Help, 2003 Arctic Fox fridge isn’t staying cool when on DC

Quick question - has anyone had this issue with their refrigerator and if so, how can I resolve it?

We were hoping to run the RV fridge on DC electric while driving. We have 200 watts of solar panel and also had a dc/dc charger installed, with (2) 100 amp hr 12v LFA batteries in parallel (200 amp hrs 50% depth of discharge or 100 amp hrs without damaging the life span of the batteries) …

Before we left Thursday afternoon, we had it plugged in on AC the day prior and it was up to temperature when we left. On propane and AC it stays cold (40 degrees F or better) and the items in the freezer remain frozen solid. But, while the freezer seems to be working fine on DC, the temperature of the fridge seems to be running warmer (mid to upper 40s or worse) - I even put one of the frozen solid water bottles in the fridge on the middle shelf, as the temp began rising (which also started to thaw, not surprisingly since it was less than 0 degrees.) But the temp still appeared cool in the fridge, and that frozen bottle didn’t thaw out significantly in the time frame it was on DC and in the fridge, but when we saw the temp on the indoor/outdoor thermometer start to rise towards 50 degrees, we turned it back to propane where it ran fine and we could even decrease the level of the refrigerator temperature (ie - from 9 down to 6.) It was 90 degrees F outside yesterday, but I wouldn’t think that would be the proverbial “straw to break the camels back” so to speak… )

Therefore, my question is: Is this typical - or should it be doable to run this 3 way rv fridge on DC and have it work appropriately? (Prior to having the dc/dc charger installed, we had always run the fridge on propane when driving, but we’ve been taking heed of the reasons why it’s not the best idea and hence why we installed the dc/dc charger in addition to the solar panels. And, just to clarify, we had no issue with keeping the batteries charged with the dc/dc charger and solar panels when we had the fridge running on DC power- we only switched it over to propane because the temp was implying that it was getting too warm in the fridge.)

I’d love to hear others experiences regarding running their 2000 era AF fridge 3 way fridge off DC.

TIA!

Truck Campers

enblethen
Nomad
Aug 21, 2021
Operation on DC will strain to keep it cold.
Why not run it on propane like most RVers?
AnEv942
Nomad
Aug 21, 2021
That has been our experience, fridge will start to warm on extended run time on DC. Mostly due to the 12v heater is less wattage so less btu than gas or AC.

Traveling generally hasn't been an issue once the DC charge is resolved, but will run warmer as the day progresses, especially as outside temps rise. But have never lost food due to temps, once stopped returning to gas or shore brings temps down.
daily_double
Explorer
Aug 21, 2021
What he said
mockturtle
Explorer II
Aug 21, 2021
enblethen wrote:
Operation on DC will strain to keep it cold.
Why not run it on propane like most RVers?

Bingo!
Or get a compressor fridge like mine that's made to run on DC.
KD4UPL
Explorer
Aug 21, 2021
Running a 3 way ref. on DC is a "last resort". I think the 12v element in those things pulls something like 30 amps or so. That's about 360 watts so around double what your solar panels will be producing.
The propane burner is probably around 1,500 BTh per hour which translates to about
440 watts, that is, nearly 50% more than what the DC element will do.
I have no idea how accurate these numbers are for YOUR particular fridge but there should be a plate on it somewhere giving all the details so you can do your own calculations.
Grit_dog
Navigator
Aug 21, 2021
^What he said. To the point that many newer RV absorption refrigerators don’t even have a 12V mode.

Same camper as yours, the only time I ran it in DC mode was if propane had to be turned off, or as a default if the LP blew out going down the highway.
jimh406
Explorer III
Aug 21, 2021
One other thing to keep in mind is that if the fridge isn’t full, it’s harder for them to keep cool. You really can use almost anything to fill it up. Gallons of water etc.
Sjm9911
Explorer
Aug 21, 2021
Dc never works great on the 3 way fridges. Depending on the unit some use a fan mod in the back to help cool it and a fan in the box to distribute the air. If it runs on propane while on the road, I would use that.
riah
Explorer
Aug 22, 2021
OK, thanks every one for your replies!

But, honestly we didn’t experience any issues with the batteries keeping up, as we have a DCDC charger PLUS the 2oo watts of solar…. It was showing our batteries were at 100% with the fridge running on DC! That was my initial concern, that the batteries wouldn’t keep up.

I guess we will just have to keep an eye on it. )It was 90 degrees F so maybe it’s just too much to expect for such warm temps! I guess we can swap it back and forth if we need to.)

The reason I was trying to get away from running the fridge on propane is because we have the electric charging capability and the capacity apparently to run it off the 12v DC and it’s safer than propane; as well as already paid for and therefore free in comparison to the propane, since we planned it to use DC to run the fridge when we’re driving.

But the consensus appears to be that it’s typical behavior apparently to have it warm up over time, which is sort of a bummer as we apparently have the ability to power it well enough as far as the batteries are concerned!
pianotuna
Nomad III
Aug 22, 2021
riah wrote:
OK, thanks every one for your replies!

The biggest issue is voltage drop.

My 3 way fridge works GREAT on 12 volts--so long as I'm plugged into shore power. On batteries only--even though I have 556 amp-hours and 256 watts of solar it doesn't work well at all.

If you want to "fix" the problem, then add a dc to DC charger and set the voltage at 14.8.