Freezer to fridge guys, need a recommendation please!

So I had this BRILLIANT thought that if I got a chest freezer and just set the thermostat to 1 that it would hover right around the freezing mark....

Yeah, not so much... BUT having seen videos of people doing it I know there is some sort of magic relay/thermostat/probe/thingymabober out there that will go between the freezer's compressor/thermostat system and the wall to have it kick on and off at fridge temperatures.

Unfortunately I don't know the terminology involved to even start looking for that magic thermostat/contactor box.

I'm good keeping it all 110v so no inverters or low/high voltage combinations or anything, I just don't know what I'm looking for or what makes one better or worse?

Someone on here knows what I'm talking about, right? Wanna point a guy in the right direction?

Some maybe important details: It draws between 62-74 watts and only gets used 2 weeks a year at the family camping trip. It's a 7cf Magic Chef that I got for $175 new and I really don't want to spend $5000 on a relay for such a cheap freezer.

What about something like this? Would plug into the wall and freezer plugs into it. Temp probe goes in the freezer. There are a few different brands and variations

iPower Variable Duct Inline Fan Speed Adjuster with Temperature Controller for Hydroponics Exhaust Vent Blower, 750W 6A https://a.co/d/d6kFdXQ

I use one of these Ink Birds to control my freezer for use as a refrigerator when I have shore power. I am very happy with it.

The one I link doesn't go low enough, try this one or the one above

BN-LINK Digital Cooling Thermostat Controller for Cooling Device Circulation Box Fans 40-108F 8.3A 1000W https://a.co/d/g3aojh0

I've been using this since 2017 to control a secondary blower on my coal stove with the probe in the plenum(coal on a solar forum, I know crazy ?). Plenum hits x temp it turns the blower on to pull air off the stove, when it hits low temp setpoint it shuts the blower off.

You could use it the same way for a fridgeezer, just set your temps accordingly.

WILLHI WH1436A 10A Temperature Controller 110V Digital Thermostat Switch Sous Vide Controller NTC 10K Sensor Improved Version https://a.co/d/gj536cb

I read somewhere that running a freezer at fridge temps was hard in the equipment to the point of failure.

I also use the Ink Bird lined above, now going on 2 years and it has been great, but it does use 110-120V power, so I run my inverter 24/7 which only uses 16 watts. The Inkbird uses very little power and the chest freezer after start surge only uses 50 watts. With the Inkbird, I set the High Temp at 5C and the Low Temp at 2C and the low cost 7.2 cu ft Danby chest freezer I use cycles between the two temperatures and sips energy.

The other option is a 100% mechanical controller made by Johnson Controllers. It does not require power but it can be expensive and difficult to find and maybe not as fine to dial in for temperature control as the digital Inkbird. But it used to be extremely popular for off grid use. I'd consider it if I could find one for a low cost.

FWIW, I have read a lot on the topic over time and not once have I EVER seen information about running a freezer as a fridge as being hard on the equipment to the point of failure. As well, I emailed the manufacturer on this topic and how to finely dial the stock thermostat and the technician did not warn me against it, only that the stock thermostat could not have fine enough control. I got it within a 10C degree swing, but either just under 0C or up to +10C before I gave up and just bought the Inkbird. The Johnson Control model was over $100 plus shipping and I didn't want to spend that much in case the freezer to fridge didn't work for my needs.

Also, Danby had recently announced a chest Freezer Fridge combination unit that has a thermostat that can be adjusted for either use. I've never looked at the specs to see how technically it might be different than a specific chest freezer or compare their energy use. The cost was about $600 CDN whereas I paid $249 CDN for mine.

Depending on the humidity in your area, chest freezers do not have auto fan defrost, so they can have some or a lot of moisture build up, but should be no problem for short periods in a humid area. My humidity is low, so I only need to remove water with a sponge every few weeks.

Simply turn the freezer up full and control the AC input with an external digital thermostat as linked above ... It's well worth it, externals are much more accurate than the built ins

Get one that has a delay feature or that can offer separate cut in/out temperatures , these digitals are so accurate they can end up turning your freezer on and off 10 times a minute which isn't good for the motor , so if you can let it swing between say 40f & 37f that'll work better


47f & 37f are the absolute outliers temps your fridge should reach



EDIT: I didn't read your post properly lol, thought you were just trying to control a freezer better, not use it as a fridge ..., but this is still interesting:





Another thing you can do with a freezer is stick it on a timer (after the thermostat) and turn if off for 6/8hrs over night, have it turn back on during solar hours so it's not hitting your batteries over night, it'll draw hard when turned back on but if you've got excess solar in the day that's not an issue


If you do want to play the 'turn it off overnight game' , you'll need a separate digital thermometer with max/min & an external probe to keep an eye on the temperature inside , adjust length of time turned off accordingly

Freezers want to stay within 6f to -2f roughly

Put both probe cables inside the fridge, shut the lid on them


Better prices are available:
Digital thermometer (max/min)

Hope that makes sense sorry for the essay

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featherlite said:

I use one of these Ink Birds to control my freezer for use as a refrigerator when I have shore power. I am very happy with it.

