New refrigerator 110 or 120V?

[Chlyman]

I am looking at buying a new refrigerator for my trailer. Why the difference between 110v and 120v? I have not wired the trailer for this yet. Is the difference based on the wiring in the trailer? It can't be the shore power can it? Help!
Thanks,
Carolyn

[clancy_boy]

Your common household voltage is 120V. Some people commonly call it 110V, but they are the same for what you are asking for. Now, did you mean to type 220V in your question? That would be a difference and a mistake you would not want to make - your trailer does not have 220V (really 240V).

Confusing? It can be. You are fine with a 120V fridge. Remember, if you go off grid then you will need a duel power electric/gas unit to keep it going - batteries will not do it for power to a fridge.

[DKB_SATX]

As clancy boy said, common household power in North America is 120V, but that's a nominal voltage. It generally varies a bit based on a number of factors, at the moment my UPS says it's 121V at the outlet, for example. Usually as long as it's above about 108V and below about 130V everything will work fine. "Shore power" should be the same as household power but on a 30 amp circuit.

Are you looking at RV fridges? (ones that can run off of either electricity or LP gas.) Dometic, the biggest manufacturer of these, refers to their 2-way refrigerators as "110V AC/LP Gas" on their website, and most vendors use the manufacturer's description so that's likely where the confusion started.

The other option, just in case you want more choices, is a refrigerator that uses a Danfoss 12V DC compressor. This would be better for a trailer with plenty of solar or for someone who rarely boondocks for more than a day or two, since it'll only work with electricity, but it'll work well off batteries as long as there's enough battery capacity.

[Chlyman]

I guess the confusion is that on the Dometic web site, for example, it lists 2 models, one is 110v ac/LP and one is 120v ac/LP. That is why I wasn't sure which one to get. So are they basically the same, and labeled that way to avoid confusion?
Thanks again!!!

[clancy_boy]

They are the same - normal household current of 120V.

[Chlyman]

Thanks for everyone's help!

[bryanl]

re: "a refrigerator that uses a Danfoss 12V DC compressor." -- things have changed in the last ten or twenty years. A good EnergyStar rated refrigerator is much less expensive than either a Danfoss based one or the typical RV absorption type and the efficiency is getting practical for RV use.

A 5 cf GE fridge at Walmart was under $200. You could add a 200 watt solar system and an extra battery or two to run it for a total outlay of less than the cost of a new RV fridge.

[DKB_SATX]

Originally Posted by bryanl

re: "a refrigerator that uses a Danfoss 12V DC compressor." -- things have changed in the last ten or twenty years. A good EnergyStar rated refrigerator is much less expensive than either a Danfoss based one or the typical RV absorption type and the efficiency is getting practical for RV use.

A 5 cf GE fridge at Walmart was under $200. You could add a 200 watt solar system and an extra battery or two to run it for a total outlay of less than the cost of a new RV fridge.

There's nothing on GE's site about the current draw of these refrigerators. Even assuming that it's as efficient as the Danfoss-equipped ones, you'll have losses from an inverter to produced 120v current for it, and it's not designed to be installed in a moving vehicle. I guess it would only have to last 1/6th as long as an RV/yacht unit to make up for that, but my 36-year-old Dometic is still working on electric and (when parked) on gas. I need to figure out why it won't stay lit on the road. So, it would need to stand up to 6 years of travel to break even on that front.

[Chlyman]

Isn't driving with a running propane appliance a big hazard?

Carolyn

[TouringDan]

Chlyman

It is kind of like flying I guess. It is only hazardous if you crash. We drive with our refer operating all the time, just as we drive our truck with 20 gal of gas about 4 ft behind us.

Now I am confused by the Dometic web site. Why would they list two separate voltages: 110v ac and 120 ac?

Dan

[DKB_SATX]

Originally Posted by Chlyman

Isn't driving with a running propane appliance a big hazard?

