3 way fridge

[Nb Unity]

Weve just had ours repaired to work it off 12v, as weve got 4 leisure batteries we should have ample power to run the fridge on , on using 12v only do we need the exhaust pipe ?

Thanks

[Chris-B]

Weve just had ours repaired to work it off 12v, as weve got 4 leisure batteries we should have ample power to run the fridge on , on using 12v only do we need the exhaust pipe ?

Thanks

Is this the old "electrolux" type fridge ?

RM212 ?

 

If so .try NOT to run it on 12v as it will eat battery's alive.better to run this type on gas

 

Chris

[AlanH]

Weve just had ours repaired to work it off 12v, as weve got 4 leisure batteries we should have ample power to run the fridge on , on using 12v only do we need the exhaust pipe ?

Thanks

Most 3 way fridges eat up amps at an alarming rate when used on 12v.

 

I would think that, if it is connected to the gas you will still need the flue.

Edited July 19, 2010 by AlanH

[Speedwheel]

It will use 7-10 amp running from 12volt - compared to a dedicated 12volt only which will used 1.5-2.0 amps.

 

As others have said, best to use it on gas.

[Bill]

It will use 7-10 amp running from 12volt - compared to a dedicated 12volt only which will used 1.5-2.0 amps.

 

As others have said, best to use it on gas.

 

Also there is no thermostat on the 12v side, so it will never switch off and draw 7-10 amps all the time.

[Radiomariner]

These fridges designed for caravan's are primarly mains or gas. The 12Volt option allows you to keep the fridge going when the caravan is under tow. They will use up more Ampere Hours than just about anything else on your boat.

If you use the gas it must be fitted as the manufacturers advise. (No modifications whatever) It is not recommended to have a gas fridge on a petrol powered boat.

If you leave it as it is, without flue or manufacturers flue fittings make sure that the gas line to the fridge is properly capped.

[Radio-Ga-Ga]

They are intended for motorhomes/caravans while traveling and supported by the alternator, and switched to mains or gas on site, as said it will run your batteries flat in no time. If cost is a priority a household mains fridge and inverter will use far less power.

 

ooops cross posted with the above!

Edited July 19, 2010 by Radio-Ga-Ga

[billh]

Most 3 way fridges eat up amps at an alarming rate when used on 12v.

 

I would think that, if it is connected to the gas you will still need the flue.

 

8 amps when I last measured one, feeds a heater, on 95% of the time .Not good.

I recently installed a LEC 12v fridge- full size , compressor type, 3A draw but only now & again if you keep the door shut. excellent.I think these are pretty standard in hire boats. There is another type, the make I forget, which is a 240v ac compressor type with its own built in inverter- current draw is 3.5A @12v- pretty good I would say.Both these mentioned are not latest tech,so I suppose the newest models are even better than these.A lot less messing around than gas.

Bill

[Liam]

The previous owner of the boat ran it on gas, but we've had problems getting it to stay lit, which is why my parents (the OP) wanted to run it on 12v. We tried the usual thing of cleaning the jets and leaving it upside down for a week and stuff.

 

It's killed their batteries twice before now (4 x 135ah and fully charged) which is why they've sent it off to be looked at - the bloke said it was a dodgy switch but it's going to carry on eating your batteries by the sounds of it. Best to get a new "exhaust" for it and get it back on gas as there's no 12v wiring for it anyway.

[Speedwheel]

make sure that the gas line to the fridge is properly capped.

 

Just not with a blanking nut!

Edited July 19, 2010 by Speedwheel

[Nb Unity]

Thankyou all x

[Liam]

I take it that all 3 way fridges suffer with the 12v side by caning the batteries then, and its just not this older model? Would a newer 12/240/Gas fridge be more battery friendly or would you be better sticking with Gas? I ask because if thats the case its probably going to end up with me looking at other solutions as my parents aren't that keen on gas. They do have it on their boat and use it for cooking, but leaving a fridge on 24/7 whilst they are out on the boat doesn't really make them comfortable.

 

Thanks all

[Speedwheel]

All three way fridges will be heavy on 12volt - even the new ones.

 

The purely 12v ones work with a compressor but the gas ones use a different method. When they run off 12volt they are effectively running a heater to replace the gas flame.

 

This explains it quite well.

 

How a gas fridge works - the heat applied to the generator is where the power is used when running on 12volt.

 

http://home.howstuffworks.com/refrigerator5.htm

 

How a compressor fridge works.

 

http://home.howstuffworks.com/refrigerator2.htm

Edited July 19, 2010 by Speedwheel

[alan_fincher]

Agree with all that has gone before.......

 

As it will draw at least 8 amps continuously, rather than the 1.5 to 2 amps intermittently of a compressor type, you can really only run on 12 volts if moving, so the alternator takes the extra strain directly without caning you batteries.

