I have an odd issue with the fridge in my van, a 2009 Swift Challenger 580.
I can't remember the fridge model but it is shown here:
http://www.jamesonline.net/vanlife/caravan_gallery/20200115_Simon/Simon_10.jpg
It is a 3-way fridge and works fine on gas and 240v and on 12v when towing, but not on 12v when standing. The screen shows a spanner icon and the blue light flashes.
I have checked all the fuses and wiring I can easily see and all are fine. I reseated every fuse just in case but it still won't work.
Is there a secret fuse hiding somewhere or what else do you suggest?
As far as I know - and many other threads have said so too - 12v only cools the fridge when you’re towing, when the engine running is keeping the leisure battery topped up.
If it's a 3 way fridge, regardless of make/model/age, it's simply not intended to run off caravan's inbuilt 12v leisure battery! The reason being is that it's typically rated around 100-120W, drawing 8 - 10 amps from the 12v power source, which is sufficient to kill a typical leisure battery stone dead in a few hours! .. and indeed beyond normal discharge limits but way into fatal damaging irrecoverable discharge region!
The reason it works when hitched to tow vehicle is that it's effectively drawing power from the alternator rather than the (vehicle) battery, which is why (if correctly wired) it only works when the engine is running.
All that said, it DOES require a 12v supply from the caravan battery to power the very low demand control panel circuitry which controls use under any of the 3 power sources. The warning lights are almost certainly (I'm not familiar with your particular model) indicating that the 12v supply for cooling is absent.
Both the users manual for the caravan and the specific manual for the fridge should be easily obtainable from the internet with a bit of Googling, they will explain the operation and warning lights in detail.
It does appear that your fridge is working perfectly as intended.
The manual for the fridge says it can be used to maintain temp once cooled by either gas or 240v but I guess it is lying and the wiring for that is absent as said above.
Oh well, I would normally use gas when not hooked up anyway.
Quote: Originally posted by MikeJames on 03/1/2022
OK thanks.
The manual for the fridge says it can be used to maintain temp once cooled by either gas or 240v but I guess it is lying and the wiring for that is absent as said above.
Oh well, I would normally use gas when not hooked up anyway.
No it's not lying, it's a true fact and spot on if you read it properly. It's a well known fact that once the fridge has been pre-cooled by means of gas or 240 mains, the 12 volt supply then maintains that temperature of the fridge whilst towing and the engine running. if initially the fridge is warm the 12 volt power is just not powerful enough to lower the temperature over such a short time.
Quote: Originally posted by MikeJames on 03/1/2022
OK thanks.
The manual for the fridge says it can be used to maintain temp once cooled by either gas or 240v but I guess it is lying and the wiring for that is absent as said above.
Oh well, I would normally use gas when not hooked up anyway.
No it's not lying, it's a true fact and spot on if you read it properly. It's a well known fact that once the fridge has been pre-cooled by means of gas or 240 mains, the 12 volt supply then maintains that temperature of the fridge whilst towing and the engine running. if initially the fridge is warm the 12 volt power is just not powerful enough to lower the temperature over such a short time.
True enough in effect, that they don't generally work as well on 12v when towing as with other power sources when stationary, but not quite true in terms of power being the cause. Both the 12v and 240v power demands are very similar, maybe only 5W difference with typically 120/125W ratings, BUT an absorption fridge is VERY sensitive to operating angle with only maybe 12-15 degrees tilt making the difference between not working at all and working perfectly! When towing, the fridge is constantly altering angle, indeed it probably has a permanent bias 'tilt' of around 5-8 degrees with the typical nose down attitude of a hitched van, with hills and road cambers compounding that, plus the liquid refrigerant will be 'slopping around' with movement rather than settled, so it is hardly ever operating at it's optimum, and that is the greatest cause of reduced performance! Wouldn't like to speculate too much what a 60mph slipstream racing over inlet/exhaust vents does to performance, but windchill may drive ambient temp around heat exchanger down towards the lower operating limits where the performance also suffers.
My van is in storage, so no chance of pre-chilling on 240v/gas, so it gets hooked up to car and fridge turned on to run on car 12v at start of trip, on longish trips it has cooled down substantially on the journey, when you consider how slow absorption fridges are to chill down (Dometic manual states "The refrigerator will take several hours to reach its operating temperature"), it's doing pretty well!
Our ancient caravan has at some time in its life been fitted with a mains-only domestic fridge. Not a problem for us as we always go to sites with EHU. It does mean that we can't run it from the car when towing, but that has never caused us a problem either. As the caravan is normally kept at home I just plug it into the mains the day before we go anywhere which cools it down nicely, then just before we go I put a couple of ice-packs in it from our home freezer and shut the door. When we get to the site the fridge is usually still lovely and cool.
The alternator in the car's intended job is to charge the car battery. It's control system will deliver power at a voltage to suit the car battery.
The car battery is very close to the alternator so there will be very little voltage drop.
The caravan fridge and leisure battery are a very long way from the alternator in terms of voltage drop at 12 volts. Limits are always in terms of percentage drop. At 12 volt, an element will use 20 times as much current to be the same power as a 240 volt element. The percentage volt drop of the 12 volt will be 20 times as much and its based on 20 times as much current.
So, sorry, but not much gets through to the van fridge.
With some modern cars, the car charging system doesn't fully charge the car battery so that some regenerative braking can be used to generate power for the battery. This will save fuel. When it stops charging the car battery it does so by reducing the voltage, so not delivering enough to reach your fridge.
Sometimes modern technology can have a negative effect in some ways. Many years ago I had a caravan that I towed with a Mk2 Cortina. Very few sites had EHU, and our caravan had no electrics at all when I bought it, just gas lights. I fitted a battery, some interior lights, and a charging wire using the (then) unused blue wire from a split charging system I made in the car. Despite the fact that the Cortina only initially had a dynamo rather than an alternator, the charge in the caravan's battery was always sufficiently replenished by the drive to our next site. How, I don't know considering the potential voltage drop, but all I do know is that it worked.
Can I just say, one of the reasons why it’s so worthwhile being on UKCS is reading posts from people who can explain electrics, as I never “did” it at school. So - thank you.
i have a Renogy 20 amp DC to DC charger fitted to my van.. this takes whatever voltage it gets from the car battery boosts it and puts 20 amps into the van battery.. the cars alternator provides the needed power to keep the car battery charged..
i also have a 1000 watt inverter which runs the vans mains power without a hook up..
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Topic: Swift Challenger 580 Fridge 12v
via mobile 03/1/2022 at 1:15pm
