Compressor fridges

[Qwin]

I'm going for a small compressor fridge in my current build, had a 3 way absorption in the old Motorhome.
Planning a 200Ah battery and at least 370w of solar, should be fine for me, no other items with a major currant draw.
While researching, I read some comparative reviews which said, modern top brands, Dometic etc are very efficient, but a similar sized brand X, could use up to three times the power. So they vary in power usage a lot, model to model.

 

[Raul]

I only have experience with Dometic CRX fridge, and a copy of mobicool top load freezer. Both are on similar consumption 25-30Ah at 12.8v, per day.
If anything, the freezer is a tad more efficient, probably being top load and less frequent openings.

 

[G-RMPS]

Not just UK-build vans with silly batteries. Our Malibu van came with one 85ah battery to power the compressor fridge and everything else.

Now upgraded with 185w solar and 280a lithium. That all fits fine in a PVC. We think that will work for our usage, though extra solar would always be a "free" benefit.

 

[Ian_H]

Not just UK-build vans with silly batteries. Our Malibu van came with one 85ah battery to power the compressor fridge and everything else.

Now upgraded with 185w solar and 280a lithium. That all fits fine in a PVC. We think that will work for our usage, though extra solar would always be a "free" benefit.

And our Globecar Summit Shine had a 95Ah battery and a 100 litre compressor fridge that uses about 45Ah/24hours ie the whole battery capacity in one day! We were aware of the issue before buying and now have 250W solar and 230Ah lithium. No problem 4 days offgrid with no solar input

 

[Barriesimpson]

?? Never heard of that before. Ours is left on site in the South of France for weeks on end (and used daily) and all the frozen items remain frozen, and the fridge items really cold (35+ degree heat). Although that is on the EHU, will that be different on gas??

No, it will be the same.

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[Barriesimpson]

Our 3 way still works in 39°c ambient.

Ours too.

 

[Barriesimpson]

Well that's a bizarre comment....you are totally ignoring the one main benefit of a 3 way fridge.... the very fact it can use multiple fuel sources.. having lived on a boat for 5 yrs with a small compressor fridge and now in our motorhome with the 3 way and the ability to switch fuel sources.... mains/gas/12v/ even solar when its producing enough...i greatly appreciate that over constantly worrying how much power i have in my batteries to power the compressor.... we fulltime and despite its occasional foibles I'll take my Dometic 3 way flexibility any day..

I agree with this. I think the 3 way fridge/freezer is a brilliant invention, one I was not aware of until beginning the motorhome life, and it works very well in all circumstances.

 

[Garry - June]

I agree with this. I think the 3 way fridge/freezer is a brilliant invention, one I was not aware of until beginning the motorhome life, and it works very well in all circumstances.

Funny how things change eh ...we swapped out the 3 way for a compressor model which has run 24/7 since we installed it two years ago....along with our LifePo batteries by far the best upgrade we have made in our van.... i would never go back to a 3 way now.

 

[barryd]

I can see the appeal of going (Almost) gasless. Diesel heating and compressor fridge but our style of camping is different to most. We can and do often park up for weeks on end without moving the van, mainly because we use the scooter for touring about. Therefore I would need a solution that works indefinitely without moving the van between April and the end of October. We now have 240ah of lead acid and 240w of solar. For our current set up its fantastic. Ill never run out of power, not even close, even without moving the van but I have no idea what I would need to upgrade to if at some stage we were to change and go gasless.

Ill not do it until the Fridge or the Truma system gives up the ghost though. They work perfectly right now, I have no power issues and I Can always find gas. I think maybe for us if its not broken don't fix it (until it breaks)

 

[Jim]

I've changed my mind somewhat since I last posted in this thread. Probably has a lot to do with lithium batteries. I carry 600 amp hours, my three-way fridge is playing up, and I'm investigating swapping out my 3-way fridge for a compressor model quite soon.

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[EuroTrotters]

We’ve now got used to the higher noise they make. Don’t even notice it now.
Often spend 3 days off grid without any issues.