Inkbird Digital Temperature Controller Dual Stage Thermostat ITC-308

Inkbird ITC-308 is an easy-to-use dual relay output temperature controller that supports temperature calibration. Heating and cooling equipment can be set up at the same time or separately, and it has compressor delay protection. The controller has multiple alarm functions to ensure safe operation.

inkbird.com

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Thats very similar to the one I use, works perfectly

Look at digikey for electronic thermostats.

It might surprise you that those old fashion analog thermostats that we like to scoff at are remarkably good at temperature control, especially for the range that you are looking at.

The electronic ones tend to be +/- 3 - 5 F.

The very large heat of fusion of water can really help with temperature stabilization.

2 weeks - for a moment I was imagining burning man.

Fwiw generally and post no 7.

May not be relevant to your use case.

InkBird on the way, thanks all!

Rednecktek said:

InkBird on the way, thanks all!

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Costco also sells the 7cuft media convertible chest freezer/frig for 269.99 they were only 169.99 a year ago but even at the 269.99 still a good deal I’ve been running one for five years now freezer version only no problems at all and having a spare in case of a failure was cheep at the old price I ended up buying 4 2 freezer’s only and 2 convertible and have been very pleased something to consider if you haven’t got the chest yet

This is a topic discussed in other circles. Basically switch out the freezer thermostat for a refrigerator thermostat. There are plenty of web sites that discuss this. I did see the InkBird on Amazon and it looks like it is on the way.

I did not find switching the freezer thermostat for a fridge thermostat to be a good solution. Finding parts was not easy here and then there was the main problem of removing the freezer thermo coupler and the difficulty of routing in the replacement refrigerator unit. That can be a real PITA to pull out and replace and it can cause damage to the insulation or interior material and or greatly reduce the accuracy of the refrigerator thermo coupler, if it cannot be re-routed into the correct position. Then trying several or more times to find the correct spot could further damage the insulation with each push or pull. I opted against it when I got to the point of pulling the freezer thermo sensor out as a possible option.

The InkBird digital thermo sensor is so incredibly easy, very accurate and causes zero problems or physical damage and the chest freezer can be returned to stock in an instant.

The InkBird was also similar in price as a refrigerator thermostat that "might" have worked (am not in the USA) but the InkBird would be one hell of a lot easier, more accurate, more elegant and removeable without damage.

E. Cho said:

The InkBird digital thermo sensor is so incredibly easy, very accurate and causes zero problems or visible damage and the chest freezer can be returned to stock in an instant

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These are great selling points. Definitely a lot of improvement since I looked at this last.

Installed the Ink Bird today, worked like a charm. Thanks y'all!

Rednecktek said:

So I had this BRILLIANT thought that if I got a chest freezer and just set the thermostat to 1 that it would hover right around the freezing mark....

Yeah, not so much... BUT having seen videos of people doing it I know there is some sort of magic relay/thermostat/probe/thingymabober out there that will go between the freezer's compressor/thermostat system and the wall to have it kick on and off at fridge temperatures.

Unfortunately I don't know the terminology involved to even start looking for that magic thermostat/contactor box.

I'm good keeping it all 110v so no inverters or low/high voltage combinations or anything, I just don't know what I'm looking for or what makes one better or worse?

Someone on here knows what I'm talking about, right? Wanna point a guy in the right direction?

Some maybe important details: It draws between 62-74 watts and only gets used 2 weeks a year at the family camping trip. It's a 7cf Magic Chef that I got for $175 new and I really don't want to spend $5000 on a relay for such a cheap freezer.

Click to expand...

Never even knew this was possible.

Great thread and information!!

Issue with using a freezer for refrig is the freezer may not run a defrost cycle often enough.

The more ice buildup on cooling evaporator coils the less air flow across cooling coils so it runs longer to cool down air. In a humid environment, >70% relative humidity, this can have a significant impact in less than 24 hours without defrosting.

