Some feedback on 12v

[Tram]

Some time ago, in Autumn 07 to be honest, I posted about my fridge not working on 12v from the car.

That was the last time we returned from a tour, the fridge had defrosted and when I re-connected found that the red light on the fridge was flashing and a relay was clicking in time with it in the caravan consumer unit.

The 'van went in for its service recently and I asked that they look at the 12v system. They found nothing wrong. I borrowed another car and tested it with that and confirmed that the 12v to the fridge was fine. The red light stayed on and steady.

Next step, phone the tow bar fitting people and arranged for them to have a look. The guy said it sounded like the summat-or-other was faulting so he lifted out a snakepit of wires from inside the boot side cavity and there were two boxes in with it. He fixed a meter to the 12S socket and tweaked an adjusting screw in the end of one box saying he had increased the delay in the box reacting to the caravan electrics, and to 'try that.'

To cut a long story short, it has worked. And the best bit? No bill, just a "come back if it doesn't work".

Now we can't wait for April and the start of our season.

 

[GrahamSouthBrum]

Sorry I never saw your origional posting, but I had that problem a few years ago.

The tow bar fitter showed me what to do if it happened again

 

[Tram]

Hi Graham, did he say exactly what to do? I just watched what he did and listened to what he said but he didn't tell me I could do it myself. I haven't go a meter if one is needed.

 

[rayc]

Tram, What he did was adjust the car fridge relay operating voltage. The relay is voltage sensing and operates when the engine is running and the alterrnator supply causes a rise in voltage. If the relay is set to operate at too high a voltage then the relay operates which feeds volts to the fridge, the fridge starts to draw curent which causes a drop in voltage so the relay un latches and the cycle carries on.

I adjust mine so it operates at tickover with the car headlights on.

 

[rayc]

Tram, What he did was adjust the car fridge relay operating voltage. The relay is voltage sensing and operates when the engine is running and the alterrnator supply causes a rise in voltage. If the relay is set to operate at too high a voltage then the relay operates which feeds volts to the fridge, the fridge starts to draw curent which causes a drop in voltage so the relay un latches and the cycle carries on.

I adjust mine so it operates at tickover with the car headlights on.

tram, perhaps I didn't explain that clearly. Connect the car to the van with engine at tickover with headlights on. Switch the fridge 12v on and adjust the realy until it operates e.g clicks and 12v lamp is on at the fridge.

[If your van is post 98 then you could switch the van internal lights on and when the relay operates they should go out. The reason is that the fridge supply also operates a relay in the van, which disconnects the van battery from the van electrics and feeds the charging voltage from the car to the battery].

 

[Tram]

Thanks for the info guys, any more trouble and I will have a go myself.