Off grid refrigeration

[BigEyePuna]

Anyone living off grid have an opinion on DC powered refrigerators, or ones designed specifically for living off grid (with thicker insulation etc.)? Are they worth the extra money or would it be better to get a modest sized ref at Costco, Amazon, or local retailer for much cheaper and use a large inverter? Maybe even put the ref on its own isolated solar setup and use another inverter for the rest of the house/cabin?

[Tink]

Engel makes a darn efficient dual voltage fridge/freezer available on Amazon, but unsure if they ship here. Had one on my off grid property on the mainland, should have shipped it over instead of garage sale on everything (went with sale of property).

Community begins with Aloha

[terracore]

Many off grid folks use a cheap contraption to turn a chest freezer into a refrigerator because they are 10x more effecient. Has been a frequent topic on here lately.

"Or if you don't have $2000 to spend on a fridge, use one of these or something similar to turn a chest freezer into a refrigerator. Chest freezers use a fraction of the electricity a refrigerator uses to keep food cold:

https://www.amazon.com/Inkbird-Temperatu...tl?ie=UTF8&qid=1493392836&sr=8-1&keywords=freezer+temperature+controller&linkCode=ll1&tag=pw016-20&linkId=0c0aceaf58c4d71a5828476851862406

You can get a reliable chest freezer for around ~$220, then another $35 for the converter probe thing, probably pays for itself (compared to using a standard refrigerator) it's first year. Lots of people on solar using chest freezers in this manner."

http://www.punaweb.org/Forum/topic.asp?whichpage=1&TOPIC_ID=23564#262942

[Mikites]

I am using a device like terracore just mentioned with a stand up freezer, very easy on both battery and inverter. My freezer is a frost free, during the defrost cycle (20mins for every 12 hours of run time) it draws 400watts. Normal cycling on and off startup draw is 120watts, power thru the remainder of the cycle is around 80watts. I disabled the defrost cycle initially but found once the coils got a decent amount of ice on them the efficiency totally tanked. A very modest setup could easily handle keeping your stuff cool, especially if it's a chest freezer or a non frost free model.

[bluesboy]

I'm off-grid.

I first tried a dc fridge. It was used and inexpensive. It required 12v, and my solar system is 24v, so I had to get a voltage converter, which was another $150. Then the control unit went out. Then the compressor broke. It was old and used, after all.

I had a mini-fridge, while i was trying to sort out the problems with the dc fridge. I also dealt with coolers and ice a couple times when things broke and i had to juggle my food and equipment.

I eventually got fed up with it all and bought a small (energy efficient) fridge from home depot. They delivered it. It was so easy. And it still works almost three years later, with no signs of breaking. Knock on wood.

I'd go with the bigger inverter, or the 48v system, or more panels, or more batteries. Buy the same ac appliances most everyone else does, and receive the same convenience. Put the extra money into the solar setup. I'd invest in a diesel generator before I built a second, independent solar system.

[MarkP]

Bluesboy:
X2

[MattKarma]

There's a little $50 widget called a "Voltage Monitor Relay" you can set it so that once the PV gets over a certain voltage after the controller i.e. 27 volts, the relay clicks on and turns on an inverter into which an icemaker is plugged in. Simple. Haven't gotten around to doing it myself yet.

[MarkP]

My solar charge controller does this for me. It has an auxiliary contact that can be programmed to supply 12 volts to a relay that switches 120 volts AC. That's how I have it set up. You can wire any load to be turned on when the batteries are above a programmed voltage. You could program it to go off PV input voltage to the charge controller but going by battery voltage lets you hold off til the batteries are mostly charged. I suppose you could freeze water daily and let the freezer coast overnight. If you set the freezer as close to freezing as possible and put the jugs of water in the bottom with the food on top you might get refrigeration without freezing the food.

[Jeremy Lutes]

We currently use two Engel MT-45 AC/DC refrigerator/freezers and a single Danby chest freezer converted for operation as a refrigerator.

The Engels use a neat linear compressor that has no startup surge. The Danby uses a standard rotary compressor which draws upwards of 1KW for a few seconds as it starts, but settles down quickly to about 100W running power.

My impression after years of use is that the energy requirements of the two different beasts are about the same, i.e. in terms of watts-per-unit-volume-cooled, it's roughly a wash.

Thus, I'd say that if your off-grid system has enough capacity for a pricey DC fridge, it would be fine with a cheaper standard fridge, as long as the inverter doesn't balk at the 1KW or so start surge.

BTW, the Engels are pricey. The modified Danby gives us almost twice the volume as the pair of Engels, at less than 1/5 the cost.

[Vitus]

I use smallest freezer from Sears. I have two tires with block of ice to act as a thermal mass. It n it off solar. It is essentially a big ice box. It is like a big cooler that you do not need to buy ice for. I run it off excess solar power for four hours a day since I have a tiny solar system. It is not freezing stuff..works great