Solar for refrigeration

[intreegingtraveller]

During a recent trip to France many people we met were complaining about the cost of gas bottles needed to run their fridges when touring 'off grid'. Some are risking both their health and the longevity of their fridge by charging it every few days at a campsite then allowing it to 'warm up' and hoping for the best while camping away from hookups rather than pay for gas bottles. Some manufacturers have even told their customers that they can't have a fridge which runs on solar power.
We installed a compressor fridge in our motorhome which runs solely on solar via our leisure batteries - 10years ago! The compressor system also has the benefit of operating at an angle of up to 30 degrees which obviates the need for the levellers simply to make sure the fridge will work.
In these days of heightened environmental awareness wouldn't it be better for motorhome manufacturers to provide us with systems designed to cut our use of fossil fuels rather than one which supports the manufacture of gas bottles?

 

[mom]

G'day!
Our fridge is 3-way (240, 12, gas), but the 12 volt is only available when driving and doesn't cool the fridge very well. I'm interested in your 12 volt fridge... does it cool as well as 240 or gas?
Regards, mom

 

[Baloo]

Cant believe people wont pay for gas bottles! They pay thousands of pounds for a motorhome and then wont pay £20 for gas! Fridges dont use that much gas anyway.

Our three way fridge doesn't freeze very well when we are driving and we lost a whole freezer full of food on a long drive. This seems to be a common fault.

 

[mom]

Ours actually uses a fair bit of gas, especially during the summer (I know, goes without saying ;-) )

But I like the idea of running entirely from the sun, I must admit! Not sure how effective solar would be in the UK, even in the peak of summer?!

 

[intreegingtraveller]

Sorry for the delayed response, we've been away.
We only have a small 'van so the capacity of our fridge is only 56 litres and doesn't have a freezer compartment as such- just a cubby hole suitable for storing an occasional icecream. We have run it on one 75w solar panel, flat mounted on the roof which charges the leisure batteries which in turn keep the fridge working. In Europe it has always been set on the lowest possible setting otherwise things become too cold - in America I had to turn it up a little when the outside temperature reached 40 degrees C. Even on overcast days there is enough 'ooomph' in the suns' rays to keep things charging. CakTanks is a good source of info. Waeco produce compressor fridges.

 

[UKMotorhomes]

I don't know what's up with modern fridges, lots of people complain that they don't work well on 12v. The fridge in our old motorhome, built in 1991, worked brilliantly on the 12v when driving, sometimes it was too cold. If they could do it then why not now?
On the subject of 12v compressor fridges, our current van has the Waeco MDC-110 compressor fridge and I calculate that it uses between 40 and 45Ah per day. We have 160W of solar panels and don't suffer power problems during the summer months. Winter is a different matter however, we have Webasto diesel fired heating, with that and the fridge we can only last a couple of days or so, even with our 400Ah battery capacity.
You can get compressor fridges with lower power requirements (Diamond Dave Newell fitted one in his van), the top-opening ones will be better too.
Andy

 

[SteTomo]

If you're worried about the small amount of gas in a gas bottle, fit a fixed tank! Our 60 litre fixed tank is hung between the chassis members so is high up and holds as much LPG as just over 4 12 KG cylinders. Plus I can top it up when I top up the diesel and it only costs £25.00, or less to fill it from empty. No lugging bottles, no running out unexpectedly, no hassle.

 

[UKMotorhomes]

I agree that fixed tanks are a great idea, we have one. However a 60 litre tank, allowing for an 80% fill, will hold around 48 litres of LPG. 1 litre of LPG weighs around 0.5kg so your capacity is about 24kg, the equivalent of 2 12kg bottles. If I've got my sums right...
Andy

 

[twooks]

get a compressor fridge - whether solar or 12volt
far more efficient than the 3 way type - AND you don't have unsightly grill covers to spoil the line and look of your van
AND you can leave it on on ferries

 

[SteTomo]

Sorry Andy, sums woz never my strong point at skool!

 

[UKMotorhomes]

@twooks Yes, compressor fridges are great, we have one, but you have to take into account the additional battery drain. Ours uses around 40Ah per day. Fine if you are on mains hookup or have enough solar panels to cope with it.
Andy
Hmm... why is there no 'quote' facility on this forum?

 

[TonyJones]

I don't know what's up with modern fridges, lots of people complain that they don't work well on 12v.

Here's the "quote" facility Andy. It's there at the bottom, near the "Reply" one.
I wonder whether the problem is the installation of fridges nowadays? The back of the fridge needs to be completely sealed off from the living area, and vented top and bottom to the outside world, and I've certainly seen vans where that wasn't done - or not done properly. The fridge would then be less efficient on all fuel, and since 12v is often the least efficient of the three anyway, that's where the difference would show up worst.

 

[TonyJones]

get a compressor fridge - whether solar or 12volt
far more efficient than the 3 way type - AND you don't have unsightly grill covers to spoil the line and look of your van
AND you can leave it on on ferries

Hi "twooks" - are you aka Jackie, formerly known to haunt another MH mag forum?

 

[UKMotorhomes]

I don't know what's up with modern fridges, lots of people complain that they don't work well on 12v.

Here's the "quote" facility Andy. It's there at the bottom, near the "Reply" one.

Ah, but it wasn't there when I posted that! It's only just been 'fixed'

I wonder whether the problem is the installation of fridges nowadays? The back of the fridge needs to be completely sealed off from the living area, and vented top and bottom to the outside world, and I've certainly seen vans where that wasn't done - or not done properly. The fridge would then be less efficient on all fuel, and since 12v is often the least efficient of the three anyway, that's where the difference would show up worst.

I don't know about that, the old fridge I was talking about wasn't sealed off from the living area at all!
Andy (also on the 'other' magazine forum!)

 

[CapableClive]

Technically compressor fridges are more efficient than absorbtion type fridges that can run on gas. BUT all the power has to come from the 12 volt supply. If you live in the sun and have LOTS of solar real estate then it will work for you. A cheaper option is to have a massive bank of batteries that have enough storage to last the duration of your wild experience. BUT they are heavy. The gas fridge takes either zero or little from the 12 volt supply and is also perfectly quiet (unlike the compressor fridge). If you can acomodate a sizeable bulk LPG tank then the gas costs is much reduced compared to bottled gas and the amount of energy is a killo of gas is many times more than can be stored in a kilo of battery.
Hookup is cheapest!

CC.