Most efficient fridge on the planet !!

oldtech

Guest
..... thought that might get your attention ! :pc:

Hi Campers !

I really want a 12 volt compressor fridge with low power consumption.
Waeco do some cracking ones ..... if you want to spend six hundred squid ( or more ! ).

I've been doing lots of research on this topic recently.
You can quite easily turn a chest freezer ( an old one will do ) into a fridge with some very basic wiring changes
..... low voltage wiring as well , no need to mess with the mains supply.

I Googled " Convert a freezer to a fridge " and also did the same on YouTube.
There are some very good articles around ,and also about using fridges with solar power ....
click these links for more info :-

Solar-powered refrigerators by Jeffrey Yago, P.E., CEM Issue #102

Chest Freezer To Fridge Conversion-The Most Energy Efficient Fridge Ever | A Self Sufficient Life

Chest fridge

The big advantages appear to be that freezers are much better insulated than fridges , so the compressor is
running for much less time in any 24 hour period ... ( compressor OFF = ZERO power consumption ).
... AND ... with a "chest-fridge" ,all your cold air doesn't come pouring out everytime you open the door.
As far as I can see , the only real disadvantage is that you might get damp build-up in the bottom of it.

Have any Wildcampers out there actually tried this ?

What about with 12 volt freezers ( do such things actually exist ? ).
Please post a reply if you've had any experiences with this idea .

Thanks

Oldtech
 
Hi Old tech
A very interesting subject Thank you for sharing. I've always wondered whether it was possible to convert a 'work' top small freezer into a fridge it opens up some possibilities. Many thanks
Bye for now
Freddie:wave:
 
Thanks Oldtech, seems to be an idea worth considering. We are the not so happy owners of a £700+ Waeco compressor, almost the biggest single cost in our conversion. Lovely stainless steel job but it will eat a 330Ah battery bank in just over 72 hours (this one is a free replacement from Waeco (now Dometic), the first one was even worse). In our experience their claimed power consumption figures are far too optimistic, and we have it turned down to near minimal cooling. As you say, the insulation on a freezer seems much better. Please share your further experiences because our Waeco has got to go.
 
Have you conisdered a gas fridge? they are cheaper to run but not sure of the logistics of fitting one. We saw several "dented but new" at a boat jumble last year & ex-caravan ones (which also run on 12v while the engine is running) can be picked up cheap (well cheaper than £700!!). We looked at 12v fridges previously and the cost put them out of our price bracket. Your idea makes sense..must be a way. Look forward to hearing how you got on.:cool1:
 
ivecotrucker said:
Thanks Oldtech, seems to be an idea worth considering. We are the not so happy owners of a £700+ Waeco compressor, almost the biggest single cost in our conversion. Lovely stainless steel job but it will eat a 330Ah battery bank in just over 72 hours (this one is a free replacement from Waeco (now Dometic), the first one was even worse). In our experience their claimed power consumption figures are far too optimistic, and we have it turned down to near minimal cooling. As you say, the insulation on a freezer seems much better. Please share your further experiences because our Waeco has got to go.
Click to expand...

Hi Ivecotrucker
thanks for the reply ..... REALLY !

You may have saved me £700 !!!
I saw a Waeco compressor fridge advertised on here ( 2nd hand ) a few months ago , then I got called away
and forgot about it , and by the time I remembered a few weeks later and contacted the seller ..... it was sold.
I was kind of cursing myself for a long time afterwards as I've read some good things about them.
Makes me wonder now if the seller hadn't discovered the same issues as yourselves !!!
It sounds like they may only really be suitable for hooked-up on-site use ..... and that doesn't interest
me at all.

I'm determined to have a solar powered , nearly self-sufficient vehicle for long term wild-camping.
I'm going to look for a small 2nd hand chest freezer and do some experiments " in me shed " .
You are dead right about manufactures claims for power consumption , probably the same as vehicle
manufacturers claims for fuel ...ha ha.
In the States there's something called a "Kill-a-watt meter" which you plug your appliance into , just like
a time switch except that this logs the total power use over any period you choose... only $20 in the USA !!!
I keep seeing stuff about them on solar power forums .....I'm going to try and get one .......... today !!
Anything positive to report and I'll put an update on this forum ....

In the meantime "Happy Camping "

Oldtech

PS just found a UK supplier !! :dance:

£20 + p&p

http://www.reuk.co.uk/Kill-a-Watt.htm
 
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I have seen loads of people try running compressor fridges. Unless you have a roof full of solar panels or a huge bank of batetries it all seems to end in tears. Even if you have 4 or 6 batteries, they will take a lot of charging. Unless the fridge is really tiny they are always going to have a fair current draw. And if lots of insulation you end up with smaller space. 3 way fridges are the way to go - gas is quite efficient.
 
Hello.Just read this post,found it very intresting.So gas is the way to go unless hooked up.cheers.
 
