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Small Cabin Forum / Off-Grid Living / The Mini Fridge Debate
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hitanktank
Member
# Posted: 6 Feb 2013 20:24
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I look all over the net and there are varying opinions on what is the best mini-fridge for off grid cabin living. What are the opinions here?

And mini only, no full size fridges

MtnDon
Member
# Posted: 6 Feb 2013 21:02 - Edited by: MtnDon
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What criteria define "best"?
Low power use?
And how much power is available; off grid?
Ability to keep cold at a certain ambient temperature?
Freezer size?
Cost?

~~~~~~~~~~~~~~~~~~~
The best small refrigerators are ARB, Engel, and National Luna. They are made to run on 12 VDC and be used anywhere. Back country travelers love them as use use phenomenally low amounts of power. They are priced inversely.

I have not seen any small "cube" type fridges that I like as most either use too much power for off grid use or do not have the ability to keep food cold when the temps hit 90 F.

hitanktank
Member
# Posted: 6 Feb 2013 21:38
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sigh

TomChum
Member
# Posted: 7 Feb 2013 00:31 - Edited by: TomChum
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What about taking a garden-variety mini fridge and adding 4 inches of hard styrofoam insulation to the outside?

I'm using a Sundanzer DCR50. It was $700+. It's super-insulated, very efficient (4 amps), kinda big because of the thick insulation, but only holds 1.8 cu ft. MFR claims it uses 114watt-hours per day which is 41 kwh/year. This is truly a low number, I wonder what it's "energy star" rating would be. Its top-loading which is not convenient, but saves the cold because it doesn't dump out the cold air every time you open it.

I'm not sure if it was a good use of the $700 though.

If I had the $700 back I'd spend $500 on a couple 140W solar panels instead, and have PLENTY extra power (280W more) then I could run a $200 fridge. I saw some 3.2cu-ft fridges (twice as big, and side-loading) that used 337kwh/year (8x the power). But it would include a freezer, which the Sundanzer doesn't have. Or I could get a little 2 cu ft fridge for $85 that I could insulate better. I'd look for a more efficient small fridge than a hungry 337 kwh.

And, in the winter, not running the fridge my big panels would gather all the power I need even on overcast days.

Sigh...

Incidentally there are many (example GE 16 cu ft) refrigerators (small full size) that use 300kwh/year (energy star rating).

MtnDon
Member
# Posted: 7 Feb 2013 02:04
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Higher-quality mini fridges use compressors, -- just like full-size refrigerators do -- to regulate temperature. Cheaper models rely on thermoelectric (Peltier) coolers, which use electrical currents to keep cool. Generally speaking, mini fridges that use thermoelectric cooling are sufficient for chilling drinks, but little else. They cannot maintain temperatures below 40 degrees Fahrenheit, the U.S. Department of Agriculture's threshold for safe food storage, and they are not as energy efficient as compact refrigerators that use compressors.

It's important to know which type of cooling system is used before buying a mini fridge, especially if you plan to store food in it. Most thermoelectric mini fridges are identified as such on packaging. If you are unsure, check the product specs: If they state that the unit cools a certain number of degrees below ambient temperature, or that it must be unplugged intermittently, it's a thermoelectric style fridge.

Dillio187
Member
# Posted: 7 Feb 2013 07:43
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a mini-chest freezer conversion into a 'fridge might be worth looking into as well. Like Tom said, it would be top loading which isn't as convenient, but it does save energy as the cold air doesn't fall out every time you open the door. There are conversion thermostats sold on Amazon that you can simply just plug in and go.

241comp
Member
# Posted: 7 Feb 2013 08:57
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I am currently planning on a 5cuft chest freezer such as this with an external controller to adjust the temperature to above freezing. A 5cuft chest freezer can draw as little as 150kwh/year in freezer mode and 1/2 that or less when used with one of these controllers. Top-loading can be a pain for access to food, but it keeps all the cold air in and reduces both temperature fluctuations (ensuring food keeps longer) and energy consumption.

