Residential RV refrigerators

KilroyGuy wrote:
Long trips should have no part in the decision. When you are driving the coach, your batteries are constantly being charged, so the inverter is not drawing them down. Additionally, many rigs with residential refrigerators come with an extra pair of house batteries. Now if you boondock, that's the time when you would probably be happier with a traditional gas/electric refrigerator.

You think? I drive a motor home, this means only about 25 feet from the alternator to the house batteries perhaps 30 the way it runs and all good size wire (most of that is like 4ga or heavier).

And the batteries run down if I run the 350 watt Fridge on the inverter.. I know.. I tried it.

Also one thing folks warn about.... That puts a heavy strain on an alternator that may not be up to the task.

For the O/P.. I would carry a generator, as I said, a pair of GC-2's may run the Igloo model I searched all day, but what about tomorrow. A nice portable Genny (Say a Honda EU-1000i) with a Progressive Dynamics 9260. Can recharge 'em without making too much noise. Or a EU-2000i can not only do that, but microwave lunch at the same time.

Hi Mr. Wizard,

600 watts of solar is about $2 per watt installed (DIY). A decent inverter is a further $400.

Any boondocker is going to have a larger than average battery bank, so I don't see that as an additional cost.

Propane is an ongoing expense. Solar is not, other than the lost interest on the initial cost.

Then, as you know all too well, from personal experience, there is the unreliability of absorption technology. I hate having to level the RV in the parking lot when I stop for groceries.

When I was NOT full time I did run my absorption fridge on 120 volts. If I had a residential it would spur me towards increasing my solar harvest.

We Purchased our Newmar last year I was worried about the Res fridge and the battery usage. but to our surprise it will last 48 hours on the battery with no trouble. Which is longer than we would ever need as most trips are FHU. Would never go back to RV style now we lover the Res Fridge. Safe travels

crosscheck wrote:

MrWizard wrote:
i have a residential fridge, and love it
but for the avg RV'r the LP RV fridge is the best option, its the most economical to operate, LP use is minimal, and uses less Battery power

Can you tell us how an absorption fridge uses less energy= more economical than a compressor type?

Dave

Easy
The per BTU cost of propane, is less than the BTU cost of electricity, when you create your own electricity,
when you are boon docking and running a generator to charge batteries
Batteries cost money, fuel cost money, solar costs money,
The time to recoup the up front costs of going residential, , if you are the avg weekend boon dock camper are extensive

If you full-time, Or if you are a full hook RV`r then residential is a good choice
It's all about your RV life style

Hi,

If you wish to run on propane an absorption fridge will consume about 10 pounds per week. If you wish to run on 120 electricity it will consume a whopping 4.8 kwh per day. YMMV.

Mr. Wizard has records going back about 2 years and I believe his major electrical consumer is the fridge--at about 1/4 of the 4.8 kwh or 1.2 kwh per day for his residential fridge.

To run an absorption fridge on 120 volt via solar is barely possible and would require about 1000 watts of solar in perfect solar conditions. Residential would be (again in PERFECT) conditions about 250 watts. My own records suggest that 600 watts would be needed for a residential fridge to be run reliably from solar, with a good sized battery bank.

crosscheck wrote:

MrWizard wrote:
i have a residential fridge, and love it
but for the avg RV'r the LP RV fridge is the best option, its the most economical to operate, LP use is minimal, and uses less Battery power

Can you tell us how an absorption fridge uses less energy= more economical than a compressor type?

Dave

"economical to operate" needs to be expanded a bit in the explanation.

What I think MrWizard was meaning is the ELECTRICAL consumption of a absorbsion fridge is considerable LESS than a residential fridge when operating on PROPANE for those who are boondocking.

Over all a properly chosen residential fridge will only use 90W-100W of electric compared to a absorbsion fridge at 325W at 120V plus a few watts for 12V.

Absorbsion fridge just simply uses 325W worth of propane instead of electric. Some folk believe that this is easier to deal with for boondocking since they carry 40lbs or more of propane which will last a long time.

I personally have used both and to me hands down the residential fridge is superior for keeping my food at a well regulated safe temperature.

