Solar powered 12v fridge

[greg1]

I have always thought a 12 v fridge would drain my 2 x110 batteries in no time on solar but have recently been told they are really good alternatives these days. Does anyone have any experience of views if they are now efficient enough

 

[mistericeman]

I have always thought a 12 v fridge would drain my 2 x110 batteries in no time on solar but have recently been told they are really good alternatives these days. Does anyone have any experience of views if they are now efficient enough

As long as its a compressor type rather than Absorbtion or Peltier ....
You should be fine ...
Our 40l Waeco chest type (fridge or freezer mode )
Only draws about 4/5 amps (and that only when actually running )
Our domestic undercounter and Victron eco mode inverter about the same including inverter overheads .

 

[wildebus]

Mine draws around 55W when active and 24 Hour average of about 50Ah. In the summer, you should be able to make that use up with even a fairly basic solar setup.

 

[trevskoda]

Mt 230v through a soft start smart inverter uses 250mA average, running 2 90ah old had lead acids and 200w solar, never been a problem.

 

[Nabsim]

From all the specs I have seen and my own (old Waeco) I would say work on a 12v fridge using 24 amps per 24 hours and a 12v fridge freezer using 48 amps per 24 hours. I have seen some specs that are worse so look for known brands. Size doesn't seem to matter although the initial power usage to get it down to temperature would probably be a bit more but I only notice continues running.

From the tests David did the 230V appliances run off an investor are along the same lines.

I have seen people on Facebook and other places saying their fridges use nothing, I don't believe them. I do know people who turn their fridge off at night, obviously that would mean it used less power. Mine is on 24/7/365 except when I defrost it

 

[wildebus]

From all the specs I have seen and my own (old Waeco) I would say work on a 12v fridge using 24 amps per 24 hours and a 12v fridge freezer using 48 amps per 24 hours. I have seen some specs that are worse so look for known brands. Size doesn't seem to matter although the initial power usage to get it down to temperature would probably be a bit more but I only notice continues running.

From the tests David did the 230V appliances run off an investor are along the same lines.

I found the 240V Compressors slightly more efficient than the 12V ones; but factor in the inverter overhead and net result was slightly less efficient. The difference in power use can be reversed if you open the door a couple of extra times, it is that close.
I can see the amount of power my fridge/freezer uses and I see the effect on the power on those days when I 'reload' it - even though I am careful to try and minimize door-open times. HOW the fridge is used has probably more impact than the compressor efficiency! (I keep stuff in little baskets and bring the basket out and close the door again rather than rummaging with the door open).

I have seen people on Facebook and other places saying their fridges use nothing, I don't believe them. I do know people who turn their fridge off at night, obviously that would mean it used less power. Mine is on 24/7/365 except when I defrost it

I used to have this kind of discussion with some VW Camper folk ... they would use their fridge for a full festival weekend on a little 80Ah battery no problem
Except .... their "weekend" started on a Friday Evening with a full battery and frozen water bottles in the Fridge; fridge turned off overnight and the "weekend" ending on Sunday morning when the last of the bacon and sausages were eaten for breakfast.
Their full weekend was probably less than 24 hours of being switched on

 

[Fisherman]

If you want to spend prolonged periods off grid with a 120L fridge as we do there really only is one choice, and it’s an absorption fridge.
On average a 120L fridge will use to much power. Not so much in summer when if it’s sunny, our 330W of solar and two 100ah lithium should cope, but in winter with little solar we would be struggling.
Compressor fridges are better than absorption no arguments there, but I don’t fancy leaving my fridge off at night, and having to carefully monitor how much power it’s drawing.
Rapido have since replaced our absorption fridge with a 122L compressor. According to the spec it averages 3.8ah consumption, that’s a 100ah a day. They now fit a second hab battery as standard to cope with the new compressor fridge.

 

[1 Cup]

Cool

 

[trevskoda]

I must state that my fridge is a tiny bench top unit, ok if near shops and can top up when required, big fridges are better for folk going into the wilds for long stays.
All in ours is milk / lemonade and maybe a pezza etc, but it does the job.

 

[aderowswell]

I have a Vitrifrigo compressor fridge and it’s excellent and we only have the one battery in our VW 1974 campervan (a dual purpose AGM 110ah). I use a 100w solar and it keeps the battery topped up very nicely. https://www.vitrifrigo.com/ww/en/c180-ocx2-single-refrigerator-compartment_4

 

[wildebus]

If you want to spend prolonged periods off grid with a 120L fridge as we do there really only is one choice, and it’s an absorption fridge.
On average a 120L fridge will use to much power. Not so much in summer when if it’s sunny, our 330W of solar and two 100ah lithium should cope, but in winter with little solar we would be struggling.
Compressor fridges are better than absorption no arguments there, but I don’t fancy leaving my fridge off at night, and having to carefully monitor how much power it’s drawing.
Rapido have since replaced our absorption fridge with a 122L compressor. According to the spec it averages 3.8ah consumption, that’s a 100ah a day. They now fit a second hab battery as standard to cope with the new compressor fridge.

That is a hungry fridge! - Are you sure that is not the consumption when running rather than a daily average consumption? (the way the numbers are published can be misleading often).

 

[Fisherman]

That is a hungry fridge! - Are you sure that is not the consumption when running rather than a daily average consumption? (the way the numbers are published can be misleading often).

I’m not sure David, but I was chatting to someone with a large compressor fridge and they quoted something similar. They decided to go the lithium route in order to cope with the supply demand. I would love a compressor fridge instead of what I have, but that’s what puts me off.

 

[wildebus]

I’m not sure David, but I was chatting to someone with a large compressor fridge and they quoted something similar. They decided to go the lithium route in order to cope with the supply demand. I would love a compressor fridge instead of what I have, but that’s what puts me off.

It is such a shame that the 3-ways are so poor on electric Given how you use your motorhome and the seasons you use it in, I think the 3-way is sadly the best current solution in your case to have an always-available fridge as the solar will be too much of an unknown outside summer.

I'll just throw up a couple of charts to compare a Compressor Fridge/Freezer (my 240V LEC Domestic one) and a 3-Way running on 240V fitted in a 2021 Malibu. These are the same time-line (the last 12 hours) and both are down to temp and so in the most energy efficient temp control.
Nearly 4 times the power use when running, and it runs more than 50% of the time compare to the Compressor that runs around 1/3rd of the time or less. This shows why the 3-way is genrally a non-starter for off-grid use unless you have a good battery bank and a known limited use-time

Compressor

3-Way on AC

 

[SquirrellCook]

Betty got a fridge today. https://www.diy.com/departments/ige...VI4hQBh1DLASgEAQYAyABEgIR6vD_BwE&gclsrc=aw.ds

It even came with free dents!, so going back again.

Mark

 

[Fisherman]

It is such a shame that the 3-ways are so poor on electric Given how you use your motorhome and the seasons you use it in, I think the 3-way is sadly the best current solution in your case to have an always-available fridge as the solar will be too much of an unknown outside summer.

I'll just throw up a couple of charts to compare a Compressor Fridge/Freezer (my 240V LEC Domestic one) and a 3-Way running on 240V fitted in a 2021 Malibu. These are the same time-line (the last 12 hours) and both are down to temp and so in the most energy efficient temp control.
Nearly 4 times the power use when running, and it runs more than 50% of the time compare to the Compressor that runs around 1/3rd of the time or less. This shows why the 3-way is genrally a non-starter for off-grid use unless you have a good battery bank and a known limited use-time

Compressor
View attachment 131596

3-Way on AC
View attachment 131598

I just checked David, and Rapido reckon on an average day their 122L compressor fridge will draw 60ah in 24 hours. That’s more than you would have available in a 100ah lead battery per day.
I could not agree more David, as you know my current absorption fridge draws 16ah when on leccy. Hence the issues which I had with the smart alternator.
There’s no doubt in my mind what’s the best fridge, but we can go 7 days in winter miles away from shops, and no EHU, and need a larger fridge. Sadly for us it has to be an absorption fridge, particularly in winter. But I am envious of those who can make do with a compressor fridge.

 

[wildebus]

Betty got a fridge today. https://www.diy.com/departments/ige...VI4hQBh1DLASgEAQYAyABEgIR6vD_BwE&gclsrc=aw.ds

It even came with free dents!, so going back again.

Mark

My first fridge came with a dented door and broken salad tray
seller said take it down the recycling centre and sent me another!
sold the dented one for £70

 

[Fisherman]

My first fridge came with a dented door and broken salad tray
seller said take it down the recycling centre and sent me another!
sold the dented one for £70

I want my £70 back

 

[SquirrellCook]

Before I went home last night I plugged the dented fridge into Betty and switched the inverter on.
It looks like during it's "on" period it draws about 36 Watts.
The sampling rate is quite course, so I'm not seeing the peak startup current.
Even with the miserable weather this morning the solar has got me back to 98.5%
At least something is still working after all this time.

Mark

 

[1807truckman]

We run a Thetford 2152 12v compressor fridge/freezer 133L fridge/17L freezer and the quoted average consumption is 39.1Ah/24h

 

[JQB]

I have always thought a 12 v fridge would drain my 2 x110 batteries in no time on solar but have recently been told they are really good alternatives these days. Does anyone have any experience of views if they are now efficient enough

We have 2x100w PV + 2x110 agm + truma. In the cloudy wet dead of winter if we don't move on we have to run the engine for a bit depends.