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Small Cabin Forum / Off-Grid Living / solar fridge set up questions and comments
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bad dancer
Member
# Posted: 21 Feb 2017 22:23
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Comments and questions welcome.

Just purchased a mini fridge because I absolutely hate my propane fridge.

Fridge is an Igloo 3.2 cu that is rated at 65 w.
I have it plugged into a kill a watt energy meter and it runs 45 to 50 watts while running and cycles for approx 7 hours per 24 hours based on my energy meter.
I know that these numbers are subjective bassed on ambient temp, door open, how much is in the fridge.

My numbers as I figure.

50 watts at 7 hours at day = 350
350 ÷ 12v = 29 amp per day

I have 360 watts of solar.

I am looking at buying 2 6v batteries at 235 amp hours
At 50 % max discharge I have 117 amp hours available.

I have a 60 watt inverter with a peak surge of 1200w
this shoukd be plenty to run the fridge. Inverter will draw negligible amp.
My guess is about 3-5 amps day.
So 117 amp hours divided by 29 amp = 4.3 days of fridge running without battery charging.

Its a weekend cabin with few visits beyond 4 days.

Solar panels will give me about 20 amp hours on sunny days and I typycally get about 2 hours day of full sun.

Based on my calculations, i should be fine to run the fridge.
I know there will be some efficiency loss througout my equations but my best guess says that this will work well.

What says the collective ?

groingo
Member
# Posted: 21 Feb 2017 23:12
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Should do just fine for weekends.
Might want to add exterior insulation (1 inch styrofoam), sides, top and you may want to comparmentalize the interior of the fridge to reduce the cooling area.

Trulsson
Member
# Posted: 25 Feb 2017 15:52
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Personally I would get a 925 amp battery for $130.00

MtnDon
Member
# Posted: 25 Feb 2017 17:18
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Quoting: Trulsson
I would get a 925 amp battery for $130.00

... such as ....? link?

creeky
Member
# Posted: 25 Feb 2017 20:32
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Must be magic battery day.

Quoting: bad dancer
At 50 % max discharge


Your batteries will last 500 cycles at 50%.
Not giving you a hard time. Just being realistic. your parasitic load on the inverter (is it pure sine?) is around 20wh. so 480/day? 30-40 amps.

I ran a fridge for 4 years on lead. No problem. You should be okay. Just be aware there's more going on there than you mention.

If you get a chance to buy a lithium battery for a good price tho. Grab it. All your equipment will thank you.

hamish
Member
# Posted: 25 Feb 2017 20:35
Reply 


Be careful when considering adding exterior insulation to any cooling appliance, and most non compressor appliances use the outer jacket as for cooling, adding insulation to it just traps the heat in, and can turn a freezer into a nasty swimming pool in no time.

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