# 12 volt refrigerator - questions from a beginner



## Piney Woods (Jul 5, 2006)

I am looking at this 12 volt (trucker's) refrigerator. 

http://www.truckfridge.com/tf130acdc.html


It says it is 60 watts. So does that mean if I buy a 60 watt solar panel set up (like this) that it will only run the refrigerator? 

https://www.amazon.com/Renogy-Watts...52403&sr=8-1&keywords=60+watt+solar+panel+kit

Will I need to buy additional panels, etc. to run a few LED lights and 12 volt fans?

I will be building a small cabin and would just as soon have it be off grid / solar / 12 volt. I'm a woman of simple needs.

Thanks for your input.


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## wy_white_wolf (Oct 14, 2004)

The 60 watt panel will not even run the frig. You need to calculate in watthours.

The frig will use 60W x 24hours = 1440WH (WattHours) in a day.

But the panel only produces full power when the sun is shining directly at it. So If you have 4 hours insolation (different than the sun shining) in your area it will produce:

60W x 4H = 240WH or about 1/5 of what you need.

To make it even worse you need to calculate in for system losses. With a PWM controller you loose about 33% and about 10% with an MPPT. So that 240WH produced could only be about 160WH usable with a PWM controller or about 1/9 of what you'd need.

You'll also need to size the batteries to the load.

WWW


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## Gary in ohio (May 11, 2002)

YOu need to to look at fridge designed for solar use. A trucker frige is just a small fridge and they assume you have power most of the time. Not the same with solar power. A solar designed fridge is going to be more effecient even if it uses the same 60watts of power.


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## HermitJohn (May 10, 2002)

Most small refrigerators are very poorly insulated and their compressor runs early and often. The solar refrigerators are heavily insulated so compressor runs only infrequently. Unfortunately the solar refrigerators are marketed to a small specialty market so prices are high. Limited demand equals high price. Personally I think all refrigerators should be at least insulated to the solar refrigerator specs. Its wouldnt add a lot to manufacturing cost. Problem is it makes them "bulky" so they have much less interior space than a poorly insulated refrigerator with same external size.


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## Steve_S (Feb 25, 2015)

@Piney Woods, have a look at the Dandy & Magic Chef "Apartment fridges". They are 120V but they are very efficient and do not suffer the "Niche Market" pricing.

I have a Danby 10 Cu Foot Stainless fridge, which uses 290 Kwh per Year and the newer ones use less than that now... I bought mine from Costco in 2014 for around $400 and I'm very pleased with it.... Have a peek https://www.danby.com/product-categories/apartment-size-refrigerators/


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## ronjnk (Oct 1, 2011)

wy_white_wolf said:


> The 60 watt panel will not even run the frig. You need to calculate in watthours.
> 
> The frig will use 60W x 24hours = 1440WH (WattHours) in a day.
> 
> WWW


This is the first time I'm trying to use the quotes so forgive me if this fails.

All good advice from others. I just want to point out the above calculation assumes the frig never shuts off and runs continuous. There will be a duty cycle, meaning the frig compressor will shut off for a period of time determined by a thermostat. The more insulated the frig, the less it has to run to keep the interior at the set temperature.


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## arnie (Apr 26, 2012)

have you thought about a propane fridge


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## Steve_S (Feb 25, 2015)

It's a terrible thing that THIS is NOT AVAILABLE IN NORTH AMERICA : 
http://mitticool.com/product/mitticool-refrigerator/ But simple, non-utility using goods which don't feed the money sucking beasts are just not for the "advanced western nations"...


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## FarmerGreen (Dec 11, 2007)

Has anyone tried one of these? The author says it operates on .01 kwh per day.

http://www.builditsolar.com/Projects/Conservation/chest_fridge.pdf


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## wy_white_wolf (Oct 14, 2004)

FarmerGreen said:


> Has anyone tried one of these? The author says it operates on .01 kwh per day.
> 
> http://www.builditsolar.com/Projects/Conservation/chest_fridge.pdf


Some of use did a few years ago when the article first came out and Gary was more active in the forum. About the best we had was in the 250 to 300 WH daily range with 400 to 500 WH daily being more common.

WWW


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## Fire-Man (Apr 30, 2005)

FarmerGreen said:


> Has anyone tried one of these? The author says it operates on .01 kwh per day.
> 
> http://www.builditsolar.com/Projects/Conservation/chest_fridge.pdf


I did, Wal-mart 7cf chest freezer, thermostat out of old fridge, temp range 36 to 42 degree's, test about a month, average 300 watts per day.


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## jwal10 (Jun 5, 2010)

We use an older version of this on a 24v micro-hydro system.

http://www.solarhome.org/SunDanzer-...or24VDC.aspx?gclid=CI2ahJnj-s0CFUeUfgod4z4CEw

It is so efficient we now run the same size freezer also, plus some small fans for other purposes in our cabin since we use 4 6v batteries to make 24v. Set up so only 1 can start and run at a time. I bought both used for less than $100.00 each at a junk store. Being chest type, they don't dump the cold air on the floor every time you open the door. We also only open the freezer once a week, take out what we need for the week. Refrigerator only once a day. We also have a spring house for short term cool storage items like salad, leftovers, vegetables, fruit, drinking water and such.

There are also many resources here to help set up an operating system....James


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## Nimrod (Jun 8, 2010)

arnie said:


> have you thought about a propane fridge


This requires elucidation. 

There are two types of fridges. Some have moving parts (compressors). There is a gas that is contained in tubes and coils. The fridge works by compressing the gas which heats up. The heat is given off outside the fridge to the air. When the gas is allowed to expand inside the fridge it cools off and cools off the inside of the fridge. 

Propane fridges work by magic. It burns propane to heat a mixture of ammonia and water to boiling. Somewhere along the line the condensing gas cools off and cools the inside of the fridge. There are no moving parts. Some propane fridges can also use an electric element to heat the ammonia/water mixture. The fridge can have either a 110 volt or 12 volt element or both.

Fridges in campers are propane and can have 110 or 12 volt or both. There are bigger fridges that are for the home that run on propane.

I salvaged a camper fridge from an old camper. I use it for camping at my new piece of land and expect to use it in the off grid cabin when I build it. It works well but can't cool things off as quickly as a normal fridge so I try not to open the door as often. Meats stay frozen in the freezer but ice cream gets soft. A 20 pound tank of propane lasts 3 weeks of more. 

Camper fridges are relatively cheap. The bigger propane fridges are over $1000.

http://www.ebay.com/itm/LP-Gas-Elec...1-4-cu-ft-Mini-Fridge-RV-Freeze-/111797745147


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## JohnP (Sep 1, 2010)

We've been using one of these http://www.edgestar.com/Edgestar-80-Qt-Portable-Fridge-Freezer-FP861/FP861,default,pd.html for 5 years now. Along with some LED lighting, it runs on 305 watts of panels and 4 golf cart batteries. Also a laptop for watching a movie at night. Amazon is the best for pricing on the above


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## katlupe (Nov 15, 2004)

I have a SunDanzer and am very happy with it. I had two different propane ones, and for the most part I liked them. But nothing compares to the SunDanzer because it is free power due to running off the solar panels and turbine. It uses less power than my energy efficient laptop. In the cold weather, like the whole winter, it never turns on once. That is because I have it in my pantry which is unheated. My kitchen has a wood cook stove in it and that would affect it turning on and off, I think. I lived for 6 years with no refrigeration so I could save up the money to get this one. The food is very cold and I have never had any problem with it. It runs directly off the batteries and does not need the inverter on, so no turning it on and off.


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