My new ARB fridge run test, 6 days of running battery voltage readings

[pods8]

I picked up a new ARB fridge last week and wanted to get a general feel for the power draw it would have on my system before taking it out camping next weekend. So I ran this unscientific baseline test:

The fridge was sitting in the isle on my FWC, which remained closed up during the entire test (ie no vents open), my FWC sits outside. For batteries I'm running (2) PS-62000 6V 210ah batteries in series that are ~2.5yrs old but have been treated nicely.

For a quick thermal load I grabbed (6) 1/2gal jugs of water and threw them inside the fridge. The fridge stayed closed during the entire test which is less realistic but in general one should try to limit how much they're going in/out of these anyways.

Fri @ 6pm with an ambient temperature of 85F I loaded in the jugs and set the fridge to 32F. Both the fridge and my camper were plugged into 120V to bring the fridge temps down on 120V (which would be my normal practice before a trip) and to make sure my batteries were fully topped off.
Fri @ 10pm I unplugged the camper and the fridge was now on 12V; fridge 32F/ambient 72F
Sat @ 8:30am: Fridge 32F/ ambient 61F / batteries 12.85V
Sat @ 3:00pm: Fridge 31F/ ambient 86F / batteries 12.78V
Sat @ 7:30pm: Fridge 32F/ ambient 84F / batteries 12.73V
Sun @ 7:30am: Fridge 32F/ ambient 61F / batteries 12.74V
Sun @ 3:00pm: Fridge 31F/ ambient 77F / batteries 12.70V
Sun @ 7:30pm: Fridge 31F/ ambient 75F / batteries 12.68V
Mon @ 6:00am: Fridge 31F/ ambient 52F / batteries 12.67V
Mon @ 5:00pm: Fridge 32F/ ambient 89F / batteries 12.62V
Tue @ 6:00am: Fridge 32F/ ambient 57F / batteries 12.60V
Tue @ 5:00pm: Fridge 31F/ ambient 89F / batteries 12.51V
Wed @ 6:00am: Fridge 31F/ ambient 58F / batteries 12.49V
Wed @ 5:30pm: Fridge 31F/ ambient 91F / batteries 12.41V
Thur @ 6:00am: Fridge 32F/ ambient 57F / batteries 12.41V
Thur @ 5:00pm: Fridge 32F/ ambient 82F / batteries 12.21V (Fridge was running)
Thur @ 8:00pm: Fridge 32F/ ambient 82F / batteries 12.34V
Ended test.

Needless to say I'm quite comfortable with the battery bank to power draw match-up for easily sitting somewhere for a long weekend without needing to charge up the batteries at all factoring in there still be other users like lights/fans/etc.

 

[overlander]

Good info. So your two batteries in series are dedicated accessory batteries?

My ARB will go into shutdown after 1.5 days on my yellowtop 34 optima dedicated accessory battery here in NC. I have a permanently mounted Batteryminder manager on the frame that is tied into my accessory battery, so on weekends or long stays I plug in.

My fridge is working a bit harder due to the heatwave. I need window tinting and a fridge cover to help it out. I'm going to add a permanent solar panel on the roof to help extend the aux battery as well in the near future.

Once these dual optima dies, I'll go with Sear Platinum. That should help tremendously, as these optimas just don't last more than a year or so. This Optima is about 2-3 years old, and won't recharge much over 12.3 volt, even the though the starter battery, which is the same yellow top in an isolated system, is still holding a charge over 13volt static all the time.

 

[pods8]

Yes these are 6V in series to make a 12V 210ah battery bank. They are for the camper only and get charged either via a shore power smart charger or a DC-DC smart charger off my truck battery (which is only when the truck is running). They still rest over 13V when fully topped off.

Prior to getting a fridge I had myself convinced I'd definitely need solar once I moved to a compressor fridge but now I'm not thinking it's a much of an issue with a proper battery bank.

 

[1911]

Good data, thanks for posting. I haven't had any problem running my 37 QT ARB for a few days at a time, but it's good to have some hard data.

 

[Ryanmb21]

This is an interesting post. I am wondering how long my fridge can run off my new Sears Die Hard PM 34 (68 amp hours).

 

[4x4junkie]

Good info.

What's the size of your fridge?
I don't s'pose you happened to measure the current drain of the compressor running by chance? (and how often and how long it's run cycles were)?

Edit:
Just noticed this post is over half a year old :Wow1: