caravan fridge on a boat

[ghostlymoron]

Having read on another thread about a gas fridge on a boat has made me wonder about a 'three way' caravan fridge on one. I understand that there are problems with them on gas if not level so that limits them but they can also run off 12v or mains. You can get one off eBay for > £100 so much cheaper than boat stuff. Also you could probably strip out the guts and use them in an icebox.
Has anyone done this?

 

[vyv_cox]

The 12 volt option is only available when the engine is running. The current draw is very large (it's a heater), 10 amps or more. The one in our motorhome cannot be run when stationary.

 

[PCUK]

I had an Electrolux on the boat for about 20 years. The 12 volt is unregulated so it freezes the entire fridge. Mains is good as is gas. However, they don't cool as well as a proper electric model. Mine was on a motor boat so being heeled for long periods in a yacht may have some adverse effect. Other than that and proper safe installation, no problems whatsoever.

 

[Gordonmc]

I had one on my last boat.
Only ran on 12v as while venting the gas may be easy in a caravan... just punch a hole in the side for the exhaust... its more complicated on a boat.
Downsides were the amount of room it took up in a 30 footer and the battery drain.
I gave it away eventually and settled for a cool box.

 

[rivonia]

We had one on our previous boat. No problems at all over a five year period. We had a seperate 12v deep freeze.

 

[prv]

Three-way fridges use a chemical absorption cycle rather than the more common compressor-expansion system. The power goes in in the form of heat, to boil one chemical and separate it out of another (can't quite recall the details). That's how they can run off gas - there have also been paraffin-driven versions.

The downside is that anything electrical that heats up will need a relatively large amount of power. A heat-powered fridge will probably need five to ten times as much power as a modern compressor one. OK off mains, but the 12v will spank the battery and the gas option is considered a safety risk.

The other issue is movement and heel angle. The absorption cycle involves carefully-shaped plumbing which the chemicals trickle through, and this needs to be level to within a few degrees to work. A sustained heel angle will definitely stop it working, and I imagine constant movement sloshing the stuff around won't be good for it either. Some fridges also have a problem (in gas or paraffin mode) where running them at an angle causes the burner flame (which always rises vertically) to miss the pipe it should be heating and burn other bits of the workings instead.

They were fitted in a few catamarans (no heeling), running off gas, in the 70s. But in general they're quite unsuitable for boats.

Pete

 

[V1701]

Could make your own compressor fridge (or look for a s/h Waeco compressor coolbox, though never seen one of these come up s/h, maybe they're that good people just hang on to them?) that will run eceonomically from 12v. Or if mostly for use when on shore power an inexpensive mini or tabletop fridge depending how much room you have might be the answer...

 

[ianj99]

Having read on another thread about a gas fridge on a boat has made me wonder about a 'three way' caravan fridge on one. I understand that there are problems with them on gas if not level so that limits them but they can also run off 12v or mains. You can get one off eBay for > £100 so much cheaper than boat stuff. Also you could probably strip out the guts and use them in an icebox.
Has anyone done this?

As a motorhome owner, we have the same problem as boat owners so unless you dared run it off gas, then the current requirement is too high for battery use only, even with a dedicated fridge battery. The compressor type are more efficient but not in the same price bracket sadly and still need 6 or 7 amps.

 

[rob2]

I used a 3-way fridge in a caravan and indeed with the van parked on a hill and unable to level it sufficiently it would not work on gas as the flame missed the capsule it is supposed to heat. The mains operation is great and is thermostatically controlled (as is the gas operation, I believe). It would be extremely difficult to get one to work at sea on gas as it would have to be gimballed and requires a reliable air floew from the base to the top as well as using this to extract the exhaust. The 12V heater is not thermostatically controlled as it is only intended to be used from the tow car's electrical system whilst the engine is running. I guess if one were to put a thermostat into the 12V circuit it would halve the consumption in the long term and whilst pitching and heeling would reduce the efficiency of the absorption circuit, it should still work.

Rob.

 

[ianj99]

I thought about using the compressor unit from an Argos dehumidifier and building it into a very well insulated top loading fridge. The unit was under £100 and is reasonably quiet when the fan that draws the air over the cooling fins has been disconnected. Still not practicable for running off batteries alone except for a short time via an invertor but should be a lot more efficient than the absorption fridge.

 

[ghostlymoron]

Sounds like I'll have to stick to plan A which is a cheap coolbox with extra insulation to keep milk, butter and bacon fresh. Probably only when engine running or sufficient sun for solar panel.

 

[fergie_mac66]

3 way

Sounds like I'll have to stick to plan A which is a cheap coolbox with extra insulation to keep milk, butter and bacon fresh. Probably only when engine running or sufficient sun for solar panel.

3ways do work I have one in 2Cats with no problems so long as you understand the principles and use common sense .The were fitted in many Cats and some monos (Sail) as standard in the 70's and 80's . Yachts are generally bigger now and compressors types became more accessible ,larger engines, more charging power . The pilot need really good air flow, if it gets that then CO levels dont cause a problem CO alarm is a must though . When we are using ours . Its only off in bad weather .but no thermostat so if its on too high the lettuce will freeze in the bottom ! We put it on mains in marinas.

In a mono long time at big angle of heel would be a problem but in general the pilot is fed up a steel tube and once warmed up it acts like a chimney and draws the heat up even at 15/20 degrees heel .

 

[VicMallows]

I have used a 3-way (top loading) fridge running mostly on gas on my Sadler29 for over 15 years. It is fine if it suits your style of cruising; and you are aware of the limitations and safety implications.

I am on a swinging mooring and very seldom visit anywhere with mains power available. I often moor or anchor in one place for around a week. From a power point of view a compressor based system was always in the past totally out of the question for my usage. Even now, with cheap solar, I couldn't realistically accommodate enough solar to run a compressor fridge in addition to my other requirements in a good UK summer. (Winter, when I also need the Eber as well as the laptop doesn't bear thinking about).

I therefore run on gas whenever at anchor. My previous fridge was a small Electrolux situated near the companionway with no external flue. CO was never measurable in the cabin. My current much larger box is installed in the fore-cabin and has a permanently installed flue venting on deck. Gas consumption is around 3kg/week. ( I use 7kg cylinders - you certainly would not want to be paying CampingGaz prices!).

As already said, they really do have to be reasonably level. No problem at all at anchor. If motoring in calm conditions I run the fridge on 240v via an inverter - works much better than using the 12v function and avoids the need for heavy cabling. Otherwise the fridge is off and stays cold enough for my typical passages. Of course, on the rare occasions I have mains available I use it!