AC Fridge In Campervan -.Power Consumption Test

[trevskoda]

not retired, just tired :rolleyes2:

Left Dell in 2001 - what about you?

Thanks for a well apointed post,but what a ex dell worker requires now is a long HARD DRIVE to clear the head.:lol-053: :wave:
But do watch you dont put a DISC out.

 

[saxonborg]

Don’t know if you mentioned it anywhere but are you running the tests with the fridge empty, presumably if empty then power consumption will be less when full.

 

[wildebus]

Don’t know if you mentioned it anywhere but are you running the tests with the fridge empty, presumably if empty then power consumption will be less when full.

It is generally thought a filled fridge is more efficient in fact.

Contents of the Fridge .... around 5L of liquid in mix of bottles and cans.


Edit: just did a quick search and found this: thermodynamics - Does an empty refrigerator require more power to stay cold than a full one? - Physics Stack Exchange
only scanned the first few sentences but think it concludes "makes no real world difference"?

 

[witzend]

3 WAY

 

[wildebus]

3 WAY

19th CENTURY TECHNOLOGY

 

[mid4did]

not retired, just tired :rolleyes2:

Left Dell in 2001 - what about you?

Not direct dell,Unisys.Left in 2015 and so glad to delete ,delete delete all those manuals and wipe the hard drive :dance:

 

[Tony Lee]

I'd suggest leaving more testing until the early to mid summer when conditions might be representative enough to provide useful information for those thinking of installing a mains fridge. Then of course the figures will need to be measured from the battery so as to include inverter losses.

 

[wildebus]

I'd suggest leaving more testing until the early to mid summer when conditions might be representative enough to provide useful information for those thinking of installing a mains fridge.

That is actually what I said I am doing

Shame all the info was of no use then as still a bit cold

Then of course the figures will need to be measured from the battery so as to include inverter losses.

figures will need to be measured from the battery? Where were they read from in my testing?

 

[r4dent]

Interested in the make and model of the fridge, the ones I've been looking at seem to 1-2 kWh a day which would give very different results.

Choice of Fridge is key. .... I bought an A++ Energy Rated Fridge. ... reading specs again it is just 80kWh [per annum]
There are not many newish fridges around running at 1-2kWh a day?

I stand corrected and look forward to discovering other wonders of the 21st century. You'll be telling me next that they have invented long life gas mantles.

I look forward to seeing the results when the fridge is in practical use in higher ambient temperatures.

As you say the manufacturers quote 220 wh per day for the fridge plus 240 wh for the inverter giving a total consumption of 460 wh or about 40 ah per day.

Fine for your setup, but marginal for those of us with more modest solar / battery configurations.

Is it possible to install some form of time switch between the battery and the inverter?
Something like 0600- 0900; 1200-1600; 2000- 2400 would reduce the overall consumption by around 130wh per day and I suspect would have no impact on the fridge contents.

Good luck and keep publishing.

 

[colinmd]

Be interesting to see the summer figures to get a direct comparison to a 12v fridge.
For those wanting to install a set up like this in a van, another consideration is if it works when not level.

 

[trevskoda]

My van in summer is easy 36c so wondering how hard the batterys would get hammered.

 

[Dowel]

Shame all the info was of no use then as still a bit cold

Well I for one am very impressed and grateful that you are doing this and publishing your results for all to see. Hardly your fault that it is cold when you are able to do this.
Look forward to seeing results from a warmer period in due course which will give a useful overview of performance through the seasons.

I love this tech stuff although sadly our van could only accommodate a very small fridge. I will have to look to see if very efficient tiny fridges are available. Keep up the good work.

 

[wildcampnewbie]

Well I for one am very impressed and grateful that you are doing this and publishing your results for all to see. Hardly your fault that it is cold when you are able to do this.
Look forward to seeing results from a warmer period in due course which will give a useful overview of performance through the seasons.

I love this tech stuff although sadly our van could only accommodate a very small fridge. I will have to look to see if very efficient tiny fridges are available. Keep up the good work.

Agreed, very interesting and useful information. Thanks for your great work Wildebus.

 

[wildebus]

Be interesting to see the summer figures to get a direct comparison to a 12v fridge.
For those wanting to install a set up like this in a van, another consideration is if it works when not level.

I think the "doesn't work if not level" issue is for gas Fridges? A compressor fridge doesn't have that issue (never did with my 12V one, so can't see why a 240V would be different?)