We have a Waeco MDC-110 fridge in our van. I must say it's a great fridge but it does use around 45Ah a day. Our 400Ah of batteries plus 160w of solar panels keep up with it in the summer but we struggle if not on hookup in the winter, when we have to run the heating (Webasto Thermo 90) as well.

If you want optimum electrical power conservation you really need to go for a 3-way gas/12v/mains fridge. However I don't really like them because you have to be pretty level for them to work efficiently and there's those extra holes in the side of the van too.

AndyC
 
Thanks for the Thanks, Oldtech; glad to be of help. I guess you won't want any further info on compressor fridges but if you do then please contact me.
I have not heard of the "Kill-a-watt" meter so cannot comment reliably BUT will it also measure power consumption at only 12v ? Is the internal algorithm not set at 110v (for USA) or 235v (Europe-ish) ?.
Just a warning thought for you, I don't know the answer myself.
 
Hello AndyC,
That is an amazingly good advert for solar panels that a 160w panel can keep up with an MDC110 without running down your main bank.
Our decision to use a compressor was based on:

1) No holes in the side (& to maintain our semi-stealth external appearance)
2) Minimise dependence on noncompatible foreign gas bottles (now overcome by Gaslow type refillables)
3) Easier to install/remove/service without need for effective/safe gas flue sealing (I've seen some fairly dodgy flue arrangements on some well known makes of campervan).
4) Minimise the amount of gas piping & number of unions
5) Better reliability if parked on a slope (but to be fair the '3 way' in our previous vehicle never once played up, even on the steepest of slopes)
 
The biggest problem that I've experienced with 3 way fridges is that they are very sensitive to being absolutely level. The older ones were far worse that the more recent models. I've seen the figure of 5 degrees off vertical bandied about

They also suffer a loss of their cooling ability if the weather goes above a certain temperature; I'm not sur ehow much 30 degrees Centigrade or something like that. Dometic are well aware of this and even produce a supplimentry cooling fan for 3 way units.

The 12vDC comp units were originally designed for the Yotties as they never seem to be on an even keel. This was, until recently, a very small market as the majority of yachts didn't have room for a fridge. Now the Motorhome/Caravan/Barge people have also shown an interest the prices have come down marginally. Yachts also tend to carry a larger battery bank than Motorhomes or Caravans. They will tend to also have both wind gennys, engine alterantor and solar as a means of recharging

I've run both and have a 3way fridge freezer at present and I think it's useless compared to my previous 12v Comp units
 
ivecotrucker said:
Thanks for the Thanks, Oldtech; glad to be of help. I guess you won't want any further info on compressor fridges but if you do then please contact me.
I have not heard of the "Kill-a-watt" meter so cannot comment reliably BUT will it also measure power consumption at only 12v ? Is the internal algorithm not set at 110v (for USA) or 235v (Europe-ish) ?.
Just a warning thought for you, I don't know the answer myself.
Click to expand...

Yeah , you are spot on there Ivecotrucker !
The UK version has a standard Brit 3 -pin plug on the back of the unit
and a Brit socket on the front to plug-in the appliance to be monitored.

There IS an effective , and relatively cheap meter to do the same for 12Volt DC.
I came across it while reading an American solar energy Forum.
I noted down the link ..... ( somewhere ...:confused: !! )
If you want it , get back to me and I'll search for it.

If someone is using solar panels + leisure batteries + inverter , then with the two monitoring systems
together , you could do a really accurate analysis on your whole power system ......
.... for relatively little cash outlay .... and it may pay for itself in energy savings.
Got to be better than changing appliances just because of suspicions about excessive power consumption !

Anyways , you clearly have your brain switched ON .... always nice to see !!

All the best

OT
 
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Hello again Oldtech,
I am currently (!!) looking into Amp-Hour counters @ 12v so IF you find your info source please post it - but please don't spend hours looking for it.
Still got the 'Throw Over Inductance Coil' design on my drawing board (aka scrap of paper) -
a) how to launch it over an 80-100'+ high line ?
b) how recover it ?
c) how to measure the overhead HT voltage & hence calculate correct number of inductance turns ?

If Benjamin Franklin harnessed a thunder cloud with a kite, some string & an old key (& lived to tell the tale) then I reckon my idea is a doddle. Perhaps I need a FLASH of inspiration ?.
 
DC Power Metering

ivecotrucker said:
Hello again Oldtech,
I am currently (!!) looking into Amp-Hour counters @ 12v so IF you find your info source please post it - but please don't spend hours looking for it.
Still got the 'Throw Over Inductance Coil' design on my drawing board (aka scrap of paper) -
a) how to launch it over an 80-100'+ high line ?
b) how recover it ?
c) how to measure the overhead HT voltage & hence calculate correct number of inductance turns ?

