Author Topic: My new solar fridge is "cool" LOL  (Read 328 times)

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gmiller1977

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My new solar fridge is "cool" LOL
« on: April 02, 2021, 09:31:58 pm »
I mentioned in the last PLUG MUG that we are currently at our off-grid cabin.  Good weather (and boredom) dictates that I should be here doing some upgrades to the little place.  We hope to make it our primary residence in the next few years.

One of the most frustrating things about living off grid is refridgeration.  Last year I purchased a really neat chest freezer/fridge/cooler from a company called Unique.  They offer devices that are designed for off grid and low wattage (12/24 volt) input.

This year, and because we are hoping to spend more time up here (what else is there to do?), I made a splash and bought an offgrid fridge/freezer combo (from Unique).  It's looks like a normal refridgerator with a freezer on top, but it uses the same style compressor that the "cooler" I bought from them, does.  I've been running it for about a week now, and it is freaking awesome!

It uses a 12V/24V battery as an input source (I'm using a 12V AGM battery) and I charge it with 2 x 100W solar panels (also at 12V).

Not sure if anyone here is interested in such a thing, but I thought I would share my experiences.

Solar power really is amazing.


Offline ssfc72

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Re: My new solar fridge is "cool" LOL
« Reply #1 on: April 03, 2021, 04:32:30 am »
Thanks for sharing Glen. I don't have an RV or cottage but I still have an interest in the refrigerators that can run on 12 VDC.
I do have one of those portable 12 VDC solid state electronic coolers but they  really struggle at keeping the food, barely cool, in the summer temps.  I also think they are very inefficient and use a lot of current from a battery, for the small amount of cooling that they are capable of.
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gmiller1977

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Re: My new solar fridge is "cool" LOL
« Reply #2 on: April 03, 2021, 06:49:24 pm »
I'm guessing that's a thermoelectric cooler (Koolatron).  They can be really handy when you are on a road trip and want to keep things a bit cooler, but you're right they struggle when they have to compete with serious temperatures.

The units I purchased use special compressor called a Danfoss/Secop compressor.  No idea what is special about it, other than it sips power to keep things cold.

The geek in me just thinks it's neat that I can power a refridgerator with solar power (and the help of a generator with a battery charger on cloudy days).  :)

Offline ssfc72

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Re: My new solar fridge is "cool" LOL
« Reply #3 on: April 04, 2021, 03:13:45 am »
Yes, a thermoelectric cooler.
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Offline Jason

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Re: My new solar fridge is "cool" LOL
« Reply #4 on: April 04, 2021, 02:00:44 pm »
That's very cool. Be interesting to see if it can keep food cool once the summer comes and especially on hot days. You never mentioned the damage! :D
"With all its sham, drudgery, and broken dreams, it is still a beautiful world." - Max Ehrmann, Desiderata

gmiller1977

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Re: My new solar fridge is "cool" LOL
« Reply #5 on: April 05, 2021, 11:19:04 am »
That's very cool. Be interesting to see if it can keep food cool once the summer comes and especially on hot days. You never mentioned the damage! :D

Reviews are quite favourable for when it's hotter out; for sure it will use more power.

I got it from Costco, I believe the cost was $1300 but that also included delivery.  I purchased the extended warrany for an extra $200.  My girls enjoy having icecream up at the cabin LOL

Offline Jason

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Re: My new solar fridge is "cool" LOL
« Reply #6 on: April 05, 2021, 01:25:32 pm »
What I meant is will the solar panels provide enough power at that point? I know the sun will be around more but 200 W seems a little low to be keeping a fridge cool constantly in 30-40 C weather. But honestly, I haven't investigated this much. Let us know.
"With all its sham, drudgery, and broken dreams, it is still a beautiful world." - Max Ehrmann, Desiderata

gmiller1977

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Re: My new solar fridge is "cool" LOL
« Reply #7 on: April 05, 2021, 07:16:50 pm »
What I meant is will the solar panels provide enough power at that point? I know the sun will be around more but 200 W seems a little low to be keeping a fridge cool constantly in 30-40 C weather. But honestly, I haven't investigated this much. Let us know.

