240v Fridge

[kencoley]

This may seem mad but I am thinking of replacing my fridge (rusty and done) with a 240V fridge with an inverter! I know this may be daft but a new 12v fridge is nearly 600 quid and the 240 volt have anyway, they are 99quid new, I rarely run the fridge without the engine running anyway. am I mad or does this make sense?? /forums/images/graemlins/smile.gif

 

[twisterkai]

The insulation on domestic fridges leaves rather a lot to be desired, so you can't really expect them to maintain beer/wine etc at an acceptable temperature when the engine isn't running.

Instead of a fridge, what about one of those cool boxes with a chiller plate? Fairly cheap and you can plug 'em in the car on the way down to the boat.

 

[kencoley]

The trouble with cool box is they are top loading and the space is for a front door type, although useful if you have to drive to your boat, I don't have to drive, thankfully.

I still think that a 240v fridge is not so bad, you can get generators for little money now, even diesel, still chaper than 12 volt fridges and you have the advantage of 240 for other appliances?

 

[Talbot]

Caravan fridges might be the answer. These are multifuel - lpg/12vdc/240vac. I use mine on lpg cause I have a cat, because they must be upright for use of that fuel. 12v is very power hungry (abt 8 amps) and on 240v they have a thermostat. You could operate at sea on 240/12v and on lpg when on harbour, and then would not need to annoy neighbours by running a generator all day.

 

[PCUK]

I've always used a gas/12 volt/240 volt fridge. I use it on the gas while anchored and while running. It seems happy with normal rolling but if you were close hauled and heeled for a long time then as Talbot says, it wouldn't like it. We used to use the 12 volt while running but as this is not thermostatically controlled everything just freezes. We found we could play rounders with a cucumber and tomato!
Personally for economy I think you have a good idea using a cheap mains fridge and inverter.

 

[VicMallows]

Agree with Talbot and Pershila.

Also use a 12v/240v/LPG and works absolutely fine. Only problem is it must be level (any fuel) . If you dry out (I'm a bilge keeler, and do it often) use a small spirit level and adjust fridge when settled etc.

(no doubt the anti-gas brigade will have something to say)

Vic

 

[William_H]

The option of 240v domestic fridge is very persuasive at the price. Certainly 12v or 12/gas are vastly more expensive and less efficient.
Cool boxes top loading are designed to keep the cold for a long period without powering up so certainly are more efficient than the doemestic fridge but would be no contest if you have shore power available. (ie domestic best deal on cost)
I have been told that the induction motor on 240v fridges don't like square wave or modified square wave as provided by cheaper inverters. I believe the sine wave is best if not essential. (this goes for generators, the cheaper ones providing an inverter type output wheras the older or expensive style have an AC alternator which produces pure sine wave. A sure sign is if the engine must run at exactly 1500RPM or 3000RPM that is a good alternator.
{1800 or 3600 for US}.
So I strongly suggest you take your fridge and an ampmeter to the shop where you buy your inverter. Run the inverter on your car battery measure the amps required for start and run of the fridge and check the sealed unit for excessive heat after a short run before buying. (check to see how hot it gets at home on mains first) if all is ok then go for it.
good luck olewill

 

[joeh]

have u consider a portable ice maker ? runs on AC but limits batt/inverter usage . available westmarine.

 

[kandoma]

check out first the inverter with your fridge at home. Some low power inverters are unable to start the compressor reliable. Otherwise, why not ? Power consumption is much higher then a 12 volt fridge.

Peter

 

[TrueBlue]

Some observations to enlighten or more probably confuse.

(1) Gas/ 240V / 12V fridges (I'm surprised that you can still buy them) use the power to heat the coolant (I won't even try to explain) and are exceedingly inefficient. When we hired boats many years ago we noticed that the gas fridges just were not up to keeping anything cool, let alone making ice for our G&T's. Hire boat operators fitted them because they were cheap and reliable.

(2). I know of one time-share type company who actually fit domestic fridges and power them from an inverter. They wouldn't do that if they were either power hungry or unreliable or if the needed an expensive sine wave inverter.

(3). I understand / infer that the Danfoss 12 or 24V units fitted by many manufacturers are actually 240V AC units with a built in inverter.