If Benjamin Franklin harnessed a thunder cloud with a kite, some string & an old key (& lived to tell the tale) then I reckon my idea is a doddle. Perhaps I need a FLASH of inspiration ?.
Click to expand...

BINGO !

I keep lists of websites / links that were interesting but didn't merit a bookmark of their own.....

..... the one I mentioned to you was in the second place I looked ...easy peasy !

DC Watt Hour Meter

RV & Marine Battery Monitor

It's an American site but I usually manage to find the same stuff in UK / Europe after a bit of searching...
eg the "Kill-a-watt" meter .... and I've found 3 similar devices for less money since I first mentioned it in a post .

Let me know how you get on ..

regards

Oldtech
 
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Thanks to Oldtech & Wildman.

Now, has anyone any ACTUAL experience of these gizmos, &, most importantly, how accurate are their 'predictions' of battery "State of Charge" & "Remaining Amp Hours" ?. There is quite a bit of guff available from manufacturers & retailers but also various comments that they don't work.

Your comments please Gentlemen.
 
ivecotrucker said:
Thanks to Oldtech & Wildman.

Now, has anyone any ACTUAL experience of these gizmos, &, most importantly, how accurate are their 'predictions' of battery "State of Charge" & "Remaining Amp Hours" ?. There is quite a bit of guff available from manufacturers & retailers but also various comments that they don't work.

Your comments please Gentlemen.
Click to expand...

Hi Ivecotrucker

It might be worth starting a new thread to put your question ... eg " Battery Power Monitoring"
It is a bit lost in here since the original thread title is about fridges.
I know the two things are related , I'm just thinking you may get more people reading it
and therefore more feedback ...

I would also like to hear other wildcampers experiences before rushing ( sort of ...ha ha !! )
to buy one

.... just an idea :idea:

OT
 
Be careful what your wife might wish for, Basildog. Some years ago we saw a fully plumbed in domestic clothes washing machine that the owner had installed in an otherwise bog standard white plastic motorhome.
 
Excellent thread!

As per the title, so......I have identified the chest freezer that would do the job, found the black box, that will change the freezer into a fridge (I guess it is a change of ranges to the thermostat), BUT, how do you convert the damn thing to run from 12 volt?
I have previously run a domestic 240 volt fridge from an inverter, but it killed the (rather expensive 600 watt) inverter after a few weeks as the start-up power needed was overloading it! And the inverter takes quite a bit of power, so almost negates the savings in the more efficient insulation and cost-saving in buying a 240 volt chest fridge!!!!
Buying a full sine-wave inverter makes the whole thing eye-wateringly expensive.........
Is there a solution?......Apart from going three-way?
 
windyjools said:
As per the title, so......I have identified the chest freezer that would do the job, found the black box, that will change the freezer into a fridge (I guess it is a change of ranges to the thermostat), BUT, how do you convert the damn thing to run from 12 volt?
I have previously run a domestic 240 volt fridge from an inverter, but it killed the (rather expensive 600 watt) inverter after a few weeks as the start-up power needed was overloading it! And the inverter takes quite a bit of power, so almost negates the savings in the more efficient insulation and cost-saving in buying a 240 volt chest fridge!!!!
Buying a full sine-wave inverter makes the whole thing eye-wateringly expensive.........
Is there a solution?......Apart from going three-way?
Click to expand...

Hi Windyjools

Thanks for the post !

But please tell exactly what the " blackbox" is that you are using.
The cheapest unit I have located in this country , that will do the job right ,is over a hundred quid !
You need something that will switch the mains power to the fridge on and off according to the set temperature
in other words , a thermostat with a built-in mains relay and an external probe to go inside the fridge / freezer.
It gets a little more complicated because you really need a thermostat unit with TWO set points .... it should turn the
mains ON when the temperature hits the UPPER set point , and turn it OFF when it reaches the lower point....
..... and ideally these points should be 3 or 4 degrees apart.
If it doesn't work this way you will find that the damn thing is CONSTANTLY going on and off which will hurt both
the inverter AND the compressor in the fridge / freezer.

Secondly , you DON'T convert it to run off 12 volts , you keep it working on 240volt AC and use a suitable inverter.
Personally , I would be looking for an inverter with a bit more clout than 600 watts because the instantaneous "start-up"
current draw of the compressor can be quite high .... as with any device with an electric motor in it.
Keep an eye on this thread because it is an ongoing project , with several Wildcamping members working on it.
I have recently found a small chest freezer for £149

HAIER BD103GAA Chest Freezer | Laskys.com

If my calculations are correct , this unit should use about 470 watts per day as a freezer, and WAY less than that
if it was converted to a fridge as mentioned in earlier postings on here , and using a mains thermostat as described above.

Gas fridges are OK up to a point , but they have their drawbacks .... especially in hot climates.
Anyway , thanks again for your post ...
... regards

Oldtech
 
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