a battery below 50% capacity repeatedly will dramatically reduce it's life and should be avoided. If it is weak, replace it with a quality true deep cycle battery of the largest size that will fit. There is very little space in the existing location for a much larger size, but if the battery tray is relocated slightly to the rear a group 31 size battery will squeeze in. I use a Trojan scs225 (130AH capacity) and it has served me well. The newly released Trojan J150 has the same footprint but is taller and offers 150AH - it may also fit but careful measuring would be in order to be sure there was adequate clearance in the fiberglass nacelle.