Domestic fridge not working on 12v, any ideas. (1 Viewer)

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Barney23
Dec 27, 2013
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Have you got 12 volts present at the fridge with the engine running ?
Yes, works on 12v with engine running,
Am I being a numpty ?
When not on hookup, should fridge work off leisure battery or just gas ?

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glenn2926

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Sep 11, 2012
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It only works on 12volt with the engine running. I don't think any work on 12volt without the engine running.
 

TheBig1

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many many years! since I was a kid
only the latest 3 way fridges are able to run on 12v from solar power. normal old fashioned 3 way fridges would flatten a battery very quickly, so are only useful when run using the alternator
 

tonka

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As above.. 12v is for when engine is running and helps maintain temp while travelling.
It does not cool, just help to maintain the temp..

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Apr 27, 2008
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As above.. 12v is for when engine is running and helps maintain temp while travelling.
It does not cool, just help to maintain the temp..

Many fridges, mine included, cool very well on 12v. There is no thermostat so runs continuously and a theoretical risk of freezing if driving round the clock. The improved airflow over the back of the fridge while moving is possibly a factor as my previous MH had the bottom vent on the side of the MH and the top vent on the rear, leading to a howling gale over the back of the fridge when moving. I have had many motorhomes and the fridges all vary, even if the same model of fridge. My present one is at it's least effective on mains.
 

tonka

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Many fridges, mine included, cool very well on 12v. There is no thermostat so runs continuously and a theoretical risk of freezing if driving round the clock. The improved airflow over the back of the fridge while moving is possibly a factor as my previous MH had the bottom vent on the side of the MH and the top vent on the rear, leading to a howling gale over the back of the fridge when moving. I have had many motorhomes and the fridges all vary, even if the same model of fridge. My present one is at it's least effective on mains.

I was always lead to believe they "maintain" after reading previous posts and FAQ on websites..
Always like to stand corrected.. To be honest i dont think I have ever switched ours to 12v in 5 years, just fire up the gas when we stop.. (y)
Mine is rubbish once you get into Spain and a bit of heat, will have to look at fitting some of those fans.
 

Silver-Fox

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@tonka yes you are correct.
After the issue we had with the fridge over the weekend I had a good read up on the three way fridge.

12v engine running (maintaining temp)

240v on hook up (temp to what is set)

Gas when parked up (temp to what is set)
 
Aug 20, 2007
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My Domestic handbook for our tower fridge (7**** series) says that all three energy sources are thermostatically controlled.
My experience of 12 volt cooling is that I can put stuff in the fridge and the freezer part, without any pre-cooling of the fridge, and all will be ok after arriving at chosen destination a little later.

Allen

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Aug 6, 2013
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I was always lead to believe they "maintain" after reading previous posts and FAQ on websites..
Always like to stand corrected.. To be honest i dont think I have ever switched ours to 12v in 5 years, just fire up the gas when we stop.. (y)
Mine is rubbish once you get into Spain and a bit of heat, will have to look at fitting some of those fans.
They are usually poor on 12v because no MH converter uses cable of sufficient cross-section - so the fridge is lucky if it sees more than 10 or 11 volts. The element is the same wattage as the mains one (give or take) so will produce the same amount of heat. Run a decent cable for it and it will freeze the fridge contents on a full days drive.
 

Stretto Boy

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Sorry Jockaneezer, it means you are a numpty :) Join the club of which I am the founder member. I made exactly the same mistake when I bought our first motorhome : complained to the dealer that the fridge wouldn't work on 12 volt. They said, "have you turned the engine on?" Sent straight to the Stupid Step :) So you are not alone!
 
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Sorry Jockaneezer, it means you are a numpty :)

I've been called worse and deservedly too sometimes but in this instance I was trying to establish if there was voltage present with the engine running as sometimes the split charging relay that takes the juice from the running alternator to the fridge fails and can't power the fridge's 12 volt element. But keep that membership of your club open, I'm more than capable of qualifying to join anytime. :)

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Stretto Boy

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Sorry Jockaneezer, you have lost me there. I am starting to think that I may have to revoke your membership of the Numpty Club on the grounds that you are far too clever to be one of us! :LOL:
 

PeteH

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In the past the design was ONLY to run off 12V (relay controlled) with the engine running. The current draw will discharge a Battery extremely quickly. Some of the early Gas/12v fridges had to be wired via the Second 7 pin (S) plug, for use whilst travelling (towing) caravans. When fitted to Motorhomes they needed the relay to prevent discharge when stationary. I found this out the "hard way", having stopped for lunch, the Frig; in the Caravan, discharged the Car battery:( and I had to get a "Boost" from a friendly car driver to get restarted, (y), after which experience I fitted a relay in the boot of the car to prevent it happening again!!..
 

Lenny HB

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They are usually poor on 12v because no MH converter uses cable of sufficient cross-section - so the fridge is lucky if it sees more than 10 or 11 volts. The element is the same wattage as the mains one (give or take) so will produce the same amount of heat. Run a decent cable for it and it will freeze the fridge contents on a full days drive.
A bit of a sweeping statement I think you must referring to British built Motorhomes as the cables size in the 3 German van we have had are more than large enough for the job.

The red & white wires are the main 12v to my fridge.
P1100604.JPG

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Aug 6, 2013
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A bit of a sweeping statement I think you must referring to British built Motorhomes as the cables size in the 3 German van we have had are more than large enough for the job.

The red & white wires are the main 12v to my fridge.
View attachment 158616
I fitted a socket near the hab door to run a cool box. I wired it to the fridge feed so it would only operate when the vehicle was moving. One of those cheap plug-in voltmeter s (checked with a multimeter) never sees more than 11.5 volts. The van is 2005 Hymer. Previous MHs have never achieved 12v either. For the industry standard 3‰ volt drop over 5m the minimum cable size is 6 sq mm.
 

Lenny HB

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Oct 18, 2007
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I fitted a socket near the hab door to run a cool box. I wired it to the fridge feed so it would only operate when the vehicle was moving. One of those cheap plug-in voltmeter s (checked with a multimeter) never sees more than 11.5 volts. The van is 2005 Hymer. Previous MHs have never achieved 12v either. For the industry standard 3‰ volt drop over 5m the minimum cable size is 6 sq mm.
Just checked my Hymer, 12.9 v at the fridge with the engine running. If I switch the fridge to 12v so it's running off the habitation batteries it drops to 11.9v but with the 15 amp load and no charging the hab batteries are pulled down to 12.4v
 

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