About to start some home renovations which involve the kitchen being demolished, so I’ve put the caravan on the drive to serve as a temporary kitchen/dining area. It’s been a while since I used it and I can’t for the life of me work out how to get the 12v system working.

It’s connected to 240v hook-up via the garage power sockets, and all the plug sockets in the van work, as well as the fridge when set to 240v, and the RCD trip button works. Nothing 12v though, no water pump, no lights, no extractor fan.

I’ve checked with a multimeter and there is 13.7v across the battery terminals with the PSU/charger on, which I think indicates that it’s receiving a charge. The PSU/charger 12v terminals also read ~13.6v with the multimeter.

The 12v Car/Off/Van switch panel gauge reads zero/red, but the car stereo the previous owner fitted works. This has been spliced into the 12v from the PSU though, so bypasses the Car/Off/Van switch panel. With the multimeter on the terminals at the back of the 12v switch, I get either 0v, 0.4v or 4.5v depending which way it is switched, so it’s doing something (although I’d expect at least one of the readings to be in the 12v range. The needle never moves from zero/red on the battery charge gauge.

I’ve searched high and low to see if there’s a main 12v isolation switch that’s in the off position, but can’t find anything. So I’m stumped.

Anyone got any ideas what the issue could be?

Fusebox?

What conditions the battery in ?

Not quite sure what you mean by ‘PSU’ but that could just be my ignorance.

If you connect the caravan to the car’s tow-bar power socket, does that provide 12V to the fridge etc.. ?

Also, I seem to recall a similar situation whereby it wasn’t possible to receive a 12V supply when electric hookup was being used, almost as if it’s ‘saving’ the battery while it’s charging….

We can’t run both on our camper. We can run gas, electric and diesel or gas, 12v and diesel but not 240v and 12v together

My camper won’t run the 12v direct from the panel has to go through the leisure battery first and draw from their for the fused 12v side

Only found that out when i unplugged the battery one day.

So if my battery was shagged then I’d get a crap reading.

Tracey are your lights 12v and 240 then ?

The only time out 12v kit wouldn’t work is when I removed the battery due to it being borked and giving of a sulphur type smell.

I had assumed that everything in the van would operate as it was on electric hook up but the 12v stuff still needed the battery in situ.

If you’re on hook up and your battery is connected, might be worth wiggling the terminals or wires connecting to the battery.

No idea, we have two lots of sockets 240v and 12v at the side of each other and when we plug in to the mains the 12v ones stop working. I assume the other stuff has some kind of converter. All the lights are leds.

Most of the time we just run of the leisure battery which is kept topped up with the solar panels on the roof. Only stop on campsites when we have to.

Fusebox?

All fuses look OK, and zero resistance across them with the multimeter. There’s only a voltage across the top 25A fuse though, again ~13.6v.

Not quite sure what you mean by ‘PSU’

Just the tranformer/converter/charger thing that runs off the 240v hook-up. No idea what its technical name is. It’s a Euro Charger 1014, if that helps.

Not checked leisure battery without it being connected to the charger yet, but the owners manual says that if running on a hook-up, the 12v transformer/charger should power the lights with or without a battery in place.

I used the van last in 2015 when I was contracting down in Cumbria. I don’t think I’m doing anything different to last time – 240v hook-up, 12v switch set to “caravan” – but it just isn’t working this time. All the lights, water pump etc. are 12v only though. Can’t see what the point would be of a hook-up if you had to sit in the dark when plugged in to the mains.

Battery out tomorrow to see what’s happening. It’s the fact the car stereo thing works that’s confusing me. There’s 12v somewhere in the system.

What make of caravan is it? That would be more helpful.

We have fights with my folks’ Bailey all the time as the switch panel is such a faff. That said its usually getting it to run on mains that is the issue.

You should, however, have a panel that controls everything. Water should be set to ‘run’, 12V master switch iirc set on, and your voltmeter will have a push button to operate. The fridge needs to be set to the right position locally, it won’t automatically switch over.

What make of caravan is it? That would be more helpful.

We have fights with my folks’ Bailey all the time as the switch panel is such a faff. That said its usually getting it to run on mains that is the issue.

You should, however, have a panel that controls everything. Water should be set to ‘run’, 12V lights on, 12V master switch iirc set on, and your voltmeter will have a push button to operate. The fridge needs to be set to the right position locally, it won’t automatically switch over.

Bit more info now I’ve had a chance to look at it. The battery is out, needed a charge but nothing too amiss.

The 12v system from the converter/charger is still operating, going on the fact that the car stereo still works even though the battery is out. Roughly 13.8v across the +ve/-ve terminals. I’ve followed the cable from the converter to the 12v control panel and I’m only getting 1.5v there, so I think that’s the problem. What would cause such a voltage drop?

What make of caravan is it? That would be more helpful.

It’s a Super Sprite Continental 500. Old, but apart from the electrical issues it’s in excellent nick.

Is the water pump shorting out ? Trying to think what’s the biggest drain on the 12v, my kids leaving bloody taps running flats our battery if off hook up.

So, while it’s plugged into 230VAC, is there 12-14V across the terminals of the battery? i.e. It would be charged if it were there?
Sorry but there’s lots of stuff above & I lost track of what was/wasn’t working & how it’s wired.

Yeah. When is plugged in to the mains there is ~13v across the 12v converter/charger unit, whether the battery is there or not. There is a car stereo spliced in to the 12v main cable before it goes to the fuse box, which is working, but nothing else 12v is working. I’ve traced the 12v feed from the converter/charger to the main 12v control panel (car/off/van switch thing) and I’m only getting ~1.5v there.

All fuses look OK, and zero resistance across them with the multimeter. There’s only a voltage across the top 25A fuse though, again ~13.6v.

If there’s a voltage across a fuse then it has blown (or the fuse holder is corroded, etc. causing a bad connection).

Ah, I think this is my electrical incompetence showing. I meant with the multimeter earthed I get 13v either side of the 25A fuse, showing (i think) that fuse is fine

Ahh… it’s OK then 🙂

Did you get any closer to solving this problem? I wondered if you had poor wiring between 12v converter -> control panel, or possibly a knackered control switch/button on there?

Ah, yes. I ended up running new cable from the converter to the control panel, inside the van this time. Everything seems to work fine now and the caravan hasn’t burnt to the ground yet.

Couldn’t work out exactly where in the original wiring the problem was, and it was part of a large wiring loom that goes through the floor and along the underside of the chassis before coming back in and up to the control panel – could have been damaged by road debris maybe. There was no main switch, as far as I can see, so hopefully I’ve not bypassed some safety-critical part of the electrics…

Mice ?