12VDC Fridge

[Chester Taje]

I am interested by what people think about a only 12vdc fridge.I personally prefere propane with the option of 3 way 110 -- 12volt--or propane.

How long would a good battery last etc.
Thanks
Chester

[Pete Dumbleton]

If you mean an RV fridge, the 12VDC option is the weakest, then comes the 120VAC and finally the LP is the strongest -- Unless you have some serious battery recharging resources, you won't get to run it long -- Tales abound of folks leaving the fridge on 12VDC on a weekend and depleting both the trailer and tow vehicle batteries.

[Chester Taje]

Thanks Pete--Thats what i figured also.Reason I asked is that some new units are coming out with only 12VDC and no options.This did not make sence to me.

[Gina D.]

12v is OK for keeping it going while towing. I ran a batterry down in just a few hours using a 12v coleman fridge once. And that was whimpy compared to the draw on standard fridges.

If you have to go only one way, go propane.

[Frederick L. Simson]

Reason I asked is that some new units are coming out with only 12VDC and no options.

Supposedly, these new 12 volt DC only fridges are a compressor type, and are supposed to run differently than the standard absorption type RV fridge we all know & love.

[Chester Taje]

Supposedly, these new 12 volt DC only fridges are a compressor type, and are supposed to run differently than the standard absorption type RV fridge we all know & love.

Maybe question should be---How do the compressor type work.Are they efficient and easy on battery.

[Byron Kinnaman]

Maybe question should be---How do the compressor type work.Are they efficient and easy on battery.

I found a Norcold DC0040 that is a 12volt compressor type. The current draw is 2.7 amps. When I checked their web site for specifications there is no mention of what would be expected for on and off times. I looked at the manual and didn't see enough to know what the average current draw would be. I was hoping to find something like an ambient air temperature vs average current chart. Maybe a phone call to Norcold could answer the questions.

[Brian B-P]

There are at least three technologies for refrigeration with 12VDC power...

Absorption is the usual RV 'fridge: it just needs a bunch of heat to run, and low-voltage electricity is the least effective way to do that (burning propane is generally the most practical). I think that it makes no sense to choose this type if it is to be run only on 12VDC.

Compressor-type units work just like the typical home 'fridge. Bryon gave an example, but in earlier topics there were reports of more experience with them. Judging from reports of their use worldwide, in battery-operated applications, it appears that this is the most efficient and effective electrically-powered choice, and units optimized for operation from 12VDC are significantly better than running an AC unit via an inverter.

Solid-state coolers run from 12VDC, and are inherently simple, but don't seem to be nearly as efficient. I have two of these, and find that they cannot maintain enough temperature differential to be effective in warm weather, and can run a car battery dead in a few hours.

See 2 way Refrig for an example of an earlier round of this topic.

[brendadave]

I am interested by what people think about a only 12vdc fridge.I personally prefere propane with the option of 3 way 110 -- 12volt--or propane.

How long would a good battery last etc.
Thanks
Chester

I went and looked at a 2006 Trillium that someone had for sale, and I asked them about the fridge as I was sceptical as well.

They had used it on battery for just over a week and it had worked great for them, even the freezer part was still making ice for them, they showed me that in their demo. They were not sure how long it would have lasted as they only used it once.

When I talked to the Trillium Trailer guys, Joe told me that it should run about 7 - 10 days on the 12volt without recharging the batteries (2 - 6 volt).

[Chester Taje]

I went and looked at a 2006 Trillium that someone had for sale, and I asked them about the fridge as I was sceptical as well.

They had used it on battery for just over a week and it had worked great for them, even the freezer part was still making ice for them, they showed me that in their demo. They were not sure how long it would have lasted as they only used it once.

When I talked to the Trillium Trailer guys, Joe told me that it should run about 7 - 10 days on the 12volt without recharging the batteries (2 - 6 volt).

That info is what I was looking for.Maybe the 12vdc systems have really improved over the last little while.

[DAVID K]

The 12v compressor types leave a lot to be desired. I have one in my boat, works great, but is very noisey in a confined area.

[Chester Taje]

More good info.Noisey to operate in confined space.Thanks

[Pete Dumbleton]

Brian, good summary of what's available -- I have gotten the impression that the 12VDC compressor models have gotten efficient in recent years.

Of course, any heating or cooling arrangement is going to depend heavily on the temperature differential and the insulation -- With small, front door fridges, an added problem is that when the door is opened, all the cold air flows out and is replaced by warmer air, so even the interval and duration of access must be considered.

At minimum, in an RV situation, an interior circulation fan and a thermostatic exterior fan for the cooling stack or heat exchanger are desired efficiency devices.

[Brian B-P]

Good point about opening the door on the small refrigerators, Pete. I have noticed that many of the imported compressor-type 12VDC coolers are configured in a chest style: horizontal, with the door on the top, like an ordinary insulated cooler. This suits their use as portable camping units (rather than built into an RV), and minimizes cold air loss when opened. If there were space for this in a travel trailer, I think it would help performance there, but it's hard to imagine where this would go in most layouts.

[Byron Kinnaman]

I've been in boats that use the chest type fridge. The one I remember it was built into the galley counter. You had to move stuff off the lid to get in and when the lid was closed there was galley counter space.

Don't know how you would manage that our trailers.

[colin k]

When I talked to the Trillium Trailer guys, Joe told me that it should run about 7 - 10 days on the 12volt without recharging the batteries (2 - 6 volt).

Hmmm. I doubt that very much. Too many variables for one thing. How hot outside. Whats in the fridge. How often is fridge opened?

I have a 12v compressor fridge (norcold)in my boler. I run 2 deep cycle 12v batteries (each 110 AH)and a 70 watt solar array. I also wired a computer fan to blow over the coils when the fridge comes on. The batteries can keep up with the solar array but without the array i would say probably a few days both batteries would be very low depending on how hot it is outside.. Biggest grip with the 12 v compressor fridge is the noise. When it comes on it vibrates the boler so ear plugs dont work. This spring im going to modify the fridge and isolate the compressor motor with softer rubber or hang the compressor on rubber mounts. Other than that the fridge works pretty good.