Fridge upgrade- absorption to 12v

[DarkClouds]

First post- looking to replace my Dometic Absorption fridge with a 12v compressor fridge. Have any of you upgraded to a newer version and what do you recommend? I currently have a 2017 23FBQ Flying Cloud and the fridge is unreliable. I also want to keep a cold fridge while driving but, don't want to run propane on the road. I have 4x100w panel and 2x100ah lithium batteries.

[4RXLA]

I installed a NovaKool RFU9000 9.1 cubic foot single compressor 110/12 volt and am very happy with it. Freezer is on the bottom in this model.

[field & stream]

The big issue to consider is the far greater electric power usage of compressor fridges vs. absorption fridges. If your style is to be plugged into shore power all (or most) of the time then, in my opinion, it is a no-brainer to get a compressor fridge.
If you mostly camp unplugged then many variables enter the picture.

In your case — with 400w of solar and 200Ah of lithium — you should do fine for many days unplugged as long as you have decent solar gain. Dense shade or overcast will reduce your solar recharging to a fraction of its potential.

There are several very informative threads on this topic. Use the search engine for electric only fridges.

[DarkClouds]

Thanks. I would like to think we will off grid more but, my wife has a preference for full hookup sites so we can run the AC.

[cosmotini]

We have the Norcold 12v 8 cubic ft in our trailer (N8DC). It's been the best refrigerator out of the 5 Airstreams we've owned. It cools down quickly (less than 3 hours) and maintains temps with far less fluctuation than any of the absorption units. It may use more battery power, but I've run mine for well over 24 hrs on the 2 AGM batteries we have without issue or damage to the batteries. I'm sure the 180 watts of solar helped, but I also think it may be more efficient and not run as hard since it isn't dealing with the heat generated by the propane flame. Not positive on that, but just an observation.

[JohnandDonna]

The absorption fridge in our 2020 International 30RB works great. I know a lot of scuttlebutt is about running propane while towing, but a lot of folks have done that for years. And while there may have been the occasional problem experienced by some, same could be said for many things. The only reason I could see to change over is if we went full time upon my retirement. My wife would like more space in the fridge. However from everything I have read, it would be wise to convert over to a lithium battery system due to power needs. That means a new inverter and some serious coin.

[Mike1997]

I still have the original 3way Dometic Royal absorption frig in my Landyacht. The 3rd power source is 9v which is all automatic. Once the motor is started it automatically switches to 9v but it does have an override to run off propane full time if needed. My only issue is the ice maker which is worthless and takes up space. Its one of the "to do" items to remove this summer.

In the trailer units it would seem easy to set up a 9v connection as long as its drawing power from the tow vehicle.

[uncle_bob]

Hi

First question is: What are the exact dimensions of the fridge AS put in *your* trailer?

Next up: How much room is there behind / above / below the fridge?

Why? The compressor fridges like to have vents above and below the fridge. This is a bit different than how the absorption fridges went in.

Yes, this assumes you want to fit the fridge into the existing space with a minimum of hassle. If a major redo of the inside of the trailer is on the list, that opens up the choices. Otherwise, you will need to find a fridge that fits in the space you have.

Best guess is that you will not find something that is a perfect fit. Minor chopping / shimming here or there is not an uncommon part of the "new appliance" process in an RV.

Many things are tangled up in supply chain issues these days. Simply finding a unit that will fit based on a spec on the internet is just the first step. Finding one and getting it shipped to you ( in good shape ...) may or may not be very easy.

Since you are pulling out a propane gizmo some care in playing with the pipes and properly capping them off is part of this. How you deal with / utilize the existing vents and access door is up to you.

Bob

[DarkClouds]

Originally Posted by uncle_bob

Hi

First question is: What are the exact dimensions of the fridge AS put in *your* trailer?

Next up: How much room is there behind / above / below the fridge?

Why? The compressor fridges like to have vents above and below the fridge. This is a bit different than how the absorption fridges went in.

Yes, this assumes you want to fit the fridge into the existing space with a minimum of hassle. If a major redo of the inside of the trailer is on the list, that opens up the choices. Otherwise, you will need to find a fridge that fits in the space you have.