Some of them can easily be quietened down

 

[Wildbill]

We I have a full size 12 v compressor fridge in the van I have been testing on solar and 280 ah lead acid batteries with 420 w of solar been going five days now with no issues
WB

 

[ian27]

I agree with this. I think the 3 way fridge/freezer is a brilliant invention, one I was not aware of until beginning the motorhome life, and it works very well in all circumstances.

I'll challenge that and say "for you".

my experience over 10 years caravanning is a constant battle to keep food cold in warm climates with a 3 way. I am far from the only one, there are zillions of threads on hundreds of t'internet forums about "3 way fridge not cold enough".

yes, you might have got a setup that works. thats great, good for you, not dissing it, enjoy your cold beers

but the only way to have a setup that is "guaranteed to be cold, no matter what standard of insulation / ventilation forced or otherwise / vehicle design / fuels source / ambient temp" - is to use a compressor. 3 way works for some, in some circumstances and implementations, it doesn't work for all in all circumstances and all implementations.

yes, the compressor needs a decent 12v supply and will only work if that is available. But that isn't difficult to implement in this day and age.

The compressor fridge is also intrinsically more efficient than the 3way in terms of energy input required for the same amount of cooling. The physics of this is clear and well documented. Real RV fridge implementations (same size unit) yield an efficiency gain of factor of 5 at least on changing from 3way to compressor. I've measured this - based on electrical of course, not possible to do with gas. The fact that with a 3 way you can "work around" this by getting energy from a very very dense source (gas) or from an effectively unlimited less dense source (EHU) isn't the point.
If you keep all things the same i.e. the same source at the same density (battery stored electricity) you'll go through it way quicker with a 3 way. So if you can achieve a suitable stored electrical energy density and capacity in your vehicle, you will have a guarantee of cold food and greater efficiency of usage of that energy , with a compressor.
in practice, lithium is what makes the difference. with out that its hard work to achieve the necessary density and capacity.

 

[Jonno1103]

The eat gas because they can. In winter with little solar and nothing else I'm glad of that. They can be easily serviced anywhere in the world at the side of the road and I've never had a problem in very warm weather. People normally have their gas too high when its really hot and that is often the most innefficient setting.

I understand the benefits of compressor fridges especialy with a roof fulll of solar and a locker full of batteries. But supplying them from new with a 75AH battery is pretty dumb in my opinion.

Yep, Auto Trail now fit compressor fridges in the Excel & F Line coupled to 200w of solar but only 1 standard 70AH lithium. You need to spend a further £549 if you want a 2nd battery. This'll still only give you a combined 140Ah.

 

[Jonno1103]

?? Never heard of that before. Ours is left on site in the South of France for weeks on end (and used daily) and all the frozen items remain frozen, and the fridge items really cold (35+ degree heat). Although that is on the EHU, will that be different on gas??

Absorption fridges only really work properly upto around 25c, they struggle a lot beyond that especially if they're full and the fins have food in front of them stopping air from circulating. They're only rated 2 star at best. Many owners fit aftermarket fans and others fully remove the fridge vents.

Their performance depends on many things most of us don't even realise, for example, which way the door opens - if it opens to a large warm lounge it'll struggle to cool the warmer ambient air rushing in as the cool air escapes. Another? Aluminium sheathed motorhomes radiate and absorb a lot more heat which slows the vans cooling during the hours of darkness.

On the flipside of that, habitation air con chilling the interior will help them a lot. Even a standard fan on a worktop will offer an improvement in performance.

I tried an experiment with our hab air con in 32c and the fridge on gas. I managed to get the interior temp down to 19c and gas consumption dropped by just over 18%.

Compressor fridges are regaining popularity due to the advances in battery technology, having a more consistant temperature range, being lighter and also allowing converters & coachbuilders to lower the gas bottle capacity which means at least a 28kg improvement in payload. As almost 80% of motorhomes are now down plated to 3500kg the latter is all important.

