Running a Dometic fridge on 12V

kivelakl · 07-13-2019, 11:01 PM

Hi - My fridge is supposed to switch automatically from 12V to 110. It runs fine when the inverter is on but doesn't come on otherwise. Can't figure out what I'm doing wrong. This is my first RV and I have a lot to learn. Thanks!

hbn7hj · 07-13-2019, 11:42 PM

There are very few fridges that switch from 12 volt to 110 and back automatically. I once said there were none but was wrong. Give us your model number to be sure.

Those I have seen that do that were originally designed for sailboats, and are not available aftermarket in the US. Leisure Travel vans installed the one I saw. I believe they switch from solar to propane to AC depending on what is available.

Didn't realize it is probably a compressor fridge in a Hymer Activ. Those that know about compressor fridges will need to answer.

kivelakl · 07-14-2019, 01:56 AM

You're right - it's installed in a 2018 Hymer Aktiv. After thinking about it more I suspect it's a power mgmt issue and I may not have initialized the batteries correctly before setting out. Any other ideas, please advise. Thanks!

MsNomer · 07-14-2019, 05:10 PM

Engel switches automatically.

mumkin · 07-14-2019, 05:44 PM

I had this same fridge in my 170. The first thing a tech told me was to go to the circuit board and shut off the 110 fridge breaker ... and to never use 110 for this fridge. It works best on 12v... more efficient. It uses very little power on 12v, unlike the old 3 system fridges. I haven't used 110v for a fridge for over 4 years now.

Keep it on 12v all the time and you will never again have to worry about the unnecessary switching back and forth.

Problem fixed...

kivelakl · 07-14-2019, 05:53 PM

Thank you for the suggestion.

blackbourn3704 · 07-14-2019, 07:24 PM

For what it's worth, this is from a Dometic user's manual : "1. DC MODE
DM2663 When operating in DC mode (3-way models only), the DC mode indicator lamp is illuminated and all other lamps are off. To select another op¬erating mode, turn off the DC mode by pressing the DC selector button. The DC lamp is turned off. When there is no charging of the house battery, switch to AUTO mode or GAS mode, since run¬ning the refrigerator on 12 VDC will quickly drain the battery."
You can download Dometic manuals from this site:
https://www.dometic.com/en-us/us/pro...gerators?at=rv
Scroll down to find your model, then click on the picture. It will take you to something like this picture. Click on "Manuals" at the bottom of the screen then select the manual you want to download.

mumkin · 07-15-2019, 01:49 PM

It is NOT a 3 system fridge. There is only one switch... on/off. It is a 12v fridge that will work on 110, but you never need to actually let it switch to 110...

blackbourn3704 · 07-15-2019, 03:21 PM

I have no idea what model is being addressed. Just know they are not all the same. Tried to help by posting a link to the manufactures manuals. I'll shut up and go back to my corner.

bigfelipe · 07-15-2019, 09:02 PM

How long can you run one of these new 12v comp fridges on battery? Are they viable for boondockers or is the tech not there yet?

avanti · 07-15-2019, 09:39 PM

Quote:

Originally Posted by bigfelipe

How long can you run one of these new 12v comp fridges on battery? Are they viable for boondockers or is the tech not there yet?

My NovaKool 6800 (a large fridge/freezer) consumes around 6.7 amps when running--by actual measurement. So, at a 50% duty cycle, a single 110Ah taken down to 50% would get you maybe 16 hours, assuming no solar and no engine recharging. I have four such batteries, modest solar, and a second-engine alternator. With this setup, the fridge is a modest part of my power budget. Driving for a short distance every day replace the consumed power.

booster · 07-15-2019, 10:18 PM

Quote:

Originally Posted by bigfelipe

How long can you run one of these new 12v comp fridges on battery? Are they viable for boondockers or is the tech not there yet?

