I have read the occasional post regarding the installation of a domestic 240V fridge/freezer into a caravan but cannot find detailed information.
My caravan has a Thetford 184L three way fridge/freezer which works well but, eventually, it will fail and I note a replacement is around $2400! which seems rather on the high side.
I haven't looked in any detail at the technology of modern fridge/freezers but understand they are fairly energy efficient so my question is:
Has anyone installed such a fridge/freezer into a caravan (or a home, I guess?) and taken energy use readings, ideally on days of ambient temperature from, say, 20C to 35C.
Note: for my application freezer use is essential and this takes most of the energy, I usually run my freezer at -12C but manufacturers often fix them at -18C.
All info. welcome.
DeBe said
01:35 PM Aug 17, 2020
I have an LG 310L Linear Inverter fridge at home. The compressor uses the same principal as the Engel fridges. When running the power consumption varies from 12W to 50Watts. On defrost cycle its 150Watts. When the power goes out it will happily run on a 300Watt pure sine wave inverter.
Peter_n_Margaret said
01:45 PM Aug 17, 2020
I am starting a new motorhome build. I bought a second hand inverter Samsung SR227MW for it, https://www.samsung.com/au/refrigerators/top-mount-freezer-rt20farvdww/ but now find I need a LH hinged fridge and this one is RH only, so I need to sell it and find another. This one is available in Adelaide for $220. These smaller Samsung fridge freezers are no longer sold in Australia, but they are still sold in NZ. Power consumption of the small inverter fridge freezers is very reasonable although you must be aware that the condensers are typically in the sides of the cabinet so there must be a space for air circulation. For a 12V fridge freezer the condenser is typically a fan forced radiator alongside the compressor at the back, so it is possible to add extra insulation to the sides to reduce power consumption. That can not be done with the 240V versions.
Nice fridge, but a lot bigger and a lot heavier and needs more power.
Cheers,
Peter
Tony LEE said
07:06 PM Aug 17, 2020
I bought a large LG 2 door inverter fridge for the HINO when the original fridge thermostat failed.
It was close to 1000 dollars but is fantastic.
As for where the condenser is, obviously it is inside the case, but there is no obvious warm spots anywhere so I guess it is everywhere.
We use a time switch to switch it off overnight just to ease up on the loading when solar input is scarce.
One thing to watch is they say not to move it when running so I try to remember. I mentioned it on a US forum a few days ago and it was confirmed that they make a hell of a racket, presumably because the compressor is bashing away at the casing and the only way to get it to stop is to switch it off.
As for power consumption. Never bothered to pick its consumption out of the background usage, but I am well satisfied that it isn't worth worrying about
Whenarewethere said
07:35 PM Aug 17, 2020
We had to buy a new fridge for home. One thing I noticed was the compressor is very loosely mounted & flops around a lot while the fridge is moved. Probably not ideal if using one in a caravan.
A project for possible modifications to make it more secure.
Gundog said
07:57 PM Aug 17, 2020
I have been using a Samsung 228l DI fridge in the van for almost 5 years now, it's paired with a Victron 350Va Inverter, when mains power is not available.
Would I ever consider a 12/24v or 3 way fridge, never in a million years.
Peter_n_Margaret said
09:01 PM Aug 17, 2020
Those small Samsungs have a good reputation in RV applications.
Cheers,
Peter
Scubadoo said
06:11 PM Aug 18, 2020
We have been running a Samsung 255l digital inverter fridge/freezer in our motorhome for the last six years of full-time travel here in NZ.
It is powered by a $100 300W PSW inverter that has operated for the same period 24/7.
We have some seriously corrugated unsealed roads here too.
The original large external Dometic vents are covered with 3mm white opaque acrylic sheet.
The beer is cold and the ice cream hard. Automatic defrosting is a bonus.
I logged the first three years of use. Average 770Wh daily including inverter losses which equates to about 58Ah for our lithium setup.
Expect a little higher in northern Australia.
Mike Harding said
10:47 AM Aug 19, 2020
Thank you very much everyone for your useful input, I really appreciate it :)
The following are some thoughts and numbers I jotted down this morning, comments most welcome:
----
Thoughts and numbers regarding replacing the Thetford 184L three-way fridge with a 240V inverter type unit.
It seems it's possible to run a 220L inverter fridge from a 12V to 240V inverter which means I could do the whole thing via solar:
12V inverter quiescent current = 0A5 or 12Ah or 144Wh.