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[pilchard]

PVC’s with little roof and battery space, coupled with a compresser fridge, is a recipe for warm beer. Three ways rule

This is exactly my fear, and am glad I found this thread. We are hoping to downsize from out current motorhome... with 3-way fridge... to PVC with a compressor fridge. We do most of our camping off- grid... either in random unlicensed layovers or CLs with just water and waste.
The consumption of compressor fridges IS a concern, and you are right, roof space on PVCs is limited and battery space is miniscule.
If.... if... it was possible to install approx 200 watts of solar, would it be practical to be always off-grid on the standard small single battery as installed by the converter?

 

[Ian_H]

This is exactly my fear, and am glad I found this thread. We are hoping to downsize from out current motorhome... with 3-way fridge... to PVC with a compressor fridge. We do most of our camping off- grid... either in random unlicensed layovers or CLs with just water and waste.
The consumption of compressor fridges IS a concern, and you are right, roof space on PVCs is limited and battery space is miniscule.
If.... if... it was possible to install approx 200 watts of solar, would it be practical to be always off-grid on the standard small single battery as installed by the converter?

No. Many cloudy days you will not get anything useful from your panels (however big they are). A lead acid battery of 100Ah (50Ah useable) may last one day.

 

[ian27]

This is exactly my fear, and am glad I found this thread. We are hoping to downsize from out current motorhome... with 3-way fridge... to PVC with a compressor fridge. We do most of our camping off- grid... either in random unlicensed layovers or CLs with just water and waste.
The consumption of compressor fridges IS a concern, and you are right, roof space on PVCs is limited and battery space is miniscule.
If.... if... it was possible to install approx 200 watts of solar, would it be practical to be always off-grid on the standard small single battery as installed by the converter?

there are plenty threads on here and other fora about fitting significantly more than 200W of solar on a PVC. Go to lithium and your electrical storage density goes up substantially. you can also lose the gas completely (if you move to electric cooking and diesel heating) or substantially reduce its usage.

my attempt at questions to ask and where that steers:

able to go to hot countries with no "is fridge cold enough " stress, ever -> compressor
cooler countries only->3way
pure energy consumption efficiency->compressor
desire to go gas free-> compressor
plenty of solar and/or drive around a lot -> compressor
accept some level of noise -> compressor
(not so clear cut) lithium + larger battery-> compressor ....grey area..... lead acid+ smaller battery capacity-> 3way
large gas storage capacity (and no desire to get rid or reduce it) -> 3way
not much solar, not moving around much , no ehu -> 3way
completely silent -> 3way

on EHU all the time-> either. Climate the next most important question.

 

[pilchard]

No. Many cloudy days you will not get anything useful from your panels (however big they are). A lead acid battery of 100Ah (50Ah useable) may last one day.

So presumably the only solution is to replace that small 85ah battery that lives under the seat with a good capacity Lithium one. PVCs, as well have having compression fridges, always have blown air. You add the consumption of the fridge, the blown air, charging iPad and phones, lighting etc... all possibly in dreck winter conditions... and that's a lot of drain with very little input. Would a Lithium be the easy solution?

 

[ian27]

So presumably the only solution is to replace that small 85ah battery that lives under the seat with a good capacity Lithium one. PVCs, as well have having compression fridges, always have blown air. You add the consumption of the fridge, the blown air, charging iPad and phones, lighting etc... all possibly in dreck winter conditions... and that's a lot of drain with very little input. Would a Lithium be the easy solution?

you can fit 300ah of lithium under a seat these days, so yes. when you say blown air what you mean? heating? with what as the heat source?

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[Ian_H]

So presumably the only solution is to replace that small 85ah battery that lives under the seat with a good capacity Lithium one. PVCs, as well have having compression fridges, always have blown air. You add the consumption of the fridge, the blown air, charging iPad and phones, lighting etc... all possibly in dreck winter conditions... and that's a lot of drain with very little input. Would a Lithium be the easy solution?