 

[wildebus]

My van in summer is easy 36c so wondering how hard the batterys would get hammered.

Exactly the same situation for 12V and 240V - and I imagine Gas - Fridges. More work, more energy?

My 12V Compressor Fridge worked fine when the interior temp was 40C+. Batteries (220Ah Bank) coped fine.

The thing is ... when the temperatures increase to the high levels, it is usually due to the weather being better, and that is usually accompanied by Sun - and that makes the Solar work better.
Not quite perpetual motion, but an increase in power consumed due to sunny days also results in an increase in power generated (if you have solar) :idea-007:

 

[wildebus]

Well I for one am very impressed and grateful that you are doing this and publishing your results for all to see. Hardly your fault that it is cold when you are able to do this.
Look forward to seeing results from a warmer period in due course which will give a useful overview of performance through the seasons.

I love this tech stuff although sadly our van could only accommodate a very small fridge. I will have to look to see if very efficient tiny fridges are available. Keep up the good work.

I installed a 93L fridge - which is an undercounter Fridge. There are also A++ rated Mini Fridges - around 40L that would be the same power use and cost around £80 (A Weaco CR-50 is a tad larger and costs £500)

 

[wildebus]

I stand corrected and look forward to discovering other wonders of the 21st century. You'll be telling me next that they have invented long life gas mantles.

I look forward to seeing the results when the fridge is in practical use in higher ambient temperatures.

As you say the manufacturers quote 220 wh per day for the fridge plus 240 wh for the inverter giving a total consumption of 460 wh or about 40 ah per day.

Fine for your setup, but marginal for those of us with more modest solar / battery configurations.

I honestly have no idea what a Gas Mantle is! (this is probably one reason why I steered away from Gas Fridges and Heating!)

I would agree that if you had a typical Leisure battery of say 90Ah, which is commonly fitted (VW fit a 75Ah battery if you specify a factory aux/leisure battery), then an All-Electric Fridge may not be a solution - be it 12V DC or 230V AC[/QUOTE]

Is it possible to install some form of time switch between the battery and the inverter?
Something like 0600- 0900; 1200-1600; 2000- 2400 would reduce the overall consumption by around 130wh per day and I suspect would have no impact on the fridge contents.

Good luck and keep publishing.

This is a very interesting point. Given the pattern of On & Off seems to be very much short bursts of energy followed by a long dormant period (bit like myself in fact ), I was also thinking a way to eliminate a lot of that Inverter Overhead would be to actually have some kind of time-switch for the Inverter.
I actually already use a 200A relay to remotely control the power to the inverter and as that uses a very low power control signal to turn on and off, a basic time-clock with a switch output would work well. You might end up with a little more fridge temp internal fluctuation as it can't turn on EXACTLY when it likes, but I do think it would do the job well enough.

However, my testing has switched to a different setup as I mentioned in the last update - "Day 3" I think it was called. More of that in a minute, but you might like it ....

 

[mistericeman]

I think the "doesn't work if not level" issue is for gas Fridges? A compressor fridge doesn't have that issue (never did with my 12V one, so can't see why a 240V would be different?)

Compressor fridge won't be bothered about level providing that it's not almost flat on its back/side/front where oil can migrate out of the compressor and cause "slugging" as it enters the condensor/evaporator... Or to a point where a piston type (rather than scroll type) is trying to pump oil (liquid) rather than refrigerant in its vapour state.

 

[trevskoda]

Compressor fridge won't be bothered about level providing that it's not almost flat on its back/side/front where oil can migrate out of the compressor and cause "slugging" as it enters the condensor/evaporator... Or to a point where a piston type (rather than scroll type) is trying to pump oil (liquid) rather than refrigerant in its vapour state.

So austrailia is out then.

 

[trevskoda]

Exactly the same situation for 12V and 240V - and I imagine Gas - Fridges. More work, more energy?

My 12V Compressor Fridge worked fine when the interior temp was 40C+. Batteries (220Ah Bank) coped fine.

The thing is ... when the temperatures increase to the high levels, it is usually due to the weather being better, and that is usually accompanied by Sun - and that makes the Solar work better.
Not quite perpetual motion, but an increase in power consumed due to sunny days also results in an increase in power generated (if you have solar) :idea-007:

Yep worked out on average i could get about10/12ah so ove a day from about 11am to 5pm 60ah in total from two 100w panels.vely interesting.