240V fridge uses about 260kWh per year or 60Ah or 712Wh per day.
180W of solar panel in winter sun in NW Vic produces about 120W real output.
Initial conclusion: If I increase my solar to 430W (panel rating) or 300W (real) and preferably more it should cope most of the time. However this much solar will be a pain to control throughout the day to ensure it's getting good sun.
$1600 is a lot better than $2400 for a replacement 3 way fridge, on-going costs will be very low (generator petrol and new battery occasionally), the fridge/freezer will perform better than a 3 way.
Overall it looks worth doing but I suspect I will spend a lot of time nurse-maiding the solar panels and probably end up running the generator more than I expect.
sgk said
11:10 AM Dec 7, 2021
Hi Mike,
looking at your calculations I think you might have missed the fact that a domestic fridge runs on 240 volt - which I believe leads you to quite an incorrect result.
1: 240V fridge uses about 260kWh per year 2: 260kWh per year = 0.71kWh per day 3: 0.71 kWh at 240 volts per day = 2.958 Amp Hours per day (see www.inchcalculator.com/kwh-to-ah-calculator/)
If I haven't stuffed this up, then your calculated usage is too high by a factor of 20 and a good domestic fridge can actually use less than some dedicated caravan fridges (which matches what I have seen others say during my fridge research).
The digital inverter compressor on digital inverter fridges by the way essentially seems to allow you to reduce the size of the 12 volt > 240v inverter in your van, as it needs less power to start up, which can be useful. But the smallest digital inverter fridge freezer combo I have found is around 250 liters (Samsung), and it is not very energy efficient - see https://www.rpc.com.au/solar-news/selecting-an-efficient-fridge.html. Apart from that my toaster power spikes anyway, so that's not much of a benefit to me.
So if you have a large enough 12>240v inverter then any highly star rated fridge should be acceptable: For consumption by star ratings see https://www.sustainability.vic.gov.au/energy-efficiency-and-reducing-emissions/save-energy-in-the-home/reduce-fridge-and-freezer-costs-at-home
For example the CHiQ 202L Top Mount domestic Refrigerator has 4 stars. It costs around $450 and uses around 2.5 Ah per day based on its star rating. Even if you double this on a 40 degree day, you are still looking at a fairly reasonable consumptions.
The Vitrifrigo 130l 12 volt dedicated caravan fridge freezer which I currently have in my van costs around $1300 and uses about 3.75 Ah per day according to its specifications and double that on a 40 degree day.
As these number are quite different from Mike's numbers, I'd be happy for anyone to confirm this. They also contravene what I used to believe, so please verify. If this is correct, I would have bought a 4 star domestic fridge last time.
Steffan
PS: I know this thread is from last year, but I am guessing not many of us have been out and about in a big way, and others might read this too.
-- Edited by sgk on Tuesday 7th of December 2021 12:37:53 PM
Peter_n_Margaret said
12:40 PM Dec 7, 2021
0.71kWh at 12v is about 60Ah. Add another 10% for inverter losses.
Cheers,
Peter
Mike Harding said
12:50 PM Dec 7, 2021
Hi Steffan
My calculations are correct but I failed to explain I was making a switch from 240V to 12V because of the inverter so the 60Ah *at 12V* is correct. It would have been better had I simply stayed with Wh.
If we use a figure of 800Wh per day that should be close to worse case and, guessing, it would be about 500Wh in a Victorian winter.
I now have 800W of solar and am camped in low density forest; I can produce 1kWh on average days and probably double that on sunny days so believe I can now support a 240V domestic fridge with, perhaps, occasional top-ups from the generator.
I agree that finding a small-ish (~200L) inverter fridge freezer is not easy but the big stores do carry a few.
I'll probably do the conversion next winter, it's a fairly big job and will need three people for the lifting I think.
DeBe said
04:51 PM Dec 7, 2021
2 people should handle a modern fridge these days as they are fairly light.
Mike Harding said
06:27 PM Dec 7, 2021
DeBe wrote:
2 people should handle a modern fridge these days as they are fairly light.
Unfortunately I think getting the old one out (and probably the new one in) through the front window will take three :)
Craig1 said
09:03 PM Dec 7, 2021
Oh right said fred, better take the door off, this whole door is gunna have to go, even with the door off we was gettin nowhere, so charlie and me said lets go home.
