A very different all-electric refrigerator

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By Greg Illes
The vast majority of RVs are equipped with the familiar dc/propane fridge, also sometimes called a “recombinant gas” fridge. It’s an archaic design, sensitive to poor leveling, occasionally prone to catching fire, and amazingly poor at holding inside temperature constant. It’s also so inefficient that it can take almost a full day to cool down after being shut off for a while, or being loaded up with warmish groceries.

So why are these pitiful appliances so ubiquitous and still sold in droves by the likes of Norcold and Dometic? Well, they kinda work and they’re kinda cheap. They use very little electrical power and darn little propane. And people put up with them.

Not me though. I was so disgusted with my propane fridge performance that I put a brand-new after-market cooling unit in it a few years ago. I saw absolutely no improvement (although the heavier gauge metal is probably less likely to crack and leak or cause a fire), causing me to get even more disgusted.

So I started researching all-electric fridges, such as those installed in high-end “park” model RVs. These are essentially relocated residential fridges, and when I looked up their power consumption I about had an aneurysm. Are you ready for this? A typical 120V fridge will chew up nearly 200 watts of power when running, and burn through almost 2000 watt-hours in a day.


For a plugged-in RV, this is no big deal. But for us 12V-only boondocking types, that means that the fridge would drain a 300-amp-hour battery pack every day. Even worse with the losses from having to provide that 120V through an inverter.

Even with my 400W solar array and 360AH (usable) lithium battery pack, it was an impossible scenario. I’d have to be running a generator for hours every day, just because of that power-hog fridge. Some folks may not mind living on top of a running engine, but it’s not for me. I needed a way to have my solar/battery combination and my fridge be compatible.

For a while, I abandoned the search, but I later learned about a technology that’s common in the marine/boating world, but not that familiar with RVers: the 12V Danfoss compressor.

Danfoss is a Danish company that began in 1933. You can look them up and get a lot more info, but suffice it to say that they seem to own the market in 12V refrigerator compressors. Virtually every maker out there – Vitrifrigo, Novakool, others – use the Danfoss subsystem. The motivation is simple: reliability, efficiency, low power consumption.

As I looked deeper into these products, more advantages came to light. The Novakool unit that I ended up purchasing took up the exact same space as my old Norcold. But, where the Norcold provided six cubic feet of capacity, the Novakool had nine cubic feet. The reason is that the 12V compressor and cooling coils take up far less space than the bulky chemical engine of the propane fridge. In addition, all the hardware is lighter, and I even ended up shaving more than 20 pounds off my slightly-chubby motorhome.

When I told my wife we’d be upgrading the refrigerator, she pushed back. It’s working fine, she said; we don’t need to spend the money, she said. I told her it would have 50% more space. When will it get here, she said. Project approved.

The first time I switched it on, instead of 8-12 hours of cool-down time, the whole fridge and freezer were at temperature in 45 minutes. It was impressive.

The most important thing – the power draw? Specifications say the compressor draws 5.3A on the 12V line when running. I measured it at … 5.3A. So then I let the fridge sit for a day, and measured how much power it drew. The weather and coach interior were around 75-80 F, a pretty good mid-range test. Fridge set to 40 F, freezer to 0 F. Total power draw for about 24 hours was just under 20 amp-hours. In other words, the compressor ran for only about one hour out of every six. Even if warm weather causes that to double, I’m still good with it.

I should note that I did take some extra time and added foam insulation anywhere I could during the installation. These fridges don’t require any external venting like a propane fridge does, so I sealed up those vents and insulated them as well.

Not everyone will benefit from this upgrade. It’s expensive ($1200 and up), and you really need a good solar/battery system even with its modest power draw. But for veteran boondockers, it can be a real – uh – boon.

Bottom line? So far, so good. I don’t have a lot of time on it yet, so I won’t give it a reliability score for a year or two. But all the potential pluses are real, and I’m – what’s the phrase? – a happy camper.

