Residential refrigerator

Stove, cooktop, refrigerator, microwave, icemaker, etc.
HotRod69
Posts: 21
Joined: Thu Jan 20, 2022 11:31 am

Residential refrigerator

Post by HotRod69 »

Thinking of swapping to residential refrigerator. And running it off my inverter. But not sure how long it would take to run batteries down. 4 12v wet cell batteries and a 2000w inverter.
For when generator can not be run.
Erik&Lorrie
1999 Sahara 35' 300hp 3126b
Toney Alabama
ProCycle
Posts: 135
Joined: Sat Oct 03, 2020 1:28 pm

Re: Residential refrigerator

Post by ProCycle »

It depends on the total amp hour capacity of your batteries and the power requirements of the refrigerator.
We can do the math based on my setup.
If we assume a small fridge requires 200 watts that's roughly 16 amps at 12 volts. I've got a very large set of house batteries with a total capacity of 800 amp hours. To keep the batteries healthy I wouldn't want to run them down below half way. So that gives a usable capacity of 400 amp hours. Divide that by 16 amps the fridge needs and that runs the fridge for 25 hours. Of course the fridge won't run constantly but if it has to run a third or a quarter of the time to stay cold then I would have enough capacity to run it for 3-4 days. That's assuming not using battery power for anything else like running the furnace fan, lights, TV, coffee maker, etc.
Jeff
1997 Ivory Edition 3740 Cat 3126 Allison
TDJohn
Posts: 552
Joined: Sun Oct 27, 2019 11:34 pm

Re: Residential refrigerator

Post by TDJohn »

Erik,

Do you plan to do a lot of boondocking?

If your batteries are the 12v marine deep cycle type, they don't have much of a capacity and don't last long for true deep cycle use. So, if you do plan to do a lot of boondocking, you are better of to upgrading to four 6v golf cart (true deep cycle) batteries. There not only have more capacity but have much thicker plates, which equals longer life. You would also be better of with what you have, as the absorption cooling type refrigerators use very little electricity when running on propane. If you want to install a residential unit, then installing solar panels on your roof would significantly cut down on your generator use, especially if you go with a 1000+ watts. Without solar, you would be running that generator for a few hours a day every day. All stuff to consider.
If your current unit is a bit sluggish, you can install small 12v computer type fans on the evaporator coils inside the refrigerator. This will help a lot with circulating the cool air around, making the refrigerator work more efficiently. You can also install larger 12v fans behind the refrigerator to help cool the condenser coil.
John
'95 Serengeti, Cummins C8.3-300
Allison 6spd.
HotRod69
Posts: 21
Joined: Thu Jan 20, 2022 11:31 am

Re: Residential refrigerator

Post by HotRod69 »

the fridge I'm looking at is a magic chef 10.1cf. The numbers I'm finding are 29.7 kwh/year.
1.4 amps on start up
1.3 amps running
90watts running
130 watts on defrost. I'm thinking this should be fine on my 2000w inverter. Only looking to power fridge off the inverter when genny can't be run. Coach should run fridge and charge batteries while driving if I'm correct. Same with genny if no shore power. Only looking for 20 or so hours at most running off inverter.
Erik&Lorrie
1999 Sahara 35' 300hp 3126b
Toney Alabama
ProCycle
Posts: 135
Joined: Sat Oct 03, 2020 1:28 pm

Re: Residential refrigerator

Post by ProCycle »

A 2000 watt inverter will have plenty of power to run the fridge. Is it a pure sine wave inverter? The compressor motor in the fridge might not run very well on modified sine wave power.
Jeff
1997 Ivory Edition 3740 Cat 3126 Allison
HotRod69
Posts: 21
Joined: Thu Jan 20, 2022 11:31 am

Re: Residential refrigerator

Post by HotRod69 »

Guess I'll go 12v. Have modified swine wave inverter.
Now which 12v refrigerator do I get?
Erik&Lorrie
1999 Sahara 35' 300hp 3126b
Toney Alabama
TDJohn
Posts: 552
Joined: Sun Oct 27, 2019 11:34 pm

Re: Residential refrigerator

Post by TDJohn »

HotRod69 wrote: Sun Jan 23, 2022 2:31 pm Guess I'll go 12v. Have modified swine wave inverter.
Now which 12v refrigerator do I get?
Everchill makes a few different size 12v refrigerators, one of our members has one, seems to be happy with it.

Here are some specs to their 10.7 cu/ft refrigerator:

Voltage: 12V DC
Dimensions: 23 1/2"W - 25 3/4"D - 59 3/4"H
Interior: 10.7 cubic feet
Weight: 119 lbs.

Here is a link to one of the sites that sells them:

https://www.wayinterglobal.com/collecti ... less-steel

Here is a link to the same brand 12v unit, but its a bit bigger capacity (11.4 cu/ft), it is 2.25 inches deeper then the 10.7 cu/ft unit.

https://www.wayinterglobal.com/collecti ... frigerator

Etrailer sells these refrigerators too. I'm sure there are other brands too, google is your friend. In case you're not aware, there is also a company in Indiana that makes 12v compressor type cooling units that can be directly retrofit into original equipment RV absorption unit refrigerators, so that might be something of interest to you.

