12v cooler plugged in

Just overnight it shouldn't if you have decent batteries. Leave it plugged in over a weekend and yes it will drain them.

 

over night, no. over the weekend, maybe.

depends on how many and what condition your batteries are in

 

Will the batteries on a flashlight burn out if you leave it on?

 

Same as above. over night you should be ok. Weekends, I wouldn't. When I was with Knight, they would only put 3 batteries in the Volvos. They would constantly drain esaily. Couldn't even run the bunk heater in them for more than 4 hours. The Pete I had, had 4 batts in it. It lasted a lot longer.

 

If you got a low voltage disconnect in your truck it will shut everything down before you drain the batteries so low that you won't be able to start your truck. Mine beeps at me when the batteries get low. The cooler really does use up the batteries but if you run long milage each day you'll be OK for about 18 hours with 4 batteries (in decent shape). But if you're leaving it plugged in all the time and only running a few hundred miles or doing a 34 reset you'll be getting to the point where the LVD will kick in.

 

Vito pretty much covered all of the bases.

Unless i use my microwave the dorm fridge is never unplugged.
Of course, it's all plugged into the inverter, i dont trust the 12 volt appliances.
When i roll daily, all is well. If i sit for a day straight the batteries suffer for sure.

Just keep an eye on your voltage and you'll be fine.

 

I think you need descent batteries. Wimpy batteries will not do good. I have 4 brand new 1100 CCA batteries n I leave my 12V Coleman cooler plugged in all the time 24/7. When I am home for 4 days I leave it plugged in n my truck still starts fine after sitting for 4 days...

 

Add to the fact that most 12v coolers are not designed to run 24/7. Mine runs while I'm driving. I leave it on until I hit the bunk and then unplug it. Everything stays cool and when i get up, I plug it back in. Had it for over a year now with no problems.