Carolyn

As with many things, there are two camps on that one. I think that driving with a running propane appliance that's designed to function properly in a moving vehicle is just fine. It is important to maintain the fridge properly, but generally the problem is that you can't get the gas valve to open, not that it doesn't shut it off if the pilot blows out. Modern ones relight themselves relight themselves unless they're broken.

If you live in Texas and travel in the summer, a working refrigerator on the road is a wonderful thing.

[TBRich]

Originally Posted by Chlyman

Isn't driving with a running propane appliance a big hazard?

Carolyn

We always travel with the fridge running on LP. It's designed to do that safely. It may be a different answer with older models (ours is an 06). There are those who don't travel with LP and there are many who do. In our climate, it's a must, and we have never had a problem.

[bryanl]

re: "There's nothing on GE's site about the current draw of these refrigerators." -- I don't know what it is but I sure seem to stimulate these knee jerk responses.

First item: current draw isn't the issue, energy use is. EnergyStar appliances have tags that identify estimated cost and energy use averages. Both by tag and by direct measure (there are discussions around), average energy use is can be under 1 kWh per day for these appliances, even for large refrigerators.

The government website has a spreadsheet with EnergyStar appliance data as well.

As for inverter loss and such things, they are a factor but not one that amounts to a significant concern. Inverter loss is about 10%. Battery cycle loss is about 20%. Wiring loss is about 5%. Opening the door frequently is 30% or more. And on it goes.

Look around. Larger RV's often offer household refrigerators OEM. There is a lot of discussion of the pros and cons on both RV sites and on 'alternative energy' forums. A number of RVers have replaced absorption refrigerators with household ones and report satisfactory results.

What suits you may be different but that doesn't negate what others have found.

re: "It is only hazardous if you crash." -- usually not as modern propane systems have automatic shutoffs and other safeties for such events. The risk is that of an open flame or an appliance igniter at a fuel stop.

[DKB_SATX]

Not to be argumentative, but my "knee-jerk response" on the power needs of the sort of fridge you mentioned was to go looking for information provided by the manufacturer to see what might be required to operate it from battery power, and I found that GE doesn't offer information about its power needs on their site. Current draw is a component of energy use and a common specification of electrical appliances, I hardly think it was an unreasonable data point to look for. On GE's page for the refrigerator in that size range from Wal-Mart's site they didn't offer any such information in the text of the specifications... I didn't notice it yesterday because you have to click on a small image to get the energy guide.

So at about 1 kWh/day you'd want an extra battery more or less dedicated to supplying the refrigerator and enough solar array to recharge that battery plus batteries for your other needs on an average day.

As to negating anything, re-reading what I wrote I don't see anything that says it can't be done, it says that there will be certain things to deal with such as needing an inverter in the first place, dealing with its losses and the potential for installation in a trailer to be hard on the mechanism. I also pointed out that the cost advantage of a 120V compressor fridge would mean it only needs to last about 1/6th as long, which is hardly a negation of its viability.

[bryanl]

re: "I found that GE doesn't offer information about its power needs on their site. Current draw is a component of energy use and a common specification of electrical appliances,"

no spoon feeding on a silver platter, I'm afraid.

Household appliances aren't usually sold to, or marketed for, the RV market.

When it comes to appliances, the usual ratings are in watts. Current is only typical in low voltage DC stuff. One of the major sources of 'difficulties' I see in RV energy needs planning is due to using inconvenient units.

Yes, a complete system can involve a lot of issues. The point though, was that you can buy that complete system at less or equivalent cost than the usual fare. That puts a strain on considering the options as they aren't so clear anymore.

[Jim in Pima]

I just replaced the electric heater in my RM100 fridge..back in 1975 the heater was rated at 110Volts, between then and now, the new 275 Watt heater is marked 120 volt. So the dif you see on Dometics web page may be old ads not updated. Oh did you see Dometic is relocating from Sweden to Elkhart Ind.??
Great news for us.