using a deepfreeze as a refrigerator

MPH · October 2016

I'v been looking into seeing what it will take to run a refrigerator full time on solar without using much power , and I heard using a deep freeze and changing the thermostat is a good way to do it . Would you just turn the thermostat way up so it runs warmer or do you have to actually change it .

Photowhit · October 2016

Some people have had success by doing just that, "turning the thermostat up" There is an old thread here somewhere, perhaps Bill can find it. Usually you need to replace the thermostat with one designed for a refrigerator range, or add a thermostat, usually a beer/fermentation thermostat with an on/off switch.

You might search through youtube videos...

mathias · October 2016

Hi,
Easily done with this :http://m.banggood.com/STC-1000-220V-All-Purpose-Digital-Temperature-Controller-Sensor-p-91676.html

mathias · October 2016

No need to change the thermostat : just cut the cord and wire this between freezer and plug.
Easy also to come back to a freezer use.

Photowhit · October 2016

mathias said:

Hi,
Easily done with this :http://m.banggood.com/STC-1000-220V-All-Purpose-Digital-Temperature-Controller-Sensor-p-91676.html

They might be in the US or other markets where the standard voltage is 120...

Turns out they do have a 110 volt version;

http://m.banggood.com/STC-1000-110V-Digital-All-Purpose-Temperature-Controller-Thermostat-With-Sensor-p-995333.html

Might also point out if this is your only load on your inverter, that the display will keep your inverter on so might be a net negative, as it will not let your inverter go into 'watch' mode.

Mathias, does this have a settable temperature range?

BB. · October 2016

Type this into Google to search for freezer to fridge conversion threads (discussions) on our forum (the "site:" tag limits searches to a specific website):

site:http://forum.solar-electric.com/ freezer to refrigerator conversion

Some notes--Yes, most freezers cannot use the standard thermostat, they do not go "warm enough" for refrigerator use. Changing the thermostat or using an external AC thermostat (plug freezer into external thermostat) will work fine.

A typical freezer will still require a fairly large AC inverter (1,200 to 1,500 Watts minimum) to start (induction motors on compressors take a lot of starting current)--And need a good size battery bank (400-600 AH @ 12 volts, 200-300 @ 24 volts) to reliably start over time (i.e., as your batteries discharge+age).

One person here used silicone seal to glue plastic channels to the sides of the freezer cabinet to direct condensation to a drain (or you may end up with a puddle at the bottom over time).

Watch for thermal stratification--Food near the top may not be as cold as food near the bottom--A small computer fan plugged into the thermostat to circulate air may help (when the compressor is on, fan is on).

Your spouse may not be happy with having to move baskets around looking for food in a chest freezer...

Overall, on an average installation, you may use something on the order of 250 Watt*Hours per day (about 1/4 of a typical refrigerator/freezer).

-Bill

mathias · October 2016

Yes, you can set your target temp as you wish, plus how much variation allowed before compressor start again, plus a delay to prevent compressor to start to often.

You're right about this tiny load ((4w i think) that needs to be powered all the time, so no search mode for your inverter...

Maybe time to look more into these inverter fridges...

mcgivor · October 2016

Seems nothing is new, tried the freezer as a refrigerator experiment too, a remote thermostat or refrigerator thermostat would have worked but ended up with an inverter refrigerator. If anyone is interested I can record inrush and running current, sadly my Fluke analyzer has died but I do have a good quality clamp on meter to record inrush.

MPH · October 2016

thanks everyone I like the remote thermostat idea , instead of changing the one in the fridge. I do live in the US so the voltage is 110 . I have a large battery bank , I have 8 AGM 155 amp hours battery's , 1240 AH , 6 150 watt solar panels , 900 watts of solar . currently run my salt water reef tank on solar except for some of the lights . It will run the washing machine easily , tried the toaster , and the small deep freeze , they do okay as long as I run them during the day while the sun is out .

mathias · October 2016

Yes, they make 3 versions : 110v, 220v, 12v.

Mph, if i understand right, you have 8 batts in parallel for 12v setup ?
Somebody, or a few, here, will jump to explain why it's not the best !!!

To go back on the external thermostat, i'm very happy with this model (there are others), again only drawback is your inverter on all the time... No search mode...

MPH · October 2016

yes I am running 12 volt in parallel , I thought about 24 volt , what is the best way to run your solar system . My inverter is small and I was thinking of upgrading it so if I did that would be the time to change it . I can always use the same solar panels & batteries , just have to hook them up different . Right now I have a go power 1500 watt inverter with a 2000 watt peak it's an older one the new one's have a 3000 watt peak . was thinking of going with a 3000 watt with a 6000 watt peak . is 24 watt better ?

MPH · October 2016

also what would be a good quality inverter to buy , go power doesn't make a 24 volt inverter .

BB. · October 2016

If you are going with a 3,000 Watt AC inverter--You should be looking at 24 volts minimum, possibly even 48 volts. At 12 volts, you are looking at a lot of current:

3,000 Watts * 1/0.85 inverter eff * 1/10.5 battery cutoff = 336 Amps (2x that for surge current)

And for a 24 volt battery bank, you would need a flooded cell bank of ~600 AH @ 24 volts (or ~1,200 AH @ 12 volts) minimum.

-Bill

using a deepfreeze as a refrigerator

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