Mike Harding said
09:16 PM Dec 7, 2021
"We're just gunna 'ave to leave it standing on the landing...."
Mike Harding said
09:24 PM Dec 7, 2021
Many years ago, in London, I helped my brother in law move into a first floor flat. It had a very tight bend in the staircase and there was no way we could get a large table around it.
In the afternoon my BIL went out for a while; whilst he was absent a friend and I roped and hoisted the table in through a window but didn't tell him how we we had got it into the flat.
I have always wondered what he did with it when he moved out :)
yobarr said
10:27 PM Dec 7, 2021
Mike Harding wrote:
Many years ago, in London, I helped my brother in law move into a first floor flat. It had a very tight bend in the staircase and there was no way we could get a large table around it.
In the afternoon my BIL went out for a while; whilst he was absent a friend and I roped and hoisted the table in through a window but didn't tell him how we we had got it into the flat.
I have always wondered what he did with it when he moved out :)
Reminds me of Peter Janson,a "Gentleman" racing driver who had,I think,19 Bathurst starts for best results of 3rd place,and 2 seconds.He lived on the top floor of a Melbourne hotel,but couldn"t get his Grand Piano up the stairs to his home,so he asked the owners if he could "take the roof off the pub". Thinking he was joking,they apparently said "No problem".Come Saturday,the streets near the hotel were closed so cranes could carry out the task. He was/is an amazing man.Cheers
I have read the occasional post regarding the installation of a
domestic 240V fridge/freezer into a caravan but cannot find detailed
information.
My caravan has a Thetford 184L three way fridge/freezer which works
well but, eventually, it will fail and I note a replacement is around
$2400! which seems rather on the high side.
I haven't looked in any detail at the technology of modern
fridge/freezers but understand they are fairly energy efficient so my
question is:
Has anyone installed such a fridge/freezer into a caravan (or a
home, I guess?) and taken energy use readings, ideally on days of
ambient temperature from, say, 20C to 35C.
Note: for my application freezer use is essential and this takes most
of the energy, I usually run my freezer at -12C but manufacturers
often fix them at -18C.
All info. welcome.
I am starting a new motorhome build. I bought a second hand inverter Samsung SR227MW for it, https://www.samsung.com/au/refrigerators/top-mount-freezer-rt20farvdww/ but now find I need a LH hinged fridge and this one is RH only, so I need to sell it and find another.
This one is available in Adelaide for $220.
These smaller Samsung fridge freezers are no longer sold in Australia, but they are still sold in NZ.
Power consumption of the small inverter fridge freezers is very reasonable although you must be aware that the condensers are typically in the sides of the cabinet so there must be a space for air circulation. For a 12V fridge freezer the condenser is typically a fan forced radiator alongside the compressor at the back, so it is possible to add extra insulation to the sides to reduce power consumption. That can not be done with the 240V versions.
Cheers,
Peter
-- Edited by DeBe on Monday 17th of August 2020 05:10:04 PM
Cheers,
Peter
We had to buy a new fridge for home. One thing I noticed was the compressor is very loosely mounted & flops around a lot while the fridge is moved. Probably not ideal if using one in a caravan.
A project for possible modifications to make it more secure.
Cheers,
Peter
Thank you very much everyone for your useful input, I really appreciate it :)
The following are some thoughts and numbers I jotted down this morning,
comments most welcome:
----
Thoughts and numbers regarding replacing the Thetford 184L three-way
fridge with a 240V inverter type unit.
It seems it's possible to run a 220L inverter fridge from a 12V to
240V inverter which means I could do the whole thing via solar:
12V inverter quiescent current = 0A5 or 12Ah or 144Wh.
240V fridge uses about 260kWh per year or 60Ah or 712Wh per day.
180W of solar panel in winter sun in NW Vic produces about 120W real
output.
----
Therefore:
Daily power requirement = 712 + 144 = 856Wh (71Ah)
So 856 / 120 = 7h of good sun required (won't happen).
Add 250W of solar blanket which will produce, say, 180W real output.
180 + 120 = 300W
So 856 / 300 = 2.85h of good sun required - possible.
----
Add a 100Ah (1200Wh) AGM battery into the system and this will
support the fridge for 24h maximum.
On days of no sun running the generator and charging the AGM at 27A
(initially) will take around four hours to recharge - doable.
