Dometic Fridge not working on 12v? (1 Viewer)

[tonywolst]

I say not working, it only works when I'm driving, I just assumed it wasn't working as when I turned it to 12v no light came on, However today the misses noticed the light was on when the engine was running, Has it been wired up wrong, ie to the engine 12v circuit and not the leisure circuit, or is this how they work, so 12v only whilst driving, then onto gas or ehu?

 

[sillybug]

think thats how they work well i always assumed that 12v worked while we were driving then when we stopped either plugged in electric or put on gas maybe somebody will correct me if im wrong but thats how mine works hope this helps:thumb:

 

[Simba]

On my MH 12v only works when engine running when on site use gas or EHU. Thats the way it is set up.
Bill

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[welshbois]

That is what It seems. Works on battery while driving and acts as a chiller. When parked up go on gas or EHU.

 

[tonywolst]

Thanks All.

 

[activecampers]

By design.

3 way fridges can work on 12v but only to "maintain" temp, not cool (so the theory goes, but ours cools). The power draw is quite large (10A? Ours is fused at 15A), so that will flatten an 80AH battery in 8 hours!!!!

So there SHOULD be a split charge relay (or voltage sensitive switch) that when the engine is running and hte alternator is making the vehicle voltage above 13.6v it connects the vehicle 12v to both the fridge 12v to run the fridge, and to the leisure batteries to charge them.

Without this switch in place you would flatten your vehicle battery

You CAN get 12v fridges but these are "compressor" fridges, typically a bit smaller, and typically the vans have extra batteries to cope.

A 3-way fridge should not run off the leisure batteries (though some may be connected to the AUX on the leisure side to run the fridge electronics/gas ignitor only etc)

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[wizzer59]

so 12v only whilst driving, then onto gas or ehu?

Correct:thumb:

 

[tonka]

Slightly off the original point of the topic but may be of use to someone..

We had a trip once back up from Spain and put the fridge on 12v to keep to cool while traveling, however the trip was in rubbish weather and a bit cool. So we had headlights on, wipers goin, radio on, heater blowing.. You get the picture..
Outcome was of course the alternator struggled to keep up with it all and put very little charge in the leisure battery.. That night we got by but leisure battery was very low..
Later discovered just how thirsty the fridge is on 12v (10 amps)...
So just be careful if you rely on having your leisure battery charged while driving..

 

[callumwa]

Our old van had the Dometic fridge with manual control.

ie switch to 12 v for when the engine is running, and gas or 240v when stopped.
But you had to switch it so it works.

Our current van has auto system which switches to 12v when engine running, 240v when on EHU, and gas at all other times. :thumb:

Much easier as I always forgot to change the manual control on the old van so got fed up with warm beer nd wine.........oh:

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[peaps]

Hi
our van has the same as your old van just as many before and as tuggers many years ago the 12v and 240v get left on permanently and I just light the gas when required, never had any problems in 30 plus years HTH.

Pete:thumb:

 

[Taran_Las]

One recommendation given to me was to run the fridge on EHU for a couple of days (before your journey) to chill off. The 12v will keep the contents chilled. If you don't do this running on 12v will keep the contents nice and warm!

 

[Reaynger]

Wouldn't a solar panel kit keep the fridge running so we can be independent from EHU and gas? Seems it is a bit daft that you can't run a fridge on a really sunny day whilst selected to battery. Or does that change when you get the solar?

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[activecampers]

Wouldn't a solar panel kit keep the fridge running so we can be independent from EHU and gas? Seems it is a bit daft that you can't run a fridge on a really sunny day whilst selected to battery. Or does that change when you get the solar?

If you get a big enough solar panel it can - but 5-10A constant for a 3-way fridge. and then what about overnight?

A smaller compressor fridge that only runs on 12v is a bit cleverer, and at 5A draw at, say, 1/3 of the time, needs 40AH per day. So as long as your 80W (5A) solar panel has full sun for 8+ hours...... (or 160W for 5-6 normal hours...)

So doable but just do the math

 

[Rayb182]

On our Kontiki I just put it on auto and it will either run on battery when driving, solar if theres sun, or it will change by its self to gas when theres no sun.

 

[pappajohn]

By design.

3 way fridges can work on 12v but only to "maintain" temp, not cool (so the theory goes, but ours cools). The power draw is quite large (10A? Ours is fused at 15A), so that will flatten an 80AH battery in 8 hours!!!!

Close, but no coconut

you should never discharge a battery to below 50% of its fully charged state, so an 80ah battery will last 4hrs at 10amp drain.

go below 50% and you run the risk of damaging the battery permenantly. :Sad:

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[aba]

so i guess that my battery took a bashing when it got down to 10.2volts thenoh:oh:

 

[pappajohn]

so i guess that my battery took a bashing when it got down to 10.2volts thenoh:oh:

yep!!! 10.2v is considered a dead battery....not just flat, but dead.

you may get away with it once or twice but certainly not every time.

i believe it depends, to some extent, on how long it was at 10v before recharging.

 

[aba]

not long as i started the engine and let it run for 20 / 30 minutes it seems to have recovered as it sits quite happily at 12.8 volts

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[activecampers]

Close, but no coconut

you should never discharge a battery to below 50% of its fully charged state, so an 80ah battery will last 4hrs at 10amp drain.

go below 50% and you run the risk of damaging the battery permenantly. :Sad:

It was only for illustrative purposes, and you are close but no bananas, see http://www.elecsolbatteries.com/faqs/#07 - some batteries are fine with deep discharge So if you have the elecsol batteries, you could drop more...

not long as i started the engine and let it run for 20 / 30 minutes it seems to have recovered as it sits quite happily at 12.8 volts

No - voltage may recover but that doesn't indicate it is full. Even if needle/meter in green. No simple/cheap way to see state of battery charge from a meter. 30 mins at, say, 20A charge only adds 10AH to your batteries - so misleadng I am afraid Only way I know is to have a clever unit measing current in/out and then calculating capacity.