# 3 Way Dometic Fridge/freezer



## 97201 (Jan 7, 2006)

I have one of these which works off gas and also when the genset is running. Should it also work off 12v when the main engine is running?

If it is down to the wiring, where do I begin to look to see which way it is wired up?

Ian


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## geraldandannie (Jun 4, 2006)

Ian - how do you know it's not running? Bear in mind that when running off 12V, it doesn't cool - only mainrain the temperature.

Gerald


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## Scotjimland (May 23, 2005)

Hi Ian 

Are you certain it's 3 way ? Many RV fridges are only gas and mains.. with no 12v.


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## gaspode (May 9, 2005)

Hi camperian

If you take the lower vent panel off, you should be able to identify the 12v heating element quite easily. It will have two quite thick wires going in, usually one black and one red. Using a test meter set to DC volts, turn off the generator and the gas (and unplug the hook-up if you have one), switch the fridge to 12v operation, hold the test meter leads onto the 12v heater terminals that you have identified and start up the engine. You should see that a voltage appears across the two heavy wires of 12-13 volts. If this happens then it is wired up for 12v operation. If it isn't wired for 12v then I wouldn't expect to find any 12v wiring going to the 12v heating element.


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## 97201 (Jan 7, 2006)

Hi again ScotJimland

You may be well right on this. But as it was stationary for (approx 3 weeks) and used up about £19 of LPG Iwas wondering how I was going to fare in S/Spain

Gaspode

I am a total novice at electrics. I have just bought a multi-meter from Maplins which automatically adjusts its reading and will look for wiring under the unit.

The current problem is I pay a rent to a local farmer for my RV to stand on his land (2mins away) but my left eye is watering as 5 Norwegian girls have camped in his next field and the binoculars are a bit of a strain !!!!!

Ian


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## gaspode (May 9, 2005)

Hi Ian

If you don't have a clue about electrics, just PM me your address and I'll be along within the hour to help you out (about what time do the lovely gals go to bed by the way?) I've got a very good set of long range night vision binoculars I could bring with me for you to try out if that's OK. :lol:


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## 88927 (May 10, 2005)

No wonder your fridge ain't cooling Ian :lol: :lol: :lol: :lol: 
Don't forget to take your mack with you Ken, it might be raining :lol: :lol: 

Keith
Ps Jim I think is correct, our fridge is only gas or mains.....


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## LC1962 (Oct 6, 2005)

kands said:


> Ps Jim I think is correct, our fridge is only gas or mains.....


Listen to the boys Ian........your fridge is not designed to run 12v.

Cheers
Linda


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## 97201 (Jan 7, 2006)

Guys 

Thanks for the offer of assistance........but I think I can manage by myself! As far as the local inhabitants are concerned.

Ian


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## vicdicdoc (May 14, 2005)

I can't help on the technical points of fridges but I like bird watching too - can I come ? 8O


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## 97201 (Jan 7, 2006)

Linda

Did you receive my PM about windscreens?

Ian


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## 97201 (Jan 7, 2006)

Vic


Of course..............as long as you provide the booze, video etc

Ian


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## 97201 (Jan 7, 2006)

I can't help having a sense of humour      
but please guys, does this mean I should install a Gaslow system for (Spain mainly) and France. 

What is the cost of this addition?

Must the bottles be kept in an upright position?

Ian


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## LC1962 (Oct 6, 2005)

camperian said:


> Linda
> 
> Did you receive my PM about windscreens?
> 
> Ian


Hi Ian

James replied...did you not receive it?

Regards
Linda

Edit: Ian....have looked in my outbox and James's pm is still there...........


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## 97201 (Jan 7, 2006)

Thanks Linda

Got it now. Had to go offline as the buyer came round with the readies to pick up my Jaguar.

I now have some dosh to continue with the various upgrades........not forgetting the roof :roll: :roll: :roll: 

I have found that a plastic fridge scraper is quicker at removing the gunk than my fingernails!

Ian


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## richard863 (May 1, 2005)

Hi All 
I have a Dometic 76501L. I am a little confused over messages on this thread. 
On 12 volt selection when in freeze and getting up to temp mode it draws just over 14A. If this is only keeping cool, thats one hell of a drain! The destruction manual in bold print quotes "Do not use 12V if engine not running. No-where does it say anything about just being in keeping cool mode, mind you they wouldn't admit to that anyway. 
When on a X channel ferry & I use the 3Kw inverter it draws just under 16A when in anger from the 2 x 98A/hr cells, if I'm lucky to be out on deck, you can hardly see any appreciable drain, on the I'm sure quite inaccurate control panel. 

So please where does this just maintaining the temperature and not really working come? Am I just not reading this correctly or do I have my Hings twisted.

Kind regards


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## Scotjimland (May 23, 2005)

richard863 said:


> So please where does this just maintaining the temperature and not really working come? Am I just not reading this correctly or do I have my Hings twisted.


Hi Richard

The 12volt element is lower rated wattage than the 240v one to reduce the power required from the 12v system and it's primary use is to maintain temperature rather than pull it down from ambient. Unfortunately many convertors don't install a heavy enough 12v supply cable which reduces the efficiency due to volt drop.
Best practice is to put the fridge on mains for 24hrs or longer prior to travelling and keep the fridge as full as possible during the journey..


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## DABurleigh (May 9, 2005)

Though for a RM 7651L+ (if that is Richard's for I couldn't find a 76501L):

Max input 12V (W) 170 
Max input 230V (W) 200 

Not a lot in it.

Dave


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## Scotjimland (May 23, 2005)

DABurleigh said:


> Max input 12V (W) 170
> Max input 230V (W) 200 Not a lot in it.


Hi Dave

Quite so, 15% doesn't seem much .. but this plus the volt drop all adds up.. by my calculations, this fridge should have 10 mm cable ( I assumed a 5mt run with a max 4% volt drop) .. how many fridges are installed with the correct size cable ?

PS, at night 15% can matter a great deal :wink:


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## gaspode (May 9, 2005)

richard863 said:


> Hi All
> I have a Dometic 76501L. I am a little confused over messages on this thread.
> On 12 volt selection when in freeze and getting up to temp mode it draws just over 14A. If this is only keeping cool, thats one hell of a drain! The destruction manual in bold print quotes "Do not use 12V if engine not running. No-where does it say anything about just being in keeping cool mode, mind you they wouldn't admit to that anyway.
> When on a X channel ferry & I use the 3Kw inverter it draws just under 16A when in anger from the 2 x 98A/hr cells, if I'm lucky to be out on deck, you can hardly see any appreciable drain, on the I'm sure quite inaccurate control panel.
> ...


Hi Richard

I think that this popular misconceptions stems from the fact that most 3 way fridges don't have any thermostatic control on the 12v supply mode (or on the gas mode in many cases). This means that whenever the 12v is switched on there is a constant (but reduced) amount of cooling power available which will either cool the fridge or just maintain temperature dependent on ambient outdoor temperature. In hot weather it may not be able to cope for long periods. On the 240v mode, the heating element is bigger so a thermostat is used to prevent over-cooling (although experience shows that even the 240v mode will struggle in really hot climates). All 3-way fridges work on the absorbtion principle rather than the much more efficient compressor principal of the normal domestic fridge.


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