If you use a temp controller or timer to cut total AC power to freezer you may totally defeat its defrost timer by resetting it every time power is removed. Some units trigger a defrost cycle every time they initially get AC power. This will consume more power if total AC power cut is used to control temperature.

Refrig's normally get opened more often allowing more humidity in.

A freezer with top opening door reduces the amount of outside air exchanged when opened.

Many freezers use a positive temp coefficient thermistor to control the engagement of starter capacitor to compressor. They need at least a 20-30 minute off time to allow thermistor to cool down to reenable start capacitor.

If you attempt restart of compressor before thermistor resistance has dropped back down in resistance you will not get starting boost of start capacitor. Compressor will have longer starting surge current or may even not start up resulting in locked rotor until over temp switch protection disables power to compressor. If this happens it can take a couple of hours before compressor cools down enough to reset over temp cutout switch.

Not exactly pertinent to this thread but adding this info below for those searching for off grid options in the future, that might come across this thread.

Convertible Danby Chest Freezer / Fridge info at the Danby Canada website. I saw a thread today that shows it on sale inside some Costco Canada stores for $249.99 CDN ($186 USD). On the Costco Canada website it shows it at $399.99 CDN. The Energy Star card shows it using 225 KWhr/year but doesn't mention if used as a Freezer or Fridge. I'd expect it to be as a Freezer, as my similar size and rated Danby freezer as a fridge uses less than half the energy of the same freezer set up, so 125 KWhr/year. Although there are variables to this rating, as in how often the lid is open and closed and the ambient room temperature, so the real world use may use more energy or less energy.

Of course there is only the manual defrost option and so use as a fridge, in humid environments, could cause considerable interior condensation that would require either more frequent sponging to remove condensation build up. In my Inkbird controlled conversion, I get very little condensation but I also don't often open and close the converted freezer to chest fridge that often each day.

The advantage with this convertible option is that with a capable inverter, the thermostat does not require power until the temperature control requires it, unlike the Inkbird Digital Thermostat option, which always needs power, however that electricity draw is minor. Also, this thermostat on a freezer will turn on with my old Xantrex SW 4 KW inverter in standby (Search) mode, whereas the Inkbird digital thermometer will not.

It is also a lower cost option than a DC chest freezer fridge and obviously a simpler control than converting an AC Freezer to a Fridge.

I have not seen any info whether the compressor is different or the technology is different other than a different thermostat being used. This to me is a nice off grid small use application option at a pretty low price and FWIW, a 5 year warranty.

Nobodybusiness said:

Never even knew this was possible.

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I searched on the web for a few minutes and found no mini freezers that had the upper temperature range anything near 32F. Too bad, I would like to have one. I currently run a 2.1 Cu Ft mini upright freezer in my trailer. I use it as a refrigerator with a 12v Ink Bird and relay that cycles my 1000 watt inverter on and off.The freezer/fridge uses about 3 amps per hour on average taking into account cycling. I have read that cycling the inverter on and off can be harmful to the inverter. However, after three years of use, the inverter still works fine.

RCinFLA said:

Issue with using a freezer for refrig is the freezer may not run a defrost cycle often enough.

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Fortunately for me it's a really cheap unit without a defrost cycle, just a plug in the front. As long as it keeps the corn dogs cold for the week of camping it can spend the next few months dried out. ?

featherlite said:

I searched on the web for a few minutes and found no mini freezers that had the upper temperature range anything near 32F. Too bad, I would like to have one. I currently run a 2.1 Cu Ft mini upright freezer in my trailer. I use it as a refrigerator with a 12v Ink Bird and relay that cycles my 1000 watt inverter on and off.The freezer/fridge uses about 3 amps per hour on average taking into account cycling. I have read that cycling the inverter on and off can be harmful to the inverter. However, after three years of use, the inverter still works fine.

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I've been reading info for a couple of years on converting a chest freezer into a fridge and just found this option in the last couple of months. So as near as I can tell, it is a new product for Danby. It was not on their website as a product until recently.

I'll pretend that they did this after my back and forth with Danby customer service and technicians of the need for a chest fridge thermostat for off grid users, as there were no other affordable options and their current freezer thermostat inside temperature controls, of which they have 2 (sort of like fine and course setting screws), had too wide a temperature range at settings for a fridge.

I hope that other off grid users also made such a request and Danby listened.

But, unless my present 2 Danby appliances fail, I won't need to buy this new dual mode freezer/fridge. It was much too expensive when I first came across it but it's great news now if this Costco sale indicates the price may be dropping, as it often does for new products. $250 CDN is about my affordability limit.