AC/DC Compressor Refrigerators

[Community Alumni]

I was looking at a motorhome that was equipped with an all-electric compressor refrigerator. I have never seen one before in a motorhome.

I found a video on the net about the pros and cons of compressor v. absorption units and some of the pros on the compressor units is the ability to regulate the temperature much better and the fridge does not need to be leveled. One of the negatives is the sound they make when the compressor comes on, just like the residential units.

It's worth mentioning the RV came equipped with 200 watts of solar panels to help keep the batteries charged. As someone that dry camps frequently, I'm wondering how often the generator has to run to keep the batteries charged. As you all know, absorption refrigerators can run practically forever on very little propane.

I'd like to hear from anyone that has one of these RV compressor refrigerators, not the residential ones.

The link below shows the refrigerator I saw in the motorhome. There is next to nothing on the net about these fridges so I'm assuming they're fairly new.

https://www.rvpartscountry.com/Norcold-AC-DC-RV-Refrigerator-DE006-1r-built-in.html

[theoldwizard1]

Dusty R wrote:
Have any of you campers with solar panels camped in Michigan and noticed less power being produced?

Most people camp in MI during the summer months and there are more hours of sun from May through September than any other time if the year.

Of course, many campsites in MI are under trees !

Add more solar panels and don't park under the trees !!

[theoldwizard1]

Ivylog wrote:
My EnergyStar Whirlpool 21 cuft draws 9 amps DC measure before the inverter...96 Watts. Its duty cycle is 40-45% confirmed with a KW meter...1.2-1.3 KW/day. 3X the size on 50% more power and half the price of DC powered units. Not a hard decision.

Very impressive numbers ! Clearly a great refrigerator for a large family !

[wa8yxm]

Dusty R wrote:

Have any of you campers with solar panels camped in Michigan and noticed less power being produced?

Dusty

Do not have solar but Detroit Energery does. the Lapeer Solar Farm (It has a different name but you can google on that one and find it)

Big field of solar panels on the North side of I-69 east of Lapeer. I pass it often in the summer.

[MrWizard]

lookup Sunfrost refrigerators and/or solar off-grid fridge

[Dusty_R]

During the first energy crunch I took class, at a local community collage, on alternate source of energy. There is was said that Michigan ranked 47th out of the 48 continual states of available sunshine.
Have any of you campers with solar panels camped in Michigan and noticed less power being produced?

Dusty

[Ivylog]

My EnergyStar Whirlpool 21 cuft draws 9 amps DC measure before the inverter...96 Watts. Its duty cycle is 40-45% confirmed with a KW meter...1.2-1.3 KW/day. 3X the size on 50% more power and half the price of DC powered units. Not a hard decision.

[jplante4]

gemsworld wrote:

jplante4 wrote:
We have the new Dometic AC/DC compressor in the store. When we first got it we hooked it up to a group 27 12v battery and it ran for 40 hours before the battery got down to 10.7 volts. Then we plugged it in and watched the temp. It stayed constant until the whole thing stopped working in 2 months time.

Are you saying the fridge stopped working as in it failed after being used for only two months? If so, what was the cause of the failure?

Yes it failed. I believe it was one of the first ones produced for Dometic and may have been a floor model. See my comment in the Prevost vs. Newmar post in class A forum about the quality of newer appliances.

We just got the replacement and have not sent the failed unit back yet, so I don't now the cause.

[bob_nestor]

When I looked into this a couple of years ago the most efficient (in terms of power consumption) were the EvaKool units built by an Australian company for RVs (Caravans) used in the Outback. Unfortunately I couldn't find any way of getting one imported into the US.

EvaKool

I do a lot of dry camping and opted for a portable Engle 12/1220v refer/freezer that seems to have the lowest power consumption for portables. Even so, with my 300w of solar and two 12v Lithium Ion 125ah batteries I can only go about 3-4 days before having to top off the batteries with the generator.

