# Solar refrigeration question



## budgetprepp-n (Apr 7, 2013)

Hi.
I have been trying to figure out how to have refrigeration with a small off grid solar set up.,, 830 watts 
Problem is refrigerators just take to much juice to run. But from what I have seen on the net it looks like most
people with a smaller solar set up are using small freezers. They take a small freezer and convert it over to a refrigerator 
using a kit that is readability available. It looks like most people that are successfully doing this are using something 
like a 3.5 cubic feet upright style. Is anyone here doing this? 
I'm thinking if I already have a solar set up I might as well look into it. Might be nice to have after SHTF


My goal is Refrigeration, Lights, And Running water hot and cold with no grid.
If I'm going to get ready might as well make it as comfortable as possible.


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## Kauboy (May 12, 2014)

Refrigeration would be quite difficult on a solar-only energy setup.
You'd need to be able to deal with spots of time with no sun.
You would need to consider how much power you will need in your banks to keep it up and running for a week or so with no sun to recharge.
Priorities would certainly shift, you can live without electric lighting for a while to keep the fridge going.
However, if your banks run dry, the contents of your now inoperative fridge will start to heat up again.
I assume this is why most people use freezer units, as you said. They generally have better insulation and seals to keep the cold in longer.

That's still quite a lot of power though...
How many hours can you run your current setup with no sun?


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## paraquack (Mar 1, 2013)

I use a 12 volt fridge. It looks like a good sized cooler and opens from the top like a chest freezer to help keep the cold in. Portable Fridges - NRF-60 - PPL Motor Homes
Since it operates on 12 volt DC, if your solar system is 12 volt, there is no loss of power while converting the solar power to AC. Mine is a little smaller and older than what is shown here. Mine will also act as a freezer, and good one too. 4 amps @ 12 vdc


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## HuntingHawk (Dec 16, 2012)

Johnson Controls A19AAT-2C Freezer Temperature Controller is what you are thinking of & are about $60 from Amazon.

Chest freezer works better then a frig because when you open the door to a frig the col air goes out the bottom.

My chest freezer is 5 or 7cuft. Don't recall which off hand. A 520watt solar system handles it no problem. Powers it full time. I have 2L plastic bottles I keep in it. For refrigeration in a commercial power loss I can put food in a large cooler & put one or two of the frozen bottles in it. I am only in the chest freezer twice a day to swap out bottles & get food for the next day.
Power draw is only 1.69amp but initial surge draw is over 6amps but that is only seconds.


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## HuntingHawk (Dec 16, 2012)

Contrary to what some might say, even overcast there is still some charge going to the batteries. Times of full moon I even have power from the panels.


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## Kauboy (May 12, 2014)

HuntingHawk said:


> Contrary to what some might say, even overcast there is still some charge going to the batteries. Times of full moon I even have power from the panels.


"Some" is very vague.
I have a digital voltmeter that displays the voltage coming off of the solar cell for my portable power unit.
It has an indicator light that shows when a charge is being sent to a 12v system, which it is calibrated for.
Anything less than 13 volts, and it does not register a charge going to the charge controller.
This might be a result of the panel being smaller than most rooftop ones. I would assume the larger the surface area, the better photon gathering a panel has, and the more effective it can be with less than full sun. Is that true?


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## HuntingHawk (Dec 16, 2012)

Definately true. A 15watt panel may not register enough voltage for the controller to allow any amperage threw. But a 115watt panel probably would.

BTW, I have seen alittle over 2amps at night with a full moon. A trickle charge but nonetheless, power going to the batteries.


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## budgetprepp-n (Apr 7, 2013)

Kauboy said:


> Refrigeration would be quite difficult on a solar-only energy setup.
> You'd need to be able to deal with spots of time with no sun.
> You would need to consider how much power you will need in your banks to keep it up and running for a week or so with no sun to recharge.
> Priorities would certainly shift, you can live without electric lighting for a while to keep the fridge going.
> ...


 I could probably go a week with no sun but I'm only running the house lights and small stuff Like TV, Computer stuff like that.
No frig or washer/Dryer or anything like that.

I have 5 deep cycle batteries when they are full that's a lot of stored energy. 
With just a car battery I can run one of my 100 watt lights for 26 hours so I don't see why I couldn't run a week
just using what I have hooked up now with lights only at night for 10 hours or so.

I only have 300 watts of solar panels so for now I have more batteries than solar power.
It takes a while to get them charged back up if I get behind and use the system at the same time. But I have
two more panels to install they are 265 watt each. so I should have 830 watts when they are added.

In the summer when we have plenty of sun light the batteries go back to full charged every day.
But when winter gets here with the shorter gloomy days it may be different story.

A small basic set up


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## budgetprepp-n (Apr 7, 2013)

Kauboy said:


> "Some" is very vague.
> I have a digital voltmeter that displays the voltage coming off of the solar cell for my portable power unit.
> It has an indicator light that shows when a charge is being sent to a 12v system, which it is calibrated for.
> Anything less than 13 volts, and it does not register a charge going to the charge controller.
> This might be a result of the panel being smaller than most rooftop ones. I would assume the larger the surface area, the better photon gathering a panel has, and the more effective it can be with less than full sun. Is that true?


Boy that's trick question. They have got solar panels that can give out 100 watts that are only 12"x 12" But I guess they are quite 
costly to make. NASA uses that kind of panel on satellites and stuff


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## Kauboy (May 12, 2014)

A fine little setup, indeed.
Very nice.

If you ran a 12v version, like paraquack mentioned, your system should handle it with little problem once those new panels are added.


