Overnight battery life and mini fridge?

If you're talking about a thermo-electric cooler, and not running anything else like an inverter, you can probably run it 36 hours or probably more and still be able to start okay outside of perhaps real cold temps.

If you have a digital voltage readout, use this as a guide and make note of voltage draw after every 6 or 8 hours. This should give you an idea where you may be getting into trouble (below about 11.0 volts.)

 

Wow, a virgin.
Live and learn.

By that I mean that you should observe how your truck responds to how you use it.
And also, observe it over time.

Batteries wear out over time, so in a couple years they may let you down.

 

A lot of it also depends on outside and inside temps.

Batteries won't get used much as the fridge probably won't turn on much when it's 30 degrees outside.

Expect heavy drainage in peak summer time temps though.

 

What they said. You'll be aight. I've let my truck sit for 5 days with the fridge on and she started right up. These ammonia powered fridges don't draw much at all.

 

Who has an ammonia powered fridge?

You have a sundance in a truck?

By the way, get some ice packs from walmart, freeze them and stick them in the fridge part when you park.

 

I do. Truck and camper. I like how you can run them off propane if you want.

 

If you're worried about running down the batteries,you can get a isolated starting battery. It used to be an option on the Freightliners back in the day.

Checking the volts won't tell you anything. The amps are what turns the starter. If all of your batteries are good then anything below 12v is risking it.

You should also carry a set of heavy duty jumper cables as insurance along with knowing how to hook them up from truck to truck or truck to car.

 

If you do only have 3 batteries then it would last a day or 2 if you not a bunch of other stuff with it.. when one of them batteries starts to go bad tho it is going to be over pretty quick only running 3 instead of 4.. .some of them cheap mega fleets try to get away running 3 batteries and then wonder why all the road calls for jump starts..

 

Snug a 4th batt in there...I've got an 03 FLD using a mini fridge, but i have a factory low voltage warning.