Your batteries should be able to handle this refrigerator for 20 hours just fine. If you will be running other loads also, I would suggest getting a shunt based battery meter like Bogart Engineering's Trimetric 2030RV. It will show you exactly how much power is taken from the battery and replaced (when charging). It will show it in amp hours and percent charged, very easy to use. It is also very handy in seeing phantom parasitic drains that coaches often have. Bogart Engineering also manufacture solar charge controllers that work in conjunction with the Trimetric, resulting in a very effective and efficient solar charging. One or two 200W panels with Bogart's units will give you a very effective low cost solar to help keep things topped off and minimize generator run time.
John
'95 Serengeti, Cummins C8.3-300
Allison 6spd.
Safaritoonces
Posts: 215
Joined: Sat Nov 02, 2019 9:51 am
Location: Bowen Island, BC
Contact:

Re: Residential refrigerator

Post by Safaritoonces »

I installed a Haier, the detailed project is on this site. I would recommend upgrading the invertor. They run at 94 - 95% so there is no significant disadvantage to using a 120v fridge and it will give you a lot more options at a lower price. vertical size and depth with handles are the limiting factors. You may eventually decide to replace the invertor anyway, a lot do. I bought mine offshore with shipping it was $800. The quality is excellent. I say this as an electrical engineer having designed these types of systems at a component and circuit board level. The major caveat is... pay by credit card, ship by UPS or Fedex with shipping insurance. Don't even open the box if it has any external damage. Return it. Never ever ship Chinese shipping. It's all friends with a 1000 smiles until..; it goes wrong. As Bill says "ask me how I know". These invertors are all made in China and rebranded. China is a world leader in solar and power inverters. You can pay $2000+ or $800 + due dilligence.
Robert and Bev Lewis
2000 Safari Continental, since 2017
3126B Cat, 330hp
MD3060 Allison
Bowen Island, BC

https://safaritoonces.org/
TDJohn
Posts: 552
Joined: Sun Oct 27, 2019 11:34 pm

Re: Residential refrigerator

Post by TDJohn »

Safaritoonces wrote: Mon Jan 24, 2022 11:29 am I installed a Haier, the detailed project is on this site. I would recommend upgrading the invertor. They run at 94 - 95% so there is no significant disadvantage to using a 120v fridge and it will give you a lot more options at a lower price. vertical size and depth with handles are the limiting factors. You may eventually decide to replace the invertor anyway, a lot do. I bought mine offshore with shipping it was $800. The quality is excellent. I say this as an electrical engineer having designed these types of systems at a component and circuit board level. The major caveat is... pay by credit card, ship by UPS or Fedex with shipping insurance. Don't even open the box if it has any external damage. Return it. Never ever ship Chinese shipping. It's all friends with a 1000 smiles until..; it goes wrong. As Bill says "ask me how I know". These invertors are all made in China and rebranded. China is a world leader in solar and power inverters. You can pay $2000+ or $800 + due dilligence.
Robert,

For Erik's circumstances you have a very valid point, but for one who wants to boondock the majority of the time, there is a big difference between having a residential refrigerator running on 120v vs a unit that can run on 12v. To start with, inverter efficiency loss, plus the inverter having to be on 24/7. Also, with inverter on, unless a small unit is dedicated to refrigerator only, there will be plenty of parasitic/phantom loads that will eat up amp hours through the night and cloudy days (ask me how I know). BTW, the majority of off grid inverters in use in the US are made in Europe. There is a good reason for this

BTW, China makes plenty of garbage inverters, few are decent but often lack consistency on quality. Europe and US are actually the leaders in top quality inverters, sadly in US there are only a few companies left you manufacture their inverters in US. One company left that still manufactures inverters stateside, is Magnum Energy, and their stuff has been top notch for decades. Yes, majority of inverters are produced in China, but that doesn't mean they are the world leader in quality, far from it. Take a look for an example, the many older Safaris and other coaches that are still using the old, black, dog house shaped, Heart Interface inverters, 25 to 30 years later, they are still working under harsh environments. Sadly, they were bought out by Xantrex and are now made in China. Will your unit last 30 years under harsh use? Only time will tell, but I doubt it...
As far as solar panels go, yes, I agree, they are the leaders on solar panels and have improved the technology by leaps and bounds. Solar charge controllers, like inverters, no so much. Again, US and Europe outperform in quality and efficiency on solar charge controllers. As the saying goes, "you get what you pay for"...
John
'95 Serengeti, Cummins C8.3-300
Allison 6spd.
Safaritoonces
Posts: 215
Joined: Sat Nov 02, 2019 9:51 am
Location: Bowen Island, BC
Contact:

Re: Residential refrigerator

Post by Safaritoonces »

I agree, you really have to do your research. I took mine apart and it is well made. During shipping from China, UPS China dropped mine from a great height. It was a major horror show getting them to own up to the damage. The very heavy tansformer imprinted the heavy base plate but it still worked. The power reel was arcing and bouncing between both legs for several months unknown to me. The inverter was running hot during that time but never failed. Then the power reel finally totally failed and after correcting the input power the inverter ran normally. For me, that was a major stress test of the inverter. I checked the traces on the boards and they are heavy and the pcb material is high quality. I haven't seen any short cuts and this particular inverter is as good as I've seen from the US. I used to install these systems for computer backup systems in industry.

But this is the only system I found so far. I had 10 different prototype boards manufactured in China and not even one of them worked. I recommended against using China but was overridden. Parts were missing, parts put on backwards, shorted traces every where. I will never do that again. Some systems that are marketed by the government have enforced standards because they are trying to undercut and take over market segments.

I haven't used our system for extended time. Mostly we have driven or stayed at RV parks and not that long to date so I would defer to your expertise. Someday I hope to track the fridge power and find out the measured real daily use. I will post it when I get chance.
Robert and Bev Lewis
2000 Safari Continental, since 2017
3126B Cat, 330hp
MD3060 Allison
Bowen Island, BC

https://safaritoonces.org/
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