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## paraquack (Mar 1, 2013)

budgetprepp-n said:


> I could probably go a week with no sun but I'm only running the house lights and small stuff Like TV, Computer stuff like that.
> No frig or washer/Dryer or anything like that.
> 
> I have 5 deep cycle batteries when they are full that's a lot of stored energy.
> ...


Got two questions. Is that wrench still sitting on the battery? Are you doing anything to get rid of hydrogen gas and acid fumes?


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## budgetprepp-n (Apr 7, 2013)

Kauboy said:


> A fine little setup, indeed.
> Very nice.
> 
> If you ran a 12v version, like paraquack mentioned, your system should handle it with little problem once those new panels are added.


When I get the other two panels installed I would like to ad 3 batteries for a total of 8 do you think this would be enough to ad a 
small fig to what I have now?

Also would I be better off with a 12 volt DC frige or would I be better off with a 120 Volt AC and small inverter?
Aren't DC appliances known for using a lot of electric?


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## budgetprepp-n (Apr 7, 2013)

paraquack said:


> Got two questions. Is that wrench still sitting on the battery? Are you doing anything to get rid of hydrogen gas and acid fumes?


 Yes that's wrench,,, I know I know,,,, And yes the fumes are taken care of. The floor under these batteries are part of my decking
You can see the ground between the boards when you look down. The room is well ventilated. 
I have seen a battery go BANG--Very impressive-- Bent the corner of a car hood almost straight up --


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## HuntingHawk (Dec 16, 2012)

Being in the south in the summer, you want large enough to make plenty of ice. A great barter item also.


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## budgetprepp-n (Apr 7, 2013)

HuntingHawk said:


> Being in the south in the summer, you want large enough to make plenty of ice. A great barter item also.


 Yea not to far from here two guys are building an ice house I'm looking forward to next summer to see how
that works out.


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## alterego (Jan 27, 2013)

I Am Wondering About Battery Location. I Thought About My Basement ButA Fire Cabinet And Ventilation Would Be Required For Fumes. Or Placing A Battery Rack In My Garage. The Garage Gets Damn Hot In The Summer And Below Zero In The Winter. The Basement Stays Between Sixty And Seventy Five All The Time. What Do You Guys Think About The Batteries Being In The Extremes.


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## Oddcaliber (Feb 17, 2014)

Have you looked at an RV refrigerator. They are powered 3 ways,120 ac, 12 volt dc, and propane. Yea they do cost but its another option.


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## budgetprepp-n (Apr 7, 2013)

alterego said:


> I Am Wondering About Battery Location. I Thought About My Basement ButA Fire Cabinet And Ventilation Would Be Required For Fumes. Or Placing A Battery Rack In My Garage. The Garage Gets Damn Hot In The Summer And Below Zero In The Winter. The Basement Stays Between Sixty And Seventy Five All The Time. What Do You Guys Think About The Batteries Being In The Extremes.


 The cold didn't seem to affect my batteries. But I thought that the solar panels would get weaker in the cold but
they seemed to really like the cold. They put out a little more in the cold. Surprised me.

I'm also wondering how the cold affects batteries. The one in my truck seems to do fine.


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## HuntingHawk (Dec 16, 2012)

A problem often encured with solar panel installation is they are only 1/2-1" above a roof. That traps heat under them & solar panels produce less the hotter they get.


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## paraquack (Mar 1, 2013)

budgetprepp-n said:


> When I get the other two panels installed I would like to ad 3 batteries for a total of 8 do you think this would be enough to ad a
> small fig to what I have now?
> 
> Also would I be better off with a 12 volt DC frige or would I be better off with a 120 Volt AC and small inverter?
> Aren't DC appliances known for using a lot of electric?


My 12 volt fridge draws 4 amps @ 12 volts per hour of RUN time. The hotter the environment is the longer the run time. I f it were running constantly as if it was sitting in a car with the windows rolled up, the worst scenario would 4 amps time 24 hours = 96 amps or about 1200 watts per day. An inverter will do the job, but you could loose 10% to inefficiency. My last dry camping experience was four days of fishing, running the fridge to freeze my catch. It ran a long weekend with temperature in the high 80s during the day time. If you can keep it in a basement where temp is lower, it'll use less power. If you can run in a basement, one of the solid state coolers might work. They are supposed to cool the inside a max. 40 degrees below the ambient temp. If you have a 60 degree basement, that should give you internal cooling temps down around 20 degrees. They are fairly decent on power consumption but they are kind of small. A true RV fridge/freezer that run on propane and 120 VAC also need 12 VDC for control power. I had a 1997 Dometic that I lost the thermocouple on during a trip back from FL with the freezer packed full of fish/shrimp etc. The best cooling seems to be on propane (MHO) but I used an extension cord to feed power from a 600 watt inverter to the fridge's 120VAC power cord and it ran fine. My recollection was like 1 or 2 amps @120VAC. It always needed a little 12VDC for controls. On propane it needed a chimney system to get rid of flue gases and the heat from the back of the fridge. I bought a new fridge in 2012, cost just under $1000 with shipping from Texas to suburban Chicago, Illinois. OH, propane is like a big pilot light as far as consumption on propane. The only problem I ever had was when the original crapped out after 15 years of near daily service during the summer.


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## PaulS (Mar 11, 2013)

Batteries produce less power in the extreme cold because the chemicals don't react as well near or below freezing. They also take more time to charge when cold. Storing the batteries in the basement would only require an enclosure with a vent to the outside and a fan to push air into the enclosure. You could set the fan up with a 24 hour timer so you could have the fan on intermittently throughout the day and less at night. Mount the fan close to the bottom of the enclosure and the vent near or at the top. Since hydrogen is lighter than air the fan will never be an ignition source and you will get air flow through the box enclosure. The fan could be an old 12 volt computer fan - it doesn't need to move a lot of air and it can be powered by the batteries themselves.


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