12v Fridge - reliability?

**sande005** · 12-30-2021, 12:47 PM

Went RV shopping yesterday with a friend, as I know a bit more than he did. He really wants a 17MKE, but was put off on the new ones coming only with a 12v reefer. He boondocks a lot, and likes the option to run off of gas for his first solid body camper.
The salesman (of course) gave the whole pitch about the advantages, and that with the factory solar it was easy to run the fridge on battery for a week (!) We saw through that, but at least started to think about the possibility with bigger batteries and more solar...

However, I wandered off to the service/parts area while he talked to the salesperson, and jokingly asked the service manager about how tough a job it would be to pull out my existing combo fridge, and put in a 12v. He said "I don't care if it was only just removing two screws...I'd never do it. I've never warranty replaced more fridges than I have with those over the last several months." Hmmm, looks like my friend will be shopping for slightly used models....

Anyone else have feedback about reliability of the 12v fridges??

**Second Chance** · 12-30-2021, 01:01 PM

@huntr70 would likely have some information on this...

Rob

**huntr70** · 12-31-2021, 09:28 AM

They have been more reliable than the LP versions. They will run just as long while boondocking as the LP version. Still need 12 volt to run the LP circuit board. More efficient and since they are compressor driven, only run when needed, not all the time.

**Hoopy Frood** · 12-31-2021, 09:34 AM

Are you saying a 12V compressor fridge will run just as long as an absorption fridge with the same battery/ies? I thought the battery draw would be greater with the compressor as well as the control board.

**goducks14** · 12-31-2021, 10:50 AM

I have a 12V GE fridge in my SOB TT. I had an issue with it early on and had a GE mobile tech come to my house to check it out. He said that, at least my GE, was about as uncomplicated as you can get. Basically it's just a compressor and that's it. There's only 2 other components and that's the temp control unit and the control module on the rear bottom. He said those items mostly never fail and are $ cheap to replace. The compressor is simple as well but if it goes (which is rare) then the fridge is toast. I paid $950 in 2019 for it and got a 3 year warranty. It's also a 10 cu.ft vs 8 cu.ft. We've used it a lot since then and it's been flawless.
My 12V fridge only has two cheap items that can break vs an absorption fridge has the 12V circuit, the cooling tubes, and the gas flame portion. All of which are sometimes hard to figure out. No need to add more fans for cooling and if buying new then no hole in the roof.
Mine is run on 400W of solar and I have 4 GC batteries. To be fair I already had the solar and batteries before my Norcold tanked after 1.5 years. I also don't know what the minimum amount of solar I'd need to just run the fridge as it's always ran on 400W's.
I didn't want to deal with the complexities of another absorption fridge so for $600 less I went 12V.
I think there's some junk 12V fridges out there for sure but IMO anything's better than absorption.
FWIW I have my TT at my house when not camping. With just the fridge running on sunny to partly cloudy days my batteries stay full charged 24/7. They get down to 12.41 average at night and peak in the morning when my Victron bulks at 14.6. It cycles that way everyday. It's only when I add my 12V TV, Dish receiver 2000W inverter and stand alone hard drive that my battery consumption out paces my solar.
I see other newer brands of 12V fridges are on the market now and many are more efficient than mine and if my GE tanks I'll still go 12V or take a hard look at some of the residential fridges. Some have much lower consumption than mine. My GE is really, as the tech said a throwback to the past like in the 70's when things were super simple. Not like the newer bling stuff out today. Think of it as owning a 2006 5.9 Cummins vs a 2020 Cummins with 100X's more complexity.
In closing I will say that RV sales people will sell you your own shoes back to you if they could. 12V fridges aren't the end all to RV fridges but they can be a good alternative if you know what you're getting into before hand.

**Redapple63** · 12-31-2021, 02:55 PM

I think the primary differences between the three different types in energy usage is pretty significant, with the gas electric being the lowest consumer (not withstanding other potential issues), with the 12volt compressor style next and the residential as the largest energy consumer of the group.

All have the good and bad associated and it is that set of things that helps each of us determine the best for our application.

I believe the gas electric only needs good 12v for the control board and an ample supply of propane. They sip both which is why many boondockers like them despite the long list of downsides. I believe these may use maybe 10-20 ah per day of battery and 60lns of propane could last several weeks or longer.

12 volt compressor style refrigerators consume 20-50 ah daily and though they require more energy, they function far better and more consistent than the traditional gas electric. You will need more than a single 12volt battery to boondock with this style of refrigerator, and solar is a great supplemental power source for your batteries.

Finally, residential style refrigerators typically are larger, better built and run the best of the three, but consume the most energy, and, require an inverter which represents larger upfront or conversion costs and added complexity. These devices can consume as much as 100 ah daily. There are some upsides though, typically the cost of the refrigerator is far less than the equivalent gas electric or 12v compressor. That helps with conversion costs. Solar here is also a great supplement to charge batteries. Another downside is you need a large enough inverter and enough battery to get you through each charge cycle and good solar to carry the batteries daily.

Hope this helps.

