12 volt fridge problems

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Mark M

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Hi Guys

I am wondering how long my fridge should run before it flattens my battery

I have a old 12 volt Electrolux fridge in the boat that I purchased last year, and have never used the fridge up to now.
Its fed from a new house battery which is rated at 120 Amp Hours, but the fridge flattens the battery within approx 10 hours if the engine is not running and charging the battery.
I did measure the current to the fridge on a multimeter and it was drawing approx 5 amps when first switched on, so i thought I would at leat get 20 hours use from it.

How long does you guys fridge run before flattening the battery?, or can you recommend a good efficient fridge

Cheers
 
A 12v battery with a capacity of 120Ah when new (it drops with age) will only provide 60Ah of useable power before it drops below 50% at which point is is suffering and too many such 'deep' cycles will destroy it in quick time. Don't assume that a normal engine alternator and regulator will recharge a battery to 100%, that takes a 'smart' regulator and more time than you might imagine, so your nominal 120Ah battery may start at only 105Ah.

5A is about what a fridge takes when running but it should not be running continuously, how much will depend on how well insulated, how often it is opened up and what is inside that needs to be cooled down. A front loading fridge, what I guess you have, is the least efficient as it drops all the cold air out every time the door is opened, a top loader is much better. A full fridge once cooled down will take less power to keep it cool than an empty one and considerably less than one you have just stocked with lots of cans of warm beer.
 
10 hours sounds about right, bearing in mind that at 50% + discharge even a deep cycle battery is effectively nearly flat in a high current demand situation. In caravan or motorhome use Electrolux fridges are designed only to use the 12v supply to keep the fridge cold in transit while the engine is running because of the high current demand. A relay on the towing vehicle supplies current only when the alternator is charging. The 12volt element is not intended as the primary power source, and modern ones cut over to gas or mains automatically once the van is disconnected from the car.

Refrigeration requires quite a lot of power in an absorption fridge, unless you are happy to use the gas setting aboard, with the attendant risks.
 
Robin said:
5A is about what a fridge takes when running but it should not be running continuously,
Click to expand...

The old absorbsion type electrolux fridges do run continuously when on 12V - The thermostat only comes into play when on a mains supply.
I had one before and they are horribly inefficient on a 12v supply.

The fridges with a compressor are much more efficient and will also use a thermostat on 12V.

The OP will need a lot more battery capacity, and the means to charge it effectively.
 
BGW said:
The old absorbsion type electrolux fridges do run continuously when on 12V - The thermostat only comes into play when on a mains supply.
I had one before and they are horribly inefficient on a 12v supply.

The fridges with a compressor are much more efficient and will also use a thermostat on 12V.

The OP will need a lot more battery capacity, and the means to charge it effectively.
Click to expand...

Or replace the fridge. We fitted the little Isotherm unit into a coolbox. Uses about 20 amps a day. Turn it up any more and the milk freezes.

Pete
 
Electrolux Refrigerators

Hi,

I am new to the forums so I hope I will meet helpful people and can offer helpful suggestions. I too have an Electrolux Refrigerator and it keeps failing to cool after a short while with a faint ticking from the compressor, and I am sure ithas destroyed one 110AH battery (fortunately under warranty). Further investigation has revealed that an electrolytic capacitor on the control unit PCB keeps exploding (Well not quite exploding but bursting at the seems). The cap is across the supply so this may be because the compressor is drawing too much current. Can anyone assist me going further with a circuit diagram?

The model is RB2165 (I know it is old but I am reluctant to discard it)
Not sure of the product code as it has half disappeared.

Thanks In advance?

I hope the info has given other people another direction to look in. The Cap is a 200/220uF 50v Electrolytic.
 
oliflash said:
Hi,

I am new to the forums so I hope I will meet helpful people and can offer helpful suggestions. I too have an Electrolux Refrigerator and it keeps failing to cool after a short while with a faint ticking from the compressor, and I am sure ithas destroyed one 110AH battery (fortunately under warranty). Further investigation has revealed that an electrolytic capacitor on the control unit PCB keeps exploding (Well not quite exploding but bursting at the seems). The cap is across the supply so this may be because the compressor is drawing too much current. Can anyone assist me going further with a circuit diagram?

The model is RB2165 (I know it is old but I am reluctant to discard it)
Not sure of the product code as it has half disappeared.

Thanks In advance?

I hope the info has given other people another direction to look in. The Cap is a 200/220uF 50v Electrolytic.
Click to expand...
Is the capacitor the right way around? Is the fridge connected the right way around?
 
most fridges on 12 volt only last a maximum of 10 hours on a good day without charging. My Waeco CR50 (old) has its own 110 amp battery charged separately by solar/wind and still on hot days when it has to work hard switches off in the early hours until the batter can catch up.
 
Electrolux refrigerator

Thanks Elton and Steve,

Aware of polarity, and checked both the cap and supply lines all OK. Thanks anyway.

I just need a better understanding of what it is I am actually seeing, I have tried to trace the circuit and all I have come up with so far is a the +ve and
-ve from battery and the cap directly across in parallel with a diode which incidentally is reversed presumably to either filter spikes or is a zener diode, and the compressor, but of course there's the control lines to the compressor which will either increase or decrease compressor load depending on temperature and thermistat blah blah and it is the control side I need to work out. Presumably if the compressor is constantly working at full capacity then the current draw will be excessive which may be what is destroying the cap, and eventually the battery.

I need to know what I should be seeing at various points in the circuit (good old fashioned half split fault finding) voltage and signal wise.

Can any one assist further?........... please?

Thanks again guys
 
Could it be that the capacitor is being (too) rapidly discharged through the starter motor when you start the engine with the fridge turned on? It depends on where it's connected and the thickness of the cabling, but the starter motor could momentarily draw more current from this capacitor than it does from the battery.
 
I have a Waeco Coolmatic. Draws 4 A to run the compressor, and probably runs for 20-25% of the time, so with my 110 Ah battery, assuming 50% capacity, would run for at least 3 days, assuming no other draw on the battery. However, using lights/TV etc at night means that I recharge every day.
 
Electrolux Refrigerator

Elton,

Wow now there's a thought. Because I do generally have the fridge running before the engine to get it cold for the day. I will certainly give it a go for the next few trips.

Food for thought, so thanks again.
 
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