Originally posted by noelpolar Fridges are every day here for most with a 4WD that like to go camping etc..... normally 40 to 80 litre capacity.... all can be either a fridge or run at -18c as a freezer..... some have both compartments...... use a small 12v compressor..... generally.... on 12v they draw 3 to 4 amps.... and as a fridge might run on a 50% duty cycle.... as a freezer they tend to be running most of the time.... so 24hr x say 3amps is 72 amp hours of battery draw per day.
The oven draws 10amps or so..... so has about a 120w element.... about 2 hours from cold to heat a load to 160c or so..... with the oven.... I might fill it at 10am and stop for lunch at 12:30 type of thing..... has a thermostat and timer.
When doing this.... most have a second battery added to the car..... isolated in some way from the starter battery..... in my case I have a 100ah Lithium auxiliary battery under the bonnet....... but of course when the vehicle motor is running the alternator runs everything.
I also have a 2kw 240v AC inverter in the car.... so can run our coffee machine from the lithium battery...... that uses about 100amps to run the 1200w 240v element..... but is only for 15 minutes at most..... etc.
I had one colleague who famously drained both batteries in the car by leaving freezer on overnight, not quite sure how but he was somewhat gifted when it came to electrical things.
As for an oven, a South African colleague regularly cooks a small roast when driving across the outback by wrapping it in two layers of tin foil and sticking it in the engine compartment, Obviously it is a little difficult to select how well cooked the meat will be, but by the end of the day it is a hot meal ready and waiting.