----
Cost:
100Ah AGM battery = $300
400W inverter (good one) = $300
MPPT controller = $300
Fridge = $400
Total = $1600
----
Initial conclusion:
If I increase my solar to 430W (panel rating) or 300W (real) and
preferably more it should cope most of the time. However this much
solar will be a pain to control throughout the day to ensure it's
getting good sun.
$1600 is a lot better than $2400 for a replacement 3 way fridge,
on-going costs will be very low (generator petrol and new battery
occasionally), the fridge/freezer will perform better than a 3 way.
Overall it looks worth doing but I suspect I will spend a lot of time
nurse-maiding the solar panels and probably end up running the
generator more than I expect.
Hi Mike,
looking at your calculations I think you might have missed the fact that a domestic fridge runs on 240 volt - which I believe leads you to quite an incorrect result.
1: 240V fridge uses about 260kWh per year
2: 260kWh per year = 0.71kWh per day
3: 0.71 kWh at 240 volts per day = 2.958 Amp Hours per day (see www.inchcalculator.com/kwh-to-ah-calculator/)
If I haven't stuffed this up, then your calculated usage is too high by a factor of 20 and a good domestic fridge can actually use less than some dedicated caravan fridges (which matches what I have seen others say during my fridge research).
The digital inverter compressor on digital inverter fridges by the way essentially seems to allow you to reduce the size of the 12 volt > 240v inverter in your van, as it needs less power to start up, which can be useful. But the smallest digital inverter fridge freezer combo I have found is around 250 liters (Samsung), and it is not very energy efficient - see https://www.rpc.com.au/solar-news/selecting-an-efficient-fridge.html. Apart from that my toaster power spikes anyway, so that's not much of a benefit to me.
So if you have a large enough 12>240v inverter then any highly star rated fridge should be acceptable: For consumption by star ratings see https://www.sustainability.vic.gov.au/energy-efficiency-and-reducing-emissions/save-energy-in-the-home/reduce-fridge-and-freezer-costs-at-home
For example the CHiQ 202L Top Mount domestic Refrigerator has 4 stars. It costs around $450 and uses around 2.5 Ah per day based on its star rating. Even if you double this on a 40 degree day, you are still looking at a fairly reasonable consumptions.
The Vitrifrigo 130l 12 volt dedicated caravan fridge freezer which I currently have in my van costs around $1300 and uses about 3.75 Ah per day according to its specifications and double that on a 40 degree day.
As these number are quite different from Mike's numbers, I'd be happy for anyone to confirm this. They also contravene what I used to believe, so please verify. If this is correct, I would have bought a 4 star domestic fridge last time.
Steffan
PS: I know this thread is from last year, but I am guessing not many of us have been out and about in a big way, and others might read this too.
-- Edited by sgk on Tuesday 7th of December 2021 12:37:53 PM
Cheers,
Peter
Hi Steffan
My calculations are correct but I failed to explain I was making a switch from 240V to 12V because of the inverter so the 60Ah *at 12V* is correct. It would have been better had I simply stayed with Wh.
If we use a figure of 800Wh per day that should be close to worse case and, guessing, it would be about 500Wh in a Victorian winter.
I now have 800W of solar and am camped in low density forest; I can produce 1kWh on average days and probably double that on sunny days so believe I can now support a 240V domestic fridge with, perhaps, occasional top-ups from the generator.
I agree that finding a small-ish (~200L) inverter fridge freezer is not easy but the big stores do carry a few.
I'll probably do the conversion next winter, it's a fairly big job and will need three people for the lifting I think.
Unfortunately I think getting the old one out (and probably the new one in) through the front window will take three :)
"We're just gunna 'ave to leave it standing on the landing...."
Many years ago, in London, I helped my brother in law move into a first floor flat. It had a very tight bend in the staircase and there was no way we could get a large table around it.
In the afternoon my BIL went out for a while; whilst he was absent a friend and I roped and hoisted the table in through a window but didn't tell him how we we had got it into the flat.
I have always wondered what he did with it when he moved out :)
Reminds me of Peter Janson,a "Gentleman" racing driver who had,I think,19 Bathurst starts for best results of 3rd place,and 2 seconds.He lived on the top floor of a Melbourne hotel,but couldn"t get his Grand Piano up the stairs to his home,so he asked the owners if he could "take the roof off the pub". Thinking he was joking,they apparently said "No problem".Come Saturday,the streets near the hotel were closed so cranes could carry out the task. He was/is an amazing man.Cheers