12v Fridge

[mikefic]

I am new to camping. I have a 2021 Kodiak Ultimate 2921 FKDS. It has a 12 v refrigerator. While the camper is plugged into my tow vehicle (2020 Ram 1500), can I run the fridge? I was wondering if I can stock the fridge while driving.

[donzinger]

Yes you can. It will run on 12v and propane. Be sure the switch is in either AUTO or Propane/Gas mode though.

[dsol]

Just keep in mind that you will be using propane when you do this and in some cases it is illegal such as when going through a tunnel of at a gas station. Many debate its danger or lack thereof but that is a different discussion. The bottom line is you can do it.

[mikefic]

Thank you for your help!

[leisuresolar@gmail.com]

RV fridges that are of the gas absorption type work by boiling ammonia. It can boil with LP Gas (with a 12V control board and valve. It can boil with 120V heater (with a 12V control board and valve). In some cases, and this may be your case, it actually has a 12V heater.

If it does have a 12V heater, and you are running it on the 12V setting, then it will pull your batteries dry in no time. The Ram has a peculiar trait where it leaves the 12V line on the 7-way trailer plug hot all the time, even with the key off.

If your fridge is on 12V and you leave the caper plugged into the truck, it will pull your truck batteries dry.

[kimbo@alum.mit.edu]

I keep my fridge running on a 120 volts with a 12 volt inverter on the road. That way I avoid the propane burner blowing out and some MH have had fires caused by fridges on the road. I have an HD alternator and run sperate #6 charging cables to the trailer with a golf cart solenoid activated by the ignition in series as switch to prevent the truck battery from being discharged by the trailer inverter load and battery when the engine is stopped. I use Anderson quick connectors and soft stranded welding cable to connect to the trailer battery. I have a Silverado and discoed the 12 volt line through the 7 pin connector by pulling the fuse.

[leisuresolar@gmail.com]

A 6awg wire properly fused is a great way to charge a trailer while towing. In the RAM (not sure about the Chevy) the trailer brakes and 12V line share the same fuse. So if you pull the 12V fuse for the 7 way plug, you kill the trailer brakes.

I have seen some cases where the trailer has a large battery bank, and when it gets very low, and you start the tow vehicle, the trailer demands so much current that fuses blow, or wires burn (if not properly fused) or alternators overload. Mercedes Sprinter Vans actually requires the upfitter to limit the current to 40A max.

[Race4Beer]

My Kodiak has a straight up 12v, no gas option. I run fine off the vehicle if the charge wire is active in the 7-way plug. My 70Ah battery doesn’t last long if I’m not plugged in to 120v or running the truck.

[Race4Beer]

Originally Posted by leisuresolar@gmail.com

RV fridges that are of the gas absorption type work by boiling ammonia. It can boil with LP Gas (with a 12V control board and valve. It can boil with 120V heater (with a 12V control board and valve). In some cases, and this may be your case, it actually has a 12V heater.

If it does have a 12V heater, and you are running it on the 12V setting, then it will pull your batteries dry in no time. The Ram has a peculiar trait where it leaves the 12V line on the 7-way trailer plug hot all the time, even with the key off.

If your fridge is on 12V and you leave the caper plugged into the truck, it will pull your truck batteries dry.

Many newer trailers are 12v only. My 2021 Kodiak has a 10cubic foot 12v only, no gas option.

[leisuresolar@gmail.com]

My SunLight pop up has an old Dometic 3.5cf 3way fridge. I measured the power draw and consumption while running strictly on 12V (no LP). It drew almost 6A from the battery, at about a 50% duty cycle. That is 72AH per 24 hour day.

I'm sure my 8cf fridge in my 5er draws more, but it doesn't have a 12v boiler. I do know it draws close to 3KWH (250AH at 12V) per day when running on 120VAC.

Compare that to an energy start rated 18cf household fridge at about 1KW per day, not counting losses in the inverter. The new, high efficiency
12/24V compressor fridges (Secop compressor) only use about 600W per day, and run directly off of 12V so no inverter losses.