hitanktank
Member
# Posted: 7 Feb 2013 09:09
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Quoting: 241comp
I am currently planning on a 5cuft chest freezer such as this with an external controller to adjust the temperature to above freezing. A 5cuft chest freezer can draw as little as 150kwh/year in freezer mode and 1/2 that or less when used with one of these controllers. Top-loading can be a pain for access to food, but it keeps all the cold air in and reduces both temperature fluctuations (ensuring food keeps longer) and energy consumption.


groovy idea---I like it

rayyy
Member
# Posted: 7 Feb 2013 16:58
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http://www.jcwhitney.com/single-door-flush-mount-refrigerators/p2003208.jcwx?filterid =c2608j8#

this is the one Iv'e got.It works great,but I only run it on propane.The down side is that it need's a good 12 volt power supply for the electronic ignition control.That is a bit of a pain but I have the 12 volt power set up anyways.It probably would be a lot more efficent, like tom says if it had more insulation around it.It has worked flawlessly for one full year now.Been very happy with it.

GomerPile
Member
# Posted: 7 Feb 2013 21:57 - Edited by: GomerPile
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For off grid living the most important thing is power consumption. The fridge is by far the most demanding application since it needs to run 24x7x365 no matter what the weather is like.

Engel makes a series of 12v coolers that are very efficient (I have a small one that is ok). The sundanzer fridge seems to be the gold standard for electric only units. Get used to chest style fridges....sorry!

Forget grid designed small fridges s they are all power hogs.

hitanktank
Member
# Posted: 7 Feb 2013 22:30
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im gonna do the chest style freezer with temp control
I read a bunch more reviews and articles and it seems to be quite efficient power wise

optimistic
Member
# Posted: 7 Feb 2013 22:36
Reply 


Ditto on the chest freezer conversion. I am also planning to do that. I think that people who spend more time in the cabin than the occasional weekender might find it not as comfortable to 'top load' but for myself it seems perfect...

groingo
Member
# Posted: 8 Feb 2013 11:35
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I got rid of the fridge and freezer all together by changing my eating habits, canning my own or canned food, freeze dried or just dried or just fresh food and with that all I need is a cold water (never above 42 degrees) source and a well insulated cooler which can be kept handy and above ground in winter and below ground in summer because of temperature differences and glass canning jars to keep food in because glass conducts cold without insulating.
Been doing it this way for nearly a year now and my fridge is now used for storage of bread and non refrigerated items.
Cost per year....ZERO.

GreatWhiteNorth
# Posted: 8 Feb 2013 11:56
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I agree the chest freezer is very efficient. I use a 7CF chest freezer for a kegerator to keep my homebrew cold. I use a Johnson temp controler to keep temp at 34 degrees. It turns on when temp reaches 37 and shuts off when it achieves the 34 degree cut out temp. Compressor cycles on a few times a day for maybe 30 seconds. Chest freezers are very well insulated so cold loss is very minimal even in summer. Picked up freezer on Craigslist for $100

For reference, since I last moved the freezer it has been on for 102 days(2448 hrs) and has only consumed 18.34 KWH! That averages out to 7.5 watts per hour. With my rate of $.072 per kWH its cost me $1.32 to keep my beer ICE COLD.

I havent calculated this in terms of amp hours or if running on solar as I am still learning the basics on solar ( thanks mtndon ! ) But I am sure the calcs can be done easily. I will be using this set up at my off grid camp in the near future.

hitanktank
Member
# Posted: 8 Feb 2013 15:19
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Quoting: GreatWhiteNorth
I agree the chest freezer is very efficient. I use a 7CF chest freezer for a kegerator to keep my homebrew cold.



lolol atta boy

buckybuck
Member
# Posted: 9 Feb 2013 06:27
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Can we get more specifics from those of you who have modified a chest freezer? For example:

What specific temperature controller did you use?