Our Isotherm is smaller than Avanti's at 3.1cf, which about what the normal class b 3way size has traditionally been, and uses about 3.2 amps running with commonly 18-40ah per day use depending on temp. Typical temps in the 80's usually are in the 25-30ah range. We have the same size battery bank as Avanti, so can run a long time without charging as we would rarely use over 50ah per day total. If we have good sun conditions, we will have full batteries every day without shore power or driving, from the 300 watts of solar.

So, yes, the technology is ready for prime time but with the caveat that you provide more power than the 3 ways use. That is getting quite easy to do these days.

GeorgeRa · 07-15-2019, 11:16 PM

My experience is exactly the same as Booster's except I only have 230Ah AGMs.

mumkin · 07-16-2019, 03:14 PM

I have a larger fridge than the one in the Aktiv. Mine is 5 cf. I have 270w of solar and 2 group 31s (about 210-220 ah). I can go indefinitely running the fridge, fantastic fan, lights, and time to charge up the electronics once a day with the inverter. This is assuming that you have sun for part of the day at least. If needed, the UHG will finish the topping up with a short drive or some idling.

I would say that the fridge technology is vastly improved. While propane could run my fridge to the limit of that tank, when it was hot, it didn't do a very good job of keeping things cold. These 12v compressor fridges cool very quickly and maintain the temp very well. No more having to turn on the fridge the night before... I turn it on when I start packing the rig in the morning. My last load will be for the fridge and it is nice and cold in there.

cruising7388 · 07-16-2019, 09:57 PM

Quote:

Originally Posted by blackbourn3704

I have no idea what model is being addressed. Just know they are not all the same. Tried to help by posting a link to the manufactures manuals. I'll shut up and go back to my corner.

No need to go to your corner. Hey, "experts" are only a page or two ahead of ya.

The three way absorption systems you refer to are gradually being displaced by high efficiency compressor units that provide improved temperature regulation and are more tolerant of off level operation. The first generation of the compressor units operated on both 12V and 120V but the Norcold compressor fridge in our 2017 210 Popular runs on 12V only.

bm196 · 07-21-2019, 05:38 PM

I have a Norcold DE0051 in my van. It is only AC or DC. It switches automatically when turned on and you change power mode. There is no manual switch to go from AC to DC.

lightspeed · 07-21-2019, 05:42 PM

i am curious which domestic fridge is being talked about . as i didn't see what model other then the name "domestic " is it this fridge ?? https://www.amazon.com/Dometic-CRX-6...ateway&sr=8-11

i see where one person mentioned on the amazon website .

FYI, I measured the current (12v) at about 4 amps when the compressor and fan were running.

is this a good low current , is there anything similar to this refrigerator that draws lower current from car batteries?

thanks in advance .

avanti · 07-21-2019, 06:02 PM

Quote:

Originally Posted by bm196

I have a Norcold DE0051 in my van. It is only AC or DC. It switches automatically when turned on and you change power mode. There is no manual switch to go from AC to DC.

For anyone trying to follow this discussion, it is important to keep track of which products are compressor units and which are absorption. The voltage issues are entirely different between the two.

The Norcold DE0051 is a compressor unit. Like most, it uses the venerable Danfoss inverter. The electronics necessary to operate these compressors are native 12VDC. "Multi-voltage" fridges such as the DE0051 simply have fancy power bricks capable of converting a variety of voltages to 12VDC. They will always be most efficient at 12VDC.

Absorption fridges (which will always accept propane) are different. They have one or more electric heating elements that take the place of the propane flame when running from electricity. These elements may be native 120VAC, or 12VDC, or both. Which mode is most efficient depends entirely on the details of the particular unit.

elgee · 07-21-2019, 06:38 PM

2009 RT220P
After plugging into shore power, we have to manually switch our fridg manually. Automatic never works. So,not a problem.

stevegoldfield · 07-21-2019, 07:14 PM

I can get 3 or 4 days boondocking on my refrigerator in my Banff with two 100W solar panels, two Lithium iron batteries and an AGM. After that, I have to run the underhood generator for a few minutes to bring the batteries up above the minimum. The power usually goes off at night, but it's cooler then so I have not had any food spoil.

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