Inverter install transfer switch or .....

Hi Mex,

The Dometic fridge, in my rv, starting from an ambient temperature of 18 C (64 f) draws just about 6 kwh measured with a kill-a-watt meter over a 24 hour time frame. I repeated the measurements three times.

If the Dometic fails, it will be history.

MEXICOWANDERER wrote:
I would however suggest that some of you uneager beavers do a cumulative kWh test before pontificating energy requirements to others. EEF is a big factor and so is additional insulation cladding for the replacement.

I run my small 120 V dorm fridge through an inverter. Presently, I don't use a transfer switch. I'm still able to move the male cord end from the shore power receptacle to the inverter receptacle. A simple 15 amp transfer switch wired into the output side of the inverter and changing the wiring for the fridge receptacle would remove the need for swapping the fridge cord between receptacles.

Jack Meyer has all the wiring information on his website.

Initially, I tried to run the fridge on a 600W Samlex inverter but the Samlex could not overcome the startup draw of the fridge. I have since switched to a 1000W Xantrex Prowatt and it handles the load with ease. Measured draw of the fridge during the duty cycle is 80W. Typical cycle is 1:4 at 80 ambient with the door closed and little inside. Typical power usage for a day is .5 KWH= 40-50 AH, depending on door opening amounts, ambient temps, and how full it is.

Good luck with your 120 V fridge!

Have you ever used a UPS on your computer.. This is a box that contains an IN-LINE inverter and battery.. (Well a true UPS is a bit simpler but...)

They make "Inline" inverters.. Most of these double as battery chargers.. Darn good ones as a rule.. Some small ones do not but likely will not power your fridge so we will skip those.

Breaker box-------Inverter------Fridge

IF shore power present--- Charges batteries passes shore power (or generator) to Fridge

IF shore/generator NOT present...Sucks power from batteries to run fridge

NOTE::::: YOU NEED MORE BATTERIES.

I just did the install of an inverter for my residential fridge.

Fridge inverter install thread

That gives you all the good stuff.

Jose

What I know is this...

Remote camping. Hot days. Food spoils with absorbsion refigerator. Sixty-mile trip to buy more perishable food. I figure I managed to toss around three thousand dollars for replacement food and fuel. New NorWork refrigerator. Oh yeah I forgot about adding in oh say six or seven hundred dollars for endless trips back and forth and the chiropractic fees.

The NorWork finally got ripped out by it's roots and tossed out the back door. I can tolerate garbage just so long. The Servel gas refrig's I owned worked perfect for years and years.

I would however suggest that some of you uneager beavers do a cumulative kWh test before pontificating energy requirements to others. EEF is a big factor and so is additional insulation cladding for the replacement. No joke. You could not GIVE ME a new refrigerator for free and 500 dollars to remove my Samsung. And by the way it holds 40% more in the freezer and on a hundred degree day the ice cream comes out of the freezer rock hard. Did I mention the nearest LPG plant is a 132-mile round trip?

naturist wrote:
Do be aware that there is a reason that RVs generally use the absorption refrigerators, not residential units. It is because residential 'fridges (a) do not run on propane and (b) are much more demanding on electric.

A residential 'fridge has a compressor, so that just like your AC, it will draw rather large amounts of power whenever that compressor starts up. You will need a 2,000 watt or larger inverter, and that is going to be quite wasteful of power at all times except for the 2-3 seconds that the compressor is starting. People who are boon docking or otherwise NOT on shore power are not well served by a residential 'fridge for that reason. As others have mentioned, if you go that route, you will have to install a massive battery bank to feed it, and you will have to run a generator a lot every day.

Negative on the power consumption of residential compared to absorption. Residentials use a fraction of the power of an absorption when it is run on electric. Also, on startup a 1000 watt is more than enough. 3 160 watt solar panels provide all the power a residential needs on a normal sunny day. Common misconception.

Hi dons2346,

Actually an absorption fridge has a duty cycle of 2:3 (on for forty minutes per hour). Mine draws 325 watts so the daily resources needed are 5.2 kwh's. A residential fridge such as the Samsung referenced draws less than 1.5 kwh per day.

dons2346 wrote:

naturist wrote:
you will have to install a massive battery bank to feed it, and you will have to run a generator a lot every day.

The above colored statements are not really true. You can use a small 600 watt inverter to power the fridge. You will find that most residential refers will consume about the same amount of watts that a absorption refer will.

naturist wrote:
Do be aware that there is a reason that RVs generally use the absorption refrigerators, not residential units. It is because residential 'fridges (a) do not run on propane and (b)are much more demanding on electric.

A residential 'fridge has a compressor, so that just like your AC, it will draw rather large amounts of power whenever that compressor starts up. You will need a 2,000 watt or larger inverter, and that is going to be quite wasteful of power at all times except for the 2-3 seconds that the compressor is starting. People who are boon docking or otherwise NOT on shore power are not well served by a residential 'fridge for that reason. As others have mentioned, if you go that route, you will have to install a massive battery bank to feed it, and you will have to run a generator a lot every day.

The above colored statements are not really true. You can use a small 600 watt inverter to power the fridge. You will find that most residential refers will consume about the same amount of watts that a absorption refer will. The Samsung that is very popular consumes about 5 watts of power. You do not need a "massive" battery bank to run the refer, most are using a couple of 12 volt batteries or the equivalent in 6 volt systems.

We have a residential refer and are quite comfortable going 8-10 hours without running the generator. The new refers are much better insulated and are capable of going longer without power than the absorption types. We had a problem with the transfer switch and went almost 20 hours without power to the refer and the internal tamp of the refer never got close to 40 degrees and the freezer was still below freezing.

Do be aware that there is a reason that RVs generally use the absorption refrigerators, not residential units. It is because residential 'fridges (a) do not run on propane and (b) are much more demanding on electric.

A residential 'fridge has a compressor, so that just like your AC, it will draw rather large amounts of power whenever that compressor starts up. You will need a 2,000 watt or larger inverter, and that is going to be quite wasteful of power at all times except for the 2-3 seconds that the compressor is starting. People who are boon docking or otherwise NOT on shore power are not well served by a residential 'fridge for that reason. As others have mentioned, if you go that route, you will have to install a massive battery bank to feed it, and you will have to run a generator a lot every day.

The res fridge will mean you need to recharge your batts every day off-grid like Mr Wiz does. Charge for a time in the morning with generator/charger then go to solar the rest of the day.

Deep-cycling the batts every day means new batts every two years maybe, as part of the cost of doing business. They can only do so many deep cycles.

In our set-up, with the "whole house" going to the inverter, the shore power cord plugs into the inverter. If we had shore power, of course then the cord would plug into the pedestal. No transfer switches anywhere! The shore power cord can only plug into one thing at a time (inverter, generator, or pedestal)

http://forums.trailerlife.com/Index.cfm/fuseaction/thread/tid/26237237.cfm