How did you install it (do you have to drill, wire, and solder, or do the controllers have a probe you can just sneak in under the door)?

Do the controller and freezer play well with modified sine wave inverters?

Is the 7.5 watts per house usage GreatWhiteNorth is seeing typical for chest freezers used this way?

Thanks!

TomChum
Member
# Posted: 9 Feb 2013 12:43
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This is getting to be more interesting......

Quoting: buckybuck
Do the controller and freezer play well with modified sine wave inverters?

This is a good question. For example, my "kill-a-watt" does not work with my "pure sine wave" inverter. I called Kill-a-watt" and they said "it's impossible to ensure that their device will work with all inverters".

A freezer, I assume would work with almost any pure sine inverter, it's just a 'motor' right? I'd like to hear if anyone's using the Johnson Controls A19AAT-2C controller with a "pure sine wave" inverter.

hitanktank
Member
# Posted: 9 Feb 2013 18:56
Reply 


Quoting: TomChum
A freezer, I assume would work with almost any pure sine inverter, it's just a 'motor' right? I'd like to hear if anyone's using the Johnson Controls A19AAT-2C controller with a "pure sine wave" inverter.


would like to hear this also---good point

creeky
Member
# Posted: 26 Feb 2013 18:58
Reply 


the chest freezer looks good. there are a number of excellent articles on the web about how to do it. basically it's just changing the temperature controller. also I've seen some good posts about adding insulation to a regular fridge and moving the air flow out the back of the fridge and into a closet to keep the heated air from the compressor cycle from heating the fridge: excellent reductions in energy use have been noted.

2014 is bringing new energy consumption rules and all fridges will be using less power. so i'm waiting. I want a real fridge. i hate propane fridges. 2 years of hauling propane has been enough for me.

I'm surprised that the killawatt cares about the inverter if it's pure sine. modified I could understand. it uses a timer/clock and that's an issue with modified sine wave.

Of course I'm using a cooler outdoors for my freezer (to keep the rascals out) and a cardboard box as my fridge (next to the "cold" wall in my cabin). It's been working perfectly well. unfortunately it's warming up outside and my freezer is getting a bit warm. dang. gotta barbeque a lot of beef in the next week.
the cost is pretty unbeatable though.

maybe it's time to get me a used freezer. johnson controls eh? my solar system eats 7.5 watts an hour no problem.

bugs
Member
# Posted: 1 Mar 2013 07:18
Reply 


Some of the ideas above are almost bigger than our shack

We have used an 40 litre Mobicool fridge/cooler for a few years and it has given good service (Once it was made mouse proof...but that is another story.) It is an absorption type and works on ac, dc or propane. We use it attached to a barbecue tank. We get almost a full season of weekends (May to Oct) out of one tank. The lady wife can have ice cubes in her G&T if she likes even at +30C.

TheWildMan
Member
# Posted: 1 Mar 2013 08:01
Reply 


has anyone ever considered the tiny DC tailgate cooler? i saw them in a Kmart automotive section, about a square foot in storage area (or cubic foot). plugs into DC accessory outlets and uses only a little power (no freezer, its made to keep a few things cold for tailgate parties and long trips). i considered getting one to hook to my batteries to keep a few things like eggs and cheese cooler in the summer.

Anonymous
# Posted: 1 Mar 2013 22:43
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those only cool something like 40 deg down from ambient. So if it's 90deg out the BEST it can do is 50deg, and that is at BEST. If its not in the sun, and the cooler is never opened.

I suppose it's OK at temps like 65 deg. Basically when you need it most, it doesn't work. Ice lasts pretty long inder the conditions that an electri cooler is tolerable, so might as well use ice. I had one years ago, was not impressed, maybe better now.

unhappy
# Posted: 1 Mar 2013 23:20
Reply 


Same experience here. I'm a gluten for punishment I guess. I see no difference between the first of those that were made about a quarter century ago and todays. Power hungry IMO and as was said when you need them the most they are at their worst.

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