But I will have to qualify that for MY USAGE it works well, I don't boondock for days or weeks. Just simply overnight without power while traveling.

One pair of 6V GC batteries supplies my fridge inverter plus some lighting and will support my furnace overnight. Heavy power users may not be able to get two pairs of GC batts to work for them for 24hrs..

Long trips should have no part in the decision. When you are driving the coach, your batteries are constantly being charged, so the inverter is not drawing them down. Additionally, many rigs with residential refrigerators come with an extra pair of house batteries. Now if you boondock, that's the time when you would probably be happier with a traditional gas/electric refrigerator.

danrn wrote:
What I would like to know is if I don't have a generator, and I am dry camping, should I be concerned about the frig? And is the advantage of the residential frig faster cooling?
Thanks

Some math for you and some research instructions:

First: Every electrical appliance has a tag on it, may be molded into the metal, (or stamped) may be rivited on or stuck on, In the case of a Refrigerator there will be some labeling on the box and on a sticker on the door (peal off sticker) that lists the power consumption.. If you do not have an "Average" assume 50 percent duty cycle.

A small "office" type may draw 100 watts.. Big ones more,,, Since I do not .... hold on I'll research.
Looking at an IGLOO 10 Cubic Foot home unit, Top Freezer: They estimate it will consume about 295 KWH per year. or I'd guess about 1KWH per day in an RV (I'm upgrading due to less cooling in an RV and more exposure) Remember though that is the factory estimate.

So a pair of GC-2 batteries is enough to power it 24 hours,, Of course you may need another pair for the other stuff in your house.

If you never boondock, a residential refrigerator makes a certain amount of sense. But if you do boondock from time to time, or if you ever take trips that have you on the road all day for several days in a row, especially if you do not have a generator you can run while traveling, then a standard RV gas/electric refrigerator makes more sense.

Making the most sense of all is to keep and use whatever refrigerator you already have as long as it continues to function as designed. It makes almost no sense whatever to replace a good unit with another one just to get the small advantages that unit might secure.

Since you are looking at a new rig, and presumably could specify the type in the build order, it all depends on how you intend to use the unit. And if either boondocking or long trips are in your plans, the gas/electric RV 'fridge makes more sense than the residential electric-only one.

crosscheck wrote:

MrWizard wrote:
i have a residential fridge, and love it
but for the avg RV'r the LP RV fridge is the best option, its the most economical to operate, LP use is minimal, and uses less Battery power

Can you tell us how an absorption fridge uses less energy= more economical than a compressor type?

Dave

Yes I can tell you. I have a "E-Meter" that carefully measures the amp hours while running my RV. The refrigerator uses about 0.6 amps per hour that it is running on gas. So about 6 or 7 watts per hour. In 24 hours this works out to about 150 - 175 watts. That is less power than a compressor type refrigerator will consume in 1 hour.

However the LP refrigerator will also consume LP gas, typically at a rate of 2,200 Btu's per hour it is running. Typically running 2-5 hours per day in the cooler months and upwards of 20 - 24 hours per day on a 105F day. There is 95,000 Btu's per gallon of fuel, or about enough to run it 45 hours per gallon? This can be 10 to 3 days, depending on the outside air temp.

So from a 12 volt perspective, the electric refrigerator and it's inverter can use 15 to 35 amps per hour, while the LP refrigerator will only use about 10 amp hours per day. The residential refrigerator without ice maker might run 4-5 hours per day. Because it is dumping heat into the already warm 60 - 85F RV, the hours per day do not vary much from winter to summer, unless the RV does not run a air conditioner and will reach 100F or more in the daytime.

If you are parked in a RV park, and running on electric shore power, you will consume a lot less power with a energy star electric refrigerator, about 1/3 to 1/4 the power of a propane refrigerator running on electric.

When boondocking, and running on LP gas, then the propane refrigerator really shines, only using about 10% the electrical power of a electric refrigerator, but will consume a lot of fuel (depends on your value of a lot of fuel though). I would need to fill my 10 gallon tank in the class C about every 2.5 - 3 weeks, while in the class A, it's 18 gallon tank lasts about 6-7 weeks in the summer, when I am not running the furnace.

Fred.