Split charge relay question

[Len_Cuff]

Finally got round to fitting the second (12S) socket today using the NP107 relay supplied. All looked fine but when I connect the socket to the caravan, the relay constantly switches on and off at about 2 second intervals? Is this right? I assumed that once the car voltage had reached a set level, the relay would switch on and stay on until the voltage dropped? Looking at the fridge while it's connected I see the 12V light switching on and off all the time. Have I got a duff relay unit?

 

[Len_Cuff]

Forgot to add, it does this irrespective of how fast the engine is running.

 

[Jaydug]

What section of wire have you used to power the relay? From your description it sounds as though the wiring is too thin and it's suffering from voltage drop. The wire should be taken directly from the battery or alternator and should not be less than 2.5mmsq.

 

[Len_Cuff]

I thought that at first but I'm using the cable already there for this purpose. Vauxhall put a cable in place which terminates in the boot and is fed from a 25A fuse.

I'll try hoking a meter up to the feed cable and see what it doing but it's definitely thick enough cable.

 

[xtrailman]

Check for a bad connection, possibly the earth/chassis connection.

When you check the relay voltage, ensure you measure between live and return on the relay connection. Expect around 14v, with the engine running.

 

[Bryan_374360331]

We had that with our old Golf + Ranger. We just put up with it until we changed them.

Sorry, no help, but you are not alone!

Bry

 

[Tram]

Hi Len,

I had exactly this problem two years ago and I still haven't resolved it. I have checked everything and had the car back to the tow bar fitters. They have adjusted it but the clicking just got faster. The clicking comes from both the cars relay and the one in the caravan consumer unit. I sometimes think the relays are fighting each other.

You don't own a Galaxy by any chance do you?

 

[BigAl1]

Len.

You don't say what caravan you have got or more importantly what fridge. Is it a twin fridge / freezer. I suspect that it is.

I had the same grief, what I did was to chuck away the voltage sensing relay and fit one that is connected to an ignition supply (but not live when cranking).

Al

 

[Len_Cuff]

The car is a Vectra 2.0DTi and the fridge is just the standard fridge fitted. I'll dig out the model number later but it's nothing special. Just annoying that it isn't doing what I expected it to do but of course it could well be the relay itself ? The van by the way is an ABI Yorkshire Rose 520EJ.

 

[Jaydug]

Some relays besides having a factory set voltage trip, also have a customer enabled adjustment. Have a look at yours.

 

[Len_Cuff]

Just dug the relay back out of it's hidy hole and there appears to be an adjuster through a small hole in the top! Assume you connect it up and then adjust until the relay stays on?

 

[Jaydug]

That sound about right. Also if they are in a confined space the heat makes them malfunction. They need ventilation.

 

[Len_Cuff]

Many thanks, got it sorted. Just needed a small tweak on the adjuster. Now it comes on a minute or so after the engine's started once the battery voltage has risen a bit.