Bill

**xrated** · 12-31-2021, 07:42 PM

I will making a trip to JC Refrigeration in the spring to get my Norcold 2118 converted over to their 12 volt compressors. The unit that they build and sell for that model will come with two 12V compressors for a total amp draw of 10.8 amps when it is running. I'm also building a 4 cell LFP battery that is rated at 304 AHs and it's pretty common to run a LFP down to 10% SOC without doing any damage to the battery. So 304 x .9 = 273 AHs. If you divide the 273 by the 10.8 amps that the unit draws when running, you come up with approx. 25 hours of run time. So if the refrigerator ran steady, without cycling on and off as needed, that would be 25 hours of steady run time on a single LFP battery before requiring it be recharged back up to 100% or so of SOC. We all know that refrigerators do not.....or should not have to run steadily, they cycle on and off as the thermostat requires to keep temperature at the setpoint. So let's say that it only runs 1/2 hour out of every hour.....now you are looking at 50 hours of run time on that battery....or basically two days. Without constantly opening the door of the fridge or when it if first loaded up with food that isn't already cooled, that 50 hour time should be even more. I'm counting on way more than enough battery to run that fridge for at least a couple of days without having to charge the battery. The fact that we don't really boondock, almost ensures that we will have zero issues regarding battery reserve, even during a day that might involve 12 hours of time between unplugging the trailer from shore power, traveling to another campsite, then setting back up and plugging back into shore power. I've already run a dedicated 12V circuit from the battery compartment back to the rear of the refrigerator area, which is in the curbside slide. The power feed is 8/2 cable and the breaker is a 40 amp manual reset type breaker. The wire is obviously oversized for a ~11 amp draw, but that will also help to keep voltage at a good level without any voltage drop at the fridge. Now, all I need is for the battery cells to arrive so that I can complete the battery build, top balance it and then load test it so that I know the true capacity. It seems that some of those CATL cells actually have a bit more capacity than advertised, which would be a nice bonus to be in the 310 - 312 AH range.

**huntindog** · 01-01-2022, 12:29 AM

Originally Posted by xrated

I will making a trip to JC Refrigeration in the spring to get my Norcold 2118 converted over to their 12 volt compressors. The unit that they build and sell for that model will come with two 12V compressors for a total amp draw of 10.8 amps when it is running. I'm also building a 4 cell LFP battery that is rated at 304 AHs and it's pretty common to run a LFP down to 10% SOC without doing any damage to the battery. So 304 x .9 = 273 AHs. If you divide the 273 by the 10.8 amps that the unit draws when running, you come up with approx. 25 hours of run time. So if the refrigerator ran steady, without cycling on and off as needed, that would be 25 hours of steady run time on a single LFP battery before requiring it be recharged back up to 100% or so of SOC. We all know that refrigerators do not.....or should not have to run steadily, they cycle on and off as the thermostat requires to keep temperature at the setpoint. So let's say that it only runs 1/2 hour out of every hour.....now you are looking at 50 hours of run time on that battery....or basically two days. Without constantly opening the door of the fridge or when it if first loaded up with food that isn't already cooled, that 50 hour time should be even more. I'm counting on way more than enough battery to run that fridge for at least a couple of days without having to charge the battery. The fact that we don't really boondock, almost ensures that we will have zero issues regarding battery reserve, even during a day that might involve 12 hours of time between unplugging the trailer from shore power, traveling to another campsite, then setting back up and plugging back into shore power. I've already run a dedicated 12V circuit from the battery compartment back to the rear of the refrigerator area, which is in the curbside slide. The power feed is 8/2 cable and the breaker is a 40 amp manual reset type breaker. The wire is obviously oversized for a ~11 amp draw, but that will also help to keep voltage at a good level without any voltage drop at the fridge. Now, all I need is for the battery cells to arrive so that I can complete the battery build, top balance it and then load test it so that I know the true capacity. It seems that some of those CATL cells actually have a bit more capacity than advertised, which would be a nice bonus to be in the 310 - 312 AH range.

Looking at the JC Refrigeration website, I am pretty sure that the amp draw you quoted is just for the compressor. not the total fridge draw. I know my fridge has some fans in it which will add to that draw. even the light, which would be minamal will add to that.... Total amp draw is what you need to be looking at. I think your plan will work, just not as well as you are thinking

**xrated** · 01-01-2022, 05:24 AM

Originally Posted by huntindog

Looking at the JC Refrigeration website, I am pretty sure that the amp draw you quoted is just for the compressor. not the total fridge draw. I know my fridge has some fans in it which will add to that draw. even the light, which would be minamal will add to that.... Total amp draw is what you need to be looking at. I think your plan will work, just not as well as you are thinking

Fan draw total, counting the inside fans and the aux. fans that I added a few years ago on the inside of the upper vent for the Norcold setup is just under 1 amp, so yes, probably a bit more amperage consumed than I quoted, but still pretty much a negligible amount of current to calculate for. All told, it will be a much better system than the feeble and somewhat useless original Norcold with the absorption type circuit.

**huntindog** · 01-01-2022, 06:44 AM

Originally Posted by xrated

Fan draw total, counting the inside fans and the aux. fans that I added a few years ago on the inside of the upper vent for the Norcold setup is just under 1 amp, so yes, probably a bit more amperage consumed than I quoted, but still pretty much a negligible amount of current to calculate for. All told, it will be a much better system than the feeble and somewhat useless original Norcold with the absorption type circuit.

I believe that I have the same fridge in my 2021 398M. I was somewhat concerned when after ordering it, that I found all the complaints/mods about it here. But I have been quite happy with it. And I am in Phoenix AZ which is about as tough an enviroment as it gets. I do think that they might have changed the fans though, as my fridge draws a lot more than 1 amp. I have not measured it in isolation, but from what I see on the Victron monitor it draws between 3 and 5 amps. I can really hear the fans when they kick on, so they must be pretty powerful
The other reason might be that I never run the fridge with a hot interior. I have done this on all of my coaches. The Momentum is nice in that I can monitor the temps while underway, and if they get to 80 start the generator and AC without stopping. In fact It can even be set to do this automatically. None of my RV fridges would work well with a hot interior.

As for another point. I see that they claim their 12V fridge compressors operate 64% in of the time in their tests with the door closed. This is already more than the 50% you are thinking.. AS the temp rises, and/or the door opens, that 64% figure WILL rise. How much is debatable and depends on conditions, but I do not think you will achieve anywhere near the battery life you are thinking of in actual use.