Fridge Power

[SteveA]

With the high cost of 12v fridges I'm considering fitting a normal 240v domestic fridge instead along with an inverter. The trouble is I can't find out the maximum power these use - can anyone help.

The fridge I'm thinking of is an LG which is quoted as using 181kWh/year.

SteveA

 

[byron]

12/240 volt Fridges are substantially cheaper from a caravan outlet.


http://www.alexander-advertising.co.uk

 

[dick_james]

Beware of buying an absorption fridge ( the type used in caravans that run on 12v, 240v and gas) They need lots of ventilation at the rear, and as they usually back up to the hull, that can be difficult. Plus they are sensitive to being level and can take a while to cool down. I got so frustrated with mine I eventually ripped it out. There was a thread on this forum a while back on using small domestic 240v fridges via an inverter. Try searching it up.

 

[VMALLOWS]

It's feasible. The 'running' power will be about 50-85w. with a duty cycle of about 1 in 4. However the start up current when the compressor starts will be 2-3amp for about a second (500-1000 watts) so the inverter will need to be able to handle that.

Can you find a domestic fridge small enough? (of course don't know how big your boat is!). Many of the really small ones are absorbtion fridges anyway so might as well work on 12v or gas.

Your annual KwH figure sounds about right.

 

[VMALLOWS]

12v/240v/Gas Fridges

I think it depends how you use your boat. I've got one (a top loading Electrolux) that I've had over 20 years thats still going strong and does a good job. As you say won't work unless nearly level, and I switch it off when sailing, but great when at anchor for any length of time (or motoring in flat calm, or in the canals).

Incidentally, it became useless on gas this season (though fine on electric)........the injector nossle neaded cleaning. Also, if anyone buys one secondhand, check if it requires 28mb (usual UK standard) or 50mb (Germany and others). Calor do now have 50mb regulators available.

 

[SteveA]

Many thanks for the replies - I don't want an absorbtion unit because of the problems they cause.

Our boat is a Moody Halberdier so we can fit a fairly large unit.

From looking at the price of inverters I would hope that a 500W unit could cope but I don't want tho invest in this until I know that it would work.

 

[DavidGrieves]

Have a look here for an inverter http://www.ardelectronics.com/
I bought one, it works fine.

 

[andyball]

The better quality inverters usually quote a surge rating up to 2.5X greater than the continuous one.....so a decent 500W one may well be enough.

However, I've blown up 2 "cheapies" (I say cheap, this was a few years ago, and £90 for 200W doesn't seem cheap now) when using them as a back-up supply for an aquarium (no lighting, it was the start-up of a pond-pump that wrecked them,even though I wasn't using the inverter at full capacity.

These were made by Switched mode ltd, & I wouldn't bother with them for running any kind of electric motor,the waveform was OK'ish for using a mains drill, but that was about it...anything else was slow/sounded odd.

 

[Petercatterall]

Have been considering this as my fridge needs replacing. My thoughts were that I would use the fridge mainly on shore power but via an inverter when motoring. Possibly extra insulation or a chest type freezer would help avoid rapid warm up.
I have seen some reports on the power requirements, try a search. One issue is the higher load on start up and then of course batterydrain.
My present thought is to try the 12 volt/gas fridge again my original fridge was installed without ventillation which could have been a disaster.

 

[SteveA]

Thanks for the advise - I think I've finally decided on a 12vdc-ac inverter of 1000w continuous rating costing £89.99 from ardelectronics and an LG fridge costing £99 from Argos ( 24-7electrical have these listed at 89.00 but then quote a delivery charge of £34.99!!) The advantage of this fridge is that it is only 440mm wide.

 

[neale]

I have gone down this route. Got a 240v Fridge from Makro £69.99 + vat. Is almost exactly the same size as a small marine fridge and uses around 80watts when running. The problem is trying to get it to run on an invertor because of the start up power which I have yet to find out how much it is. So far I have found that using on shorepower and keeping dore shut as much as poss while underway seems to keep it cool until back on shorepower. But this is on a motorboat which is only underway for 2-3 hours at a time.

Neale

 

[Petercatterall]

Steve,
Have you the address for the inverter? £89 for 1000 watts sounds good. I think I may go for your solution rather than re-installing my existing '3 way' fridge so as to get the fumes out of the saloon!!

 

[SteveA]

Peter, Have a look at www.ardelectronics.com - this is where i found them.

SteveA.

 

[Mr Cassandra]

Hi .do motor boats realy go for 2-3hrs {joke]
cheers bob t

Bob T

 

[ccscott49]

I run a domestic freezer onboard, which is on continuosly (of course) with a 1000w inverter, no problems atal! I would go with the domestic fridge, the insulation is just as good as the "marine" variety and a lot cheaper, also you will use your inverter for other things, so invest in a decent sized one.

 

[pheran]

1000watts start-up requirement - doesn't this equate to 80 amps @ 12v? Will the 12v wiring cope or does the very short time make it not a problem? What sort of fuse do you use in this circuit? Or perhaps I've got the sums wrong (again!!)

 

[VMALLOWS]

No, your sums are spot on. If you intend to use your inverter to 1000w you will have to cope with that current in the wiring and fuse (and battery capacity!!). If you realy only intend it to run the fridge, then you'll probably get away with about 40a cabling /fuse. (A magnetic, as opposed to a thermal breaker or fuse, may however trip out, depending on the trip characteristics). As reinforced by many posters, go for a 1000w minimum inverter.

 

[Petercatterall]

I am interested in using a similar set up.I guess that siting the inverter is important? Somewhere near the battery, with ventilation (and dry) I guess?
I suppose that fixed 'domestic' wiring from the inverter to the fridge would be ok or possibly to a single socket so that the fridge or another device could be plugged in.
I am concerned at the heavy battery demand but I suppose that using it just to preserve the coolness of the fridge and only when motering would be OK?
(I do like ice in the old G&T !!)

 

[VMALLOWS]

All your comments regarding location/wiring etc correct.

The start-up current is insignificant in terms of battery drain. The running current should average around 2 amps per hour. Only you can decide if this is an acceptable load. (for example, a typical 100Ah yacht battery will be well on the way to being flat after a night at anchor with the fridge on, lights etc.

IMHO, of course!

 

[Guest]

We have fitted inverters and mains fridges in numerous boats in commercial and private use and find that the set-up uses no more 12 volt capacity than the old 12 volt Engel fridges did. The inverter will also be useful for your hair dryer etc (1200 - 1400 watts!) so size IS important. I recommend: 1500 watt continuous sine wave 9or at the least quasi sine wave) inverter from Victron or Mastervolt (have had lots of bad experiences with several other makes, never with Victron or Mastervolt), locate inverter as close to your batteries as possible with big heavy cables, dedicated switch and heavy duty fuse, and install a 30ma RCD on the output plus of course a suitable circuit breaker. You will find the installation invaliable for all sorts of things and will regret buying cheapo gear when it breaks down!