The rated requirement for the fridge is 200W of power to keep the battery powered, but as you mentioned, the power requirement will go up in the summer as it's warmer.  I figure I'll probably put about 500W of solar power on it to keep the battery topped up.  This will help make up for cloudy days, indirect sunlight, shade from trees, etc.

The fridge consumes 56W of power (at 12V) when running.  A fully charged battery (group 24 or higher) could run it for at least 24 hours.  The battery I have on it now is not a deep cycle battery which would allow for even larger voltage draw and would keep it running at least 50% longer.

Right now, I've got 2 x 40W panels hooked up, and I put a 15A battery charger on it for a couple of hours for it a day (with my inverter generator).  Currently it's costing me about $1.35 a day to run, which, I think is a pretty affordable luxury when you are living in the sticks :)  My girls think so at least.  They have icecream afterall :)


Offline Jason

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Re: My new solar fridge is "cool" LOL
« Reply #8 on: April 05, 2021, 07:59:17 pm »
You're right. It is pretty cool. Other than the generator bit, I'd love to do it myself. :) Maybe I could built a tree house with it.
"With all its sham, drudgery, and broken dreams, it is still a beautiful world." - Max Ehrmann, Desiderata

Offline William

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Re: My new solar fridge is "cool" LOL
« Reply #9 on: April 09, 2021, 01:50:52 pm »
Hi,
I've heard that there are propane-powered refrigerators.  Have you looked into those?  If so, why did you go with battery/solar.  I mean, you'd already have propane up there for BBQ and cooking, no?

gmiller1977

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Re: My new solar fridge is "cool" LOL
« Reply #10 on: April 09, 2021, 09:01:42 pm »
You're right. It is pretty cool. Other than the generator bit, I'd love to do it myself. :) Maybe I could built a tree house with it.

Having a generator in an offgrid environment is a necessity.  The inverter unit I have is super cheap to run (about $2 a day).  All I need to do is clean the air filter and do oil changes.

gmiller1977

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Re: My new solar fridge is "cool" LOL
« Reply #11 on: April 09, 2021, 09:24:17 pm »
Hi,
I've heard that there are propane-powered refrigerators.  Have you looked into those?  If so, why did you go with battery/solar.  I mean, you'd already have propane up there for BBQ and cooking, no?

Propane fridges have been around for a long time.  They use them in RVs (Unique offers them too)... typically a 3 way unit that runs off of 110V/12V/propane.  The compressor needs to support all 3, and as a result isn't typically energy efficient (you're cooling with heat).  They also have a nasty habit of failing.  Propane, although "clean", still clogs up and contaminates lines. 

It also means I have to keep a large amount of propane on property.  A propane fridge uses about 1.3 lbs of propane a day, which means a 20 lbs tank would last just over a couple of weeks.  At $30 a swap, thats $60 just for the fridge/freezer.  Compare that to free solar energy (we are collecting about 6 amps @ 12V right now from about 8am to 4pm) and $15 in gasoline usage here over the last week is a decent cost savings - AND, we run other things while using the generator..... hot water, charging laptops for work, phones, video games, etc.

What's important is having an inverter style generator that can cycle down and conserve fuel.  The open frame generator I have here that throws out LOTS of power (4.5kW good for power tools, etc) uses a LOT of gasoline and isn't economical for long term consumption.  It will go through 20 liters of gas in 10 hours.  Compare that to the 4 litres of gas I use on my inverter over the course of 10 hours (albiet it only puts out 1.7kW)

Keep in mind 1.7kW is a approximately a single circuit in your home... you need to be resourceful and use every watt of power your generator is producing; otherwise you're being wasteful.