Quite a few, judging by the number of forum posts about cars not being wired for the fridge!How many people have the fridge operating while towing as we have never felt a need for that option even when travelling to Spain?
We always set the fridge to run from the battery whilst travelling. But it was always brought down to temperature prior to departure and the food etc would be chilled in our domestic fridge prior to transferring it to the caravan fridge. Then with an overnight stop on the European trips it would be plugged in to EHU. But the discussion here raises doubts as to whether it worked or not. All I can say is that on arrival at our final destination the contents were still cool.
Yes and no.
Post #7 :-
The towbar electrics include a 'relay' in order to switch the fridge supply (pin10) on only when the engine is running. The permanent supply (pin9) has to be permanent so its not possble to install any relay in this line.
The caravan also features a habitation relay which switches the 12v over from the leisure battery to the Pin 10 connection when connected to the car.
So its not clear in your post #7 what relay you are refering to.
Keep in mind that while I and perhaps others could accept not having any power on pins 9 or 10, those who have ATC would need to have power on the permanent connection pin 9. In fact can those with ATC even be confident that it works 100% of the time and is not active when the smart alternator reduces its output.
Post #9:-
The smart altenators do not cut off the voltage when the battery is fully charged. The output from them gets reduce and its to a level in my case where its not sufficient to power the fridge or charge the leisure battery.
Cutting off the voltage would be a major problem for those with ATC.
Switching the lights on or any other load makes no difference in my case.
On my Qashqai I have a tell tale light that indicates the turn signals are working.
It doesn't mean any of the other lights are working but it's at least something,
I recall my first towbar installation in the '90s came with a beeper that sounded if the turn signals on the caravan where being activated.
I've just noticed that my PDU has a fuse labelled 'Car'. I think this may be for the permanent Pin 9 power so if I pulled this it would perhaps break the connection to charging the leisure battery ( or in my case discharging) and also prevent the fridge from being powered when towing - which I could live without.
Our previous Jeep bleeped when turn signals were activated, but not on the current Jeep.
The concern here is if the lights went faulty en route to a destination, you may not know of the issue. I had th lights go faulty many years ago once when towing a trailer caravan however in those days no such thing as a warning notification regarding trailers.
Maybe which is why i was wondering if there was any way to test it before it actually happened?
The "permanent" 12v supply doesn't have to be permanent ! On a VW Group car, there's likely to be a relay which only energises the circuit after a plug is inserted into the socket, with a delay of around 5 seconds.
As I suggested earlier. But you would need to watch that it did not cut off the ATC.
I always found that in older days with voltage sensitive relays in the boot for charging and fridge. Did work. but not all that effective. It is the modern sophisticated car electrics that cause the incompatibility.
I always installed my car electrics with oversized cable. (Like RogerL). I would run a 10mm run from the battery through to the boot to feed both relays. Getting through the bulkhead is very difficult. so I would put them through a hose pipe for protection and run them under the car.
These days I do not bother. The leisure battery gets plenty of power from the solar panels. The fridge may, or may not work effectively. But I would just put some frozen milk in it before setting off. As OC suggested.
John
Interesting. Mine is definitely permanent even when no key in the ignition.
I wonder how the VW knows when the plug is inserted.
Since I've been cleaning the van which means I can think about other things at the same time, it occurred to me that if the Pin9 permanent supply is supposed to be connected to the leisure battery for charging purposes then I should be able to measure it's voltage at the caravan connector without the car connected.
There is no voltage on Pin 9 of the caravan so there must be something else in the circuit preventing this appearing. I wonder if the habitation relay not only passes the switched 12v (pin10) to the fridge but also the permanent 12v (pin9) to the battery.
It's a shame the schematics of the van are very basic. I tried to get more detail from BCA, but they wouldn't release anything to me.
Here is some reading material. See https://caravanchronicles.com/2017/02/15/smart-alternators-how-they-affect-caravans-and-motorhomes/
and probably more relevant;
https://caravanchronicles.com/2017/04/25/getting-all-charged-up-part-1/
There are three parts for the above link.
https://caravanchronicles.com/2017/02/15/smart-alternators-how-they-affect-caravans-and-motorhomes/
and probably more relevant;
https://caravanchronicles.com/2017/04/25/getting-all-charged-up-part-1/
There are three parts for the above link.
https://caravanchronicles.com/2017/02/15/smart-alternators-how-they-affect-caravans-and-motorhomes/
I read somewhere a while ago that in most cases the vehicle 'knows' that a trailer is connected by the presence of the rear fog light or reversing lights.
My 2014 Santa Fe doesn't, but it does charge my caravan Battery and runs the fridge ok at 13 .9 volts. 🐿️Simples. 😃
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