Everyone will have their own opinion but for us an underseat 230Ah lithium, 250W solar and the original 25A b2b works. We also replaced the original mains charger with a 30A victron. It doesn't get used a lot, but the battery is getting the proper charge cycle when required. 20A would have been plenty. In summer we can offgrid indefinately, in winter we are fine for our short breaks of 2-3 nights. Our van is 5.4m long, more space in 6m and bigger!

 

[daveandsan]

So presumably the only solution is to replace that small 85ah battery that lives under the seat with a good capacity Lithium one. PVCs, as well have having compression fridges, always have blown air. You add the consumption of the fridge, the blown air, charging iPad and phones, lighting etc... all possibly in dreck winter conditions... and that's a lot of drain with very little input. Would a Lithium be the easy solution?

Lithium would be the way to go, don’t forget you can fit the lithium on its side if you are struggling for room.

 

[KiwiKev]

I have had 12v compressor fridges in my vans since my first self build van in 1996. Any (used) vans I acquired over subsequent years, 3 way fridges were immediately swapped out for compressor fridges. 1st van had gas blown air heating, subsequent vans had diesel heating. Always made sure I had adequate battery power, 1st van in 1996 had 2x105ah 'Trojan' golf cart batteries, subsequent vans, capacity went up from there, now have 300ah Lithium, 160W roof + 210W folding portable solar. Never been bothered by fridge noise or run out of battery power.
Other people have mentioned the advantages of compressor fridges. Major reason (for me) for going compressor fridge, 3 way fridges wouldn't work when off level (might be better with latest). Our 1st van had to be parked on our drive on an incline. Long ferry trips (Portsmouth- Bilbao), gas fridges must be turned off.
I have a theory that gas 3 way fridges are great midge (mosquito?) attractors. Commercial midge traps burn LPG, create Co2 and heat to attract midges, gas fridges do the same. Have read reports of midges coming in through the fridge vents in Scotland.

 

[Barriesimpson]

I'll challenge that and say "for you".

my experience over 10 years caravanning is a constant battle to keep food cold in warm climates with a 3 way. I am far from the only one, there are zillions of threads on hundreds of t'internet forums about "3 way fridge not cold enough".

yes, you might have got a setup that works. thats great, good for you, not dissing it, enjoy your cold beers

As I said, it works perfectly.

but the only way to have a setup that is "guaranteed to be cold, no matter what standard of insulation / ventilation forced or otherwise / vehicle design / fuels source / ambient temp" - is to use a compressor.

Or set up the 3 way properly.

3 way works for some, in some circumstances and implementations, it doesn't work for all in all circumstances and all implementations.

If it's properly installed and setup, it'll work for everyone.

yes, the compressor needs a decent 12v supply and will only work if that is available. But that isn't difficult to implement in this day and age.

Many people may not be able to afford it though.

The fact that with a 3 way you can "work around" this by getting energy from a very very dense source (gas) or from an effectively unlimited less dense source (EHU) isn't the point.

This is exactly the point.

If you keep all things the same i.e. the same source at the same density (battery stored electricity) you'll go through it way quicker with a 3 way.

It doesn't matter, gas is cheap and electricity (if you are already paying it) is constant.

So if you can achieve a suitable stored electrical energy density and capacity in your vehicle, you will have a guarantee of cold food and greater efficiency of usage of that energy , with a compressor.
in practice, lithium is what makes the difference. with out that its hard work to achieve the necessary density and capacity.

You complicate the issues too far. Very few people will understand density and capacity of energy sources. They just want cold beer, and with a 3 way fridge you have it.

 

[carolyn]

So presumably the only solution is to replace that small 85ah battery that lives under the seat with a good capacity Lithium one. PVCs, as well have having compression fridges, always have blown air. You add the consumption of the fridge, the blown air, charging iPad and phones, lighting etc... all possibly in dreck winter conditions... and that's a lot of drain with very little input. Would a Lithium be the easy solution?

