Inverter draw from battery for residential fridge

I am trying to figure out a couple things on this. We have gone to Florida and the fridge stayed on for each day of the trip there. So the truck must be recharging the battery as I drive it, but then on the way home, the battery went low (eventually bad) and the inverter shut off. I did go buy a group 27 instead of the group 24 but now I am thinking I should have gotten the 6 volts or a second 12 volt but I am not sure another 12 volt will fit in the space.

ktmrfs wrote:
...now to get run time you will need to take into account the duty cycle of the fridge, what % of the time the compressor is running.

and, of course, that will depend on how efficient the fridge is; how well insulated it is; its operating environment (is the interior of the RV cool, is the wall against which the fridge is installed in direct sunlight, shaded by trees or an awning); how often you open the fridge or freezer doors, etc.

look at the fridge nameplate and look for either the power in watts or max current. If it lists max current multiply by 10 to get inverter draw from 12V

If it lists watts current =watts/12

that will give you a pretty close estimate of max power draw from the batteries.

now to get run time you will need to take into account the duty cycle of the fridge, what % of the time the compressor is running.