 

Daft though it sounds, for many of them, if you really must run them off the batteries, you are better accepting inverter losses, and running them on the 240 volt input. Unlike the 12 volt heater, this does generally have a degree of thermostatic control, so it should actually switch off when cold enough, which it will not usually do on the 12 volt heaters.

 

I still wouldn't do it though - they really are only sensible on gas.

 

We do now run ours on mains if on the home mooring with a land-line - some time I really should work out whether that costs more or less than the gas method!

[Liam]

When on the moorings they are fine as they have a metred land line...

 

240v isn't an option unfortunately, well at the moment anyway, for some reason, when you have the engine on more than tickover it kicks the inverter out, it starts up OK again once you switch off and on again but it does the same when you start putting more than a couple of amps into the batteries. It's OK when you're tied up at the end of the day but if you're going to be doing a day of more than a couple of hours it's not really good.

 

New fridge or new inverter?

[sociable_hermit]

Another thing to bear in mind is that the fridge on 12V will be pretty useless at keeping things cool, despite hammering your batteries.

 

Gas works well but you'll be changing bottles all the time.

 

Personally I'd run it off the mains when on a landline, and use a small inverter when you're out and about. The gas installation on mine was dodgy so i bought a 350W inverter for about £120 and that does the job quite nicely. I know those 3-way fridges aren't particularly efficient on mains, but hey it works.

[Radiomariner]

There are quite a few 12V compressor fridges on the market. But they are a bit more expensive. My Batts fridge for instance cost almost double that of a normal 230V one almost 16 years ago. Still runs ok. Compressor takes about 3A when running. When the fridge compartment has cooled and the door kept shut, the compressor cycles for approx 4 minutes on and about 35 minutes off, which I think works out around a more respectable 7.6 Ah. This of course varies with ambient temperature and the fridge setting.

I would not recommend Batts (I believe they are gone now anyway) although electrically sound, after a mere 16 years the plastic coating on the shelves is cracking and rust showing through, and the bar that holds six cans of beer in to the bottom shelf of the door has been held on with gaffer tape for the last 12 years And oh yes the thermostat knob broke off and had to be glued on. SWMBO complains that what used to be white lining is no longer very white and that the rust along the underside of the door is causing chips of enamel to come away from the front of the bottom of the door! Bless her

Edited July 19, 2010 by Radiomariner

[Speedwheel]

Gas works well but you'll be changing bottles all the time.

 

I would disagree with this. I have found gas fridges to be quite economical on gas. I'm sure there was someone on here who commented that they had their gas fridge on for well over a month (42 days I think) with just one 13kg bottle.

Edited July 20, 2010 by Speedwheel

[alan_fincher]

Gas works well but you'll be changing bottles all the time.

 

I would disagree with this. I have found gas fridges to be quite economical on gas. I'm sure there was someone on here who commented that they had their gas fridge on for well over a month (42 days I think) with just one 13kg bottle.

 

The current (fairly small) RM4210 model quotes gas consumption at 310 grams per day. (Unlike a compressor fridge, I think that will be fairly constant if you run it on highest setting, as there is no thermostatic control).

 

That seems to work out at about 42 days from a 13KG cylinder, if it were being used for nothing else. I just paid a staggering £24 for a 13KG refill, so just under 60 pence a day to run on gas - not without cost, then, but worth it for milk, butter, cheese etc. that is not rancid - not to mention chilling white wines.

 

On the mains it claims to use 2.3 Kilowatt Hours per day, so if you are on land-line electric, and not paying through the nose, this would be cheaper, (maybe half the cost of gas). But if you were generating the electricity with a boat engine's alternator, my guess is the gas works out cheaper.

[Speedwheel]

310 gpd is about right but some on the new ones are a bit more economical going down as far as 200 grams. Some of the cool boxes are better still at around 150-170.

[WotEver]

I would disagree with this. I have found gas fridges to be quite economical on gas. I'm sure there was someone on here who commented that they had their gas fridge on for well over a month (42 days I think) with just one 13kg bottle.

Is this a new one or one of the old models? The Electrolux we ripped out of Wot Ever would go through a 7kg gas bottle in around a week.

 

Tony

[alan_fincher]

310 gpd is about right but some on the new ones are a bit more economical going down as far as 200 grams. Some of the cool boxes are better still at around 150-170.

I deliberately picked a small model with higher consumption for my numbers, even though I could see bigger ones quoted as using less.

 

This seemed fair, as most people are unlikely to have the latest models, now that the BSS try and discourage new fitting of gas fridges. Far more likely they will be a bit older design.

 

My manual for our 15 year old one is on the boat, but IIRC, consumption is quoted at about what I gave above, so even a 7Kg cylinder ought to last at least 3 weeks, though clearly the smaller cylinder you have the more any LPG actually ends up costing you (6KG Propane around £19, but a 13KG holding more than twice as much around £24).