(4). I looked at an old fridge compressor unit some time ago and it was rated at 70W.

(5). Modern fridges of the "A" class are made to be efficient and if you are going to have a mains units then got for one of these.

(6). At least one of the "marine" fridge manufacturers uses cases made by LEC.

(7). The main differences between domestic and marine types are:-
Better / more robust fittings
More / better insulation
Some tweaking of the compressor control system to have a wider spread
of temperatures between the On and Off condition.

(8) You pay much more for a marine / caravan unit because they are made
in small quantities and because the market will bear a higher price

Very IMHO I don't think you'll find much difference in performance / consumption between a good domestic unit and a marine one.

If you have 24V then a chandlery in the Reading are is selling 3cu.ft units for £99 on eBay. They are basic units but look reasonably solid. He hasn't got many left....

When my fridge freezer goes belly up I'll almost certainly go for a 240V unit.

 

[Guest]

There are plenty of caravan breakers about and good condition multi-fuel / 12V fridges available .....

I have one in my holiday park van and it works well ....

I am always thinking about a s/hand one myself for the boat .... but never seem to get around to it ....

 

[summerwind]

Re: Some observations to enlighten or more probably confuse.

[ QUOTE ]
(1) Gas/ 240V / 12V fridges (I'm surprised that you can still buy them) use the power to heat the coolant (I won't even try to explain) and are exceedingly inefficient. ............. gas fridges just were not up to keeping anything cool, let alone making ice for our G&T's

[/ QUOTE ]

Hmmm! Can't agree I'm afraid. I have had one of these running constantly for the last five years on all three methods of power at various times, depending on what I was doing.

My fridge makes plenty of ice, although I can't stand G&T. In fact, if I'm not careful about the settings, my milk etc will be ice.

I bought it for the versatility and the concern about 12v power drain on dull, windless days on a mooring. The fact that it was a considerable bit cheaper than marine models helped.

Whilst I'm attracted to the idea of a 240v fridge + inverter as opposed to a marine style box, the power drain still concerns me and I still believe the multi- power option to be the best. Expanded foam around the installation will help with insulation, whatever model is installed.

 

[VicMallows]

Re: Some observations to enlighten or more probably confuse.

Agree with summerwind. Have had a gas/12v/240v (top loader electrolux) since 1978 and couldn't live without it. It did extensive service camping, including Greece in hight of summer, before taking up residence on the boat. I use gas at anchor; 12v underengine, and 240v if (free) electricity available. Only trouble is it must be reasonable level to work. When dried out on the mooring etc I just adjust it with a small spirit level.

Vic

 

[Guest]

Agree .....

I have to be careful where I put stuff in my 12v/240v/gas fridge .... too near the ice-box and I get frozen products !!

Only complaint I have is that the ice-box is too small !! Two ice trays and its full.

IF I was to replace the above with a 240v mains fridge - which has crossed my mind ... then I would certainly put the 12v job on the boat ....

 

[DaveS]

In general I go along with your comments, but I don't quite follow your point about being able to assume good waveform if the stated speed is an "exact" number. Granted, this will ensure accurate frequency (50Hz if 1500 or 3000 rpm, 60Hz if 1800 or 3600 rpm) but I don't see that this tells us anything about what sort of waveform, sine or otherwise, is produced. Am I missing something?

 

[Guest]

Mmmmmmmmm rpm ....

Think cycles and waves have got mixed up there .....

 

[mark_turner]

One thing I would say:

There are two types of fridge - 'absorption' and 'compressor' type.

The former works by heating up a liquid and causing evaporation. The evaporation is used to generate the 'coolth'. (the ones that have lpg or 12V/lpg/240VAC will I think be this type)

The latter compresses a gas to make it hot he gas is then cooled and causing it to condense to liquid. Passing it through an expansion valve again causes the refrigerant to expand and evaporate to a gas providing the 'coolth'. (the domestic fridge running on 240VAC will be this type)

The latter are more efficient but result in a poor power factor which may be a problem for an inverter as its output will be reduced by this (it needs more current for the same power). Worth checking the details of the inverter maybe?