We have a PVC and have diesel heating. It’s a year old. We paid extra for that option. We have a compressor fridge. A 240Ah lithium battery and 320W of solar. We have an underslung lpg tank 20 litres but that’s just for the oven and hob. I reckon we’d be OK in the UK spring to Autumn unless the weather was very bad without moving or if we were far North of Scotland.

We’ve just been away for 7 weeks, 4 of which were in Iceland. It might be light all night but the weather was not sunny so we didn’t get many Ah overnight . Probably between 11pm and 7am there was just enough for the fridge bearing in mind it was cold (4 degrees) , sometimes the heating came on!

I did use the Remoska and the single induction plate most days as I wanted to try things. We moved most days but if we stayed 2 days doing this the battery would be down to 50-55% if we’d had no sun. It was brighter than an English Autumn though and later of course. A grey drizzly day and we’d get 3-400Ah .

Obviously we could use the cooker and gas kettle to extend things a lot but didn’t need to as we were moving so often.

If we wanted to Offgrid in winter we’d need another lithium battery to avoid having to keep moving. May consider that in the future but so far we haven’t done winter rallies. We’d go to Offgrid Power Solutions if we do want one though.

It has been interesting, saved us €15 plus per night in hookup fees!

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[ian27]

As I said, it works perfectly.

Or set up the 3 way properly.

If it's properly installed and setup, it'll work for everyone.

for you. in some vehicles you can't, without rebuilding half the damn vehicle.

please, I'm not trying to be grumpy - I only challenge your assertion that "3way works well in all circumstances" without a qualifier.
If you accept that it needs to be qualified with "for me(you) and for other people with well implemented setups" then we agree


also if you want something that is 100% certain to work (by which I mean maintain cold in all climates)

• 3way is proven less likely to be able to maintain sufficient cold in hot climates (physics of how it works). Not impossible - but a lot less likely.

two of the other points are for debate and we can agree to disagree but from my side of the fence

• gas shouldn't be cheap.
• people need to understand things like energy density, capacity, source, if they are designing or choosing a mobile solution they drive around with.

 

[ian27]

We’ve just been away for 7 weeks, 4 of which were in Iceland. It might be light all night but the weather was not sunny so we didn’t get many Ah overnight .

digression from the thread, how did you get to Iceland with the motorhome? would love to go there but seems you have to go to norway or denmark first?

 

[Barriesimpson]

for you. in some vehicles you can't, without rebuilding half the damn vehicle.

That may well be the case. I bought my motorhome new with all the installations done, including the 3 way Thetford fridge of the latest available (I assume).

please, I'm not trying to be grumpy - I only challenge your assertion that "3way works well in all circumstances" without a qualifier.
If you accept that it needs to be qualified with "for me(you) and for other people with well implemented setups" then we agree

Well if it works for me it should work for everyone, I am not a sorcerer or magician.

also if you want something that is 100% certain to work (by which I mean maintain cold in all climates)

• 3way is proven less likely to be able to maintain sufficient cold in hot climates (physics of how it works). Not impossible - but a lot less likely.

That may well be so, however in 40º which we do see often in the Canaries, it still works flawlessly.

two of the other points are for debate and we can agree to disagree but from my side of the fence

• gas shouldn't be cheap.

Why not?

• people need to understand things like energy density, capacity, source, if they are designing or choosing a mobile solution they drive around with.

But we all know that they don't .

I'm not being grumpy either, but I do feel that there is too much negative hype on the 3 way fridges that do do exactly what it says on the tin (box in this case). Compressor fridges like we have at home are noisy and use an awful lot of electricity that many people just do not have in their vans. But of course, each to their own.

 

[pilchard]

you can fit 300ah of lithium under a seat these days, so yes. when you say blown air what you mean? heating? with what as the heat source?

We are talking off-grid so the blown-air heating will be heated by gas but blown by 12volt.

 

[carolyn]

digression from the thread, how did you get to Iceland with the motorhome? would love to go there but seems you have to go to norway or denmark first?

Ferry from Hirtshals Denmark via the Faroe Isles, Smyril lines.

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