[crosscheck]

From 2011 to 2016, we had a NovaKool 7500 fridge/freezer AC/DC unit in our TC. 95% of our camping was dry. Had a generator and used it maybe three times. Our RV electrical usage was moderate, had 330W solar and 4 6V AGM batteries. Pros and Cons as followed:

Pros:
1) Can be out of level for indefinate amounts of time which suited our camping style(boondocking)
2)Used 1/3 less energy( not electricity), than absorption fridge which unless you are trying to save the world, not a big issue.
3) Outside measurements for a Compressor unit is 1/3 less for the same interior volume as an absorption unit. A 9cuft NovaKool will fit in the same spot as Our pressent 6 cuft Norcold propane fridge.
4) Freezer has frost forming on walls 20 minutes after start up.
5) More consistant inside temperatures especially in hotter weather.
6) Never heard of a compressor unit catching fire and there must be many 100,000,000 of units throughout the world.
7) Many of the places we camp in northern BC, do not have available propane fill ups and as we use propane for cooking, hot water, heat, BBQ, you do not want to run out of propane.
😎 Our unit pulled 4.4A when cycling as per amp meter.(60W)

Cons:
1) You can hear the compressor(quiet), while the absorbsion units are dead quiet.
2) 200W of solar and 2 batteries minimum alone for the fridge is required.

We are satisfied with the 6cuft Norcold in our TT, but if it ever failed, I would replace it with a 9cuft NovaKool as we already have 490W solar and 4 6V GC2's.

Dave

[BoonHauler]

3 tons wrote:

mobeewan wrote:
I've been looking at Novakool. They make Marine refridgerators and freezers that can run on 12v or 24v. One similar in size to the Norcold is only a couple hundred dollars or so more expensive, but they are proven units used in boats. I've seen a couple YouTube videos were people built their own campervans from scratch and installed Novakool units. They also had solar panels installed on the roofs with about 400 to 600 watts of battery.

Since I plan on using solar in the future and building a camper van or enclosed 16 foot utility trailer/camper with 800 to 1000 watts of solar I'll probably go one of 2 routes. One is a large Domestic chest refridgerators/freezer in freezer only mode and a dorm fridge. The other route is a tall Novakool with freezer on the bottom and if needed a small dometic chest freezer/fridge I can fire up if I needed a little extra freezer space.

If I stick with just my 28 ft TT I am considering adding solar any way. I might also replace my weak Norcold with a Novakool.

For the Novakool RFU 6800 they list the amps at 5.2 @12v, so a sufficient of solar to augment makes perfect sense.

I have a Nova Kool 6 cuft refrigerator and 6 cuft freezer and love them! .... they work great! Way better than absorption units!

A 50% duty cycle is a good number to use as prichardson mentioned.

I dry-camp 100% of the time, a properly sized solar system is the only way to roll ..... 😃

[theoldwizard1]

CA Traveler wrote:
The AC power is 108W, 12V is 42W and 24V is 53W. This suggests that the AC power is rather inefficient, but when plugged in most would not care.

Concur !

As mentioned previously, most of these use a Danfoss compressor (the company has been bought and sold a couple of times in the past 10 or so years so I don't know if that brand name is still used) and when running on AC actually use a converter to generate the 12/24VDC (which is more interesting as the DC is actually converted to a variable frequency 3 phase AC current !) This suggests that maybe you should a better 12VDC converter (power supply).

If I boondocked a lot, I would have an invert/charger/transfer switch and I would just leave the refrigerator connected to DC power, via an appropriate fuse.

[theoldwizard1]

prichardson wrote:
About the only real advantage of a compressor type refrigerator in the RV world is that it has a quicker recovery time.

Compressor based refrigeration provides a much more consistent internal temperature over a wide range of ambient temperatures.

[CA_Traveler]

The amps in the posted link are rather limited and inconsistent. What is needed for a RV that is off grid is the power usage as in Ah or KWh. ie 0.9A AC for how long or say average KWh per day or year. That information is available for popular residential refers.

The AC power is 108W, 12V is 42W and 24V is 53W. This suggests that the AC power is rather inefficient, but when plugged in most would not care.

42W is reasonable but for how many hours a day is the critical missing information?

This unit may be efficient and a viable option for it's size but the information to determine this is lacking.

With 220Ah batteries at 12V the refer would run for 31 hours before reaching 50% SOC. If the cycle time is 25% then it's good for 5+ days. ie For fully charged batteries and no other loads.

Amps: 0.9 at 120V AC; 3.5 @ 12V DC; 2.2 @ 24V DC.

[Lwiddis]

Regular use of a generator when you have a solar system is a “fail” for your solar system.

[prichardson]

About the only real advantage of a compressor type refrigerator in the RV world is that it has a quicker recovery time. From my experience in the marine world; when operating on 12VDC these units draw 5 to 7 amps when running and a duty cycle of about 50% (ie will be running 12 out of 24 hours).