Best guess is that you will not find something that is a perfect fit. Minor chopping / shimming here or there is not an uncommon part of the "new appliance" process in an RV.

Many things are tangled up in supply chain issues these days. Simply finding a unit that will fit based on a spec on the internet is just the first step. Finding one and getting it shipped to you ( in good shape ...) may or may not be very easy.

Since you are pulling out a propane gizmo some care in playing with the pipes and properly capping them off is part of this. How you deal with / utilize the existing vents and access door is up to you.

Bob

Great point, I have decided to pull the whole fridge out and install 3 12v PC fans to replace the 1 jet engine sounding installed fan. The system works, just not well so I am hoping to adjust airflow, baffles, and insulation to improve performance. This will also provide an opportunity to measure the cut out and asses the possibility to replace the unit later.

[field & stream]

Originally Posted by DarkClouds

Great point, I have decided to pull the whole fridge out and install 3 12v PC fans to replace the 1 jet engine sounding installed fan. The system works, just not well so I am hoping to adjust airflow, baffles, and insulation to improve performance. This will also provide an opportunity to measure the cut out and asses the possibility to replace the unit later.

I think this is a wise step in your case. Properly installed and ventilated propane fridges work well in moderate temperatures like on the west coast. I added fans to my 23’ and 16’ and in both cases they improved fridge performance.

I suggest you also google Dometic’s installation guidelines — Airstream is not diligent about following them — and you might find opportunities to improve airflow, primarily by eliminating dead air space.

[ffwilliston]

To answer your question:
In a 2021 Airstream Classic, I switched the absorbsion refrigerator to the same Norcold compressor model that comes standard in the '22 Classic. There ARE significant wood working alterations required, but doable if you have skills and time. Cools much better, naturally. (It ran over four days on AGM batteries; solar may have helped.) Yes, many trailers run safely on propane refrigerators; however, look at the primary causes of travel trailer fires to understand why it is prudent to make the change for safety (along with much better cooling and internal space). You'll gain a little additional outside storage in the space behind the lower vent door.
Also, consider changing to SmartPlugs on your power cable for additional safety (they're now standard on all new Airstreams for that reason).

[1957Custom22]

DarkClouds, your post caught my interest, because I’m nearly finished installing exactly the same electrical capacity you now have, 4x100w solar panels and 2x100ah lithium batteries. The main goal of this upgrade is to always keep the refrigerator on during trips, including while driving down the road.

I didn’t want to replace the original Marvel-brand 120v a/c compressor refrigerator, because new ones don’t have that puffy rounded-corner 1950’s look, and also because it still seems to work like new at 65 years of age.

So far I’ve done everything except to mount the new solar panels on the roof. (I’m still making mounting brackets from stuff I bought at Home Depot.) Everything else is up and running, so last week I started experimenting by temporarily placing 2 of the 100w solar panels on sawhorses, wiring them to the new solar controller, disconnecting city power, and turning on the old fridge, now wired to the new inverter.

By dawn each morning, the new battery monitor shows about 13.25 volts and about 94 percent remaining power. Within three hours the batteries are back up to 100 percent, even before the panels get direct sunlight, with only half the panels on line so far.

While doing this experiment, the trailer’s doors, windows, and vents have been kept closed. The trailer’s inside temperature climbs above 100 degrees each day under the hot sun. The old fridge stays icy cold all the time. The new inverter doesn’t seem stressed either, because its built-in heat-triggered cooling fans haven’t been running.

I assume a new 12v d/c compressor refrigerator like you are considering will use less energy running directly from the batteries than my 65-year-old 120v a/c fridge running via an inverter. In other words, you shouldn't stress about running out of power.

[mrdes8]

I installed a Dometic CRX 110 in our '68 Overlander remodel. About 3.9cu ft, works well for us for about 5 days. Went this size to fit under a 36" counter, also no exterior vents (holes). We have 400 watts solar and 250 ahr AGM, works well here in the SW. When we do plugin (sometimes for months) we continue to run through the 12v side.
Good luck, Mark D