Greg Illes is a retired systems engineer who loves thinking up RV upgrades and modifications. When he’s not working on his motorhome, he’s traveling in it. You can follow his excellent blog at www.divver-city.com/blog


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Ron Painter
Ron Painter

I was looking at new travel trailers in Burlington WI yesterday and was amazed to see that just about every Gulfstream rig had the 12vdc fridge. About time!! On the other hand, I do have to (carefully) boast of my existing Dometic Fridge / Freezer that continues to work just fine. What is so amazing is that it is in a 1991 Class C Fleetwood Tioga! Just darn lucky I know! I had to replace the ignitor board about 4 years ago with a Dinosaur Electronics board for $85. How long can mine last?? If I end up with the… Read more »

jane shure
jane shure

The best thing you can do with a gas refrigerator is to take it out to the gun range and shoot it full of holes. I switched over to an electric years ago and I have been very happy. I did install 2000 watts of solar and I did the work myself for a big savings to myself. The only problem is if there is several days of very dark skies and tall trees. I next plan to go to lithium batteries and hopefully solve that problem.. If you are where there is plenty of sun shine you will not… Read more »

Tommy Molnar
Tommy Molnar

19KC69 says “However, most people will fall over backwards when they find out what a good solar system will cost”. Ya got THAT right pal . . .! But, if you can afford it, you’ll never again be without it.

David Crymes
David Crymes

I would love to know if he has hard ice cream with this new refrigerator. I have been searching for a late model diesel pusher and hoping for a residential refer and feed up with our side by side propane that give me ice cream that won’t harden. Our domestic is located in a slide and even with additional fans, we can’t get hard ice cream. We turn the settings up to accomplish the feat then all the produce in the refer freezes. I had no idea that residential refers used that much electricity.

rag-ftw
rag-ftw

Does anyone know of a DC refrigerator/freezer that is 12 cu ft or larger?
Looking to replace my No-Cold 1200!

Gary
Gary

Imagine what they could do in the space of a Norcold 1200…

Bill Jeffrey
Bill Jeffrey

Fifteen years ago, I bought a 43-quart chest refrig-freezer from Engel, one of the first with a Danfoss compressor. It has been a great unit – not a single problem in all those years. For the first five years, we used it in our trailer, while making trips of three or four weeks at a time. About 10 years ago, we began using it as a full-time freezer in our home. In other words, it has run 24×7 for over ten years without a hiccup. Talk about reliability! The unit will operate from 120VAC or 12VDC, and comes with power… Read more »

Betty
Betty

You say this needs a solar array. But what about using it with a converter? Wouldn’t that let it work on shore power?

alvin.e
alvin.e

When your shore power is plugged in, the battery is automatically charged and therefore also automatically provides the 12V for refrigerator – problem solved.

Drew
Drew

Greg,

How much was yours?

Bill
Bill

My father-in-law used these for years in 3 of his Class B motorhomes and one class C over a period of 30 years No problems, except for sending it back for a compressor change maybe twice. He special ordered his RVs and specified the 12 volt electric refrigerators, with little or no upcharge. The one Class B he bought off the lot that had a propane refrigerator was a constant problem. We’ve had 6 Class Bs and three Class As most with propane refrigerators, with not a lot of problems but I think we have had to replace two and… Read more »

Robbie
Robbie

Greg,
We’re full time boondockers and use a residential fridge, but we paid $$$ for our solar system. I am intrigued by the Danfoss compressor. Thank you for a great resource and an article with perfect explanations.

Harry
Harry

Tell us the size of refer you installed, if 20cf, 20 ah is impressive, if 3cf not so good!
A 10.7 cf residential will run 1/2 hour every hour and use about 80 ah per day. Surprised Novacool runs only 1 hour out of 6, that is efficient.
A 10 cf Nocold will run about $2300 installed, so Novacold at $1200 is cheap!

Alpenliter
Alpenliter

“But, where the Norcold provided six cubic feet of capacity, the Novakool had nine cubic feet.”

George B. Sears
George B. Sears

The 6 cubic foot Dometic I had in a TT had a 2000 BTU burner. I think that is 600 watts, and that’s about what the electric heater drew. The cycle was at least 50%, so 600 watts x 12 hours a day. Yikes. This Dometic drew about .7 amps all the time and 1.3 when the fan kicked in. Overall, about 30 amp hours a day. This is not for any cooling. This is for a board and a gasket heater. I don’t have the TT anymore. I have a van fridge with a Danfoss. We live in a… Read more »

John Whitney
John Whitney

I look forward to updates. Especially how well you can place items in the unit in comparison to your previous unit.

19KC69
19KC69

We have a 1400W solar system (4 house panels) with 320 usable amp hour lithium batteries. We purchased a 10.7 cu ft residential fridge (retailed at $550) and are very happy with the results. It doesn’t even show 1 amp on the AC output load on the inverter remote. We are fulltime RVers and avid Boondockers. I think the key is to have a sufficient amount of solar to meet your needs. We decided to invest more on our solar system so we wouldn’t have to skimp on power usage. However, most people will fall over backwards when they find… Read more »