12 volt system query

Hi Everyone,
Hope you can help. Should the 12v lights work when the 240v hook up is connected and the 12v system is switched off?
Thanks

I would say 'no'.

Both systems are separate, apart from the 240 charging the 12v battery through the zig unit charger.

On our Clubman, we have a 12v switch on the zig control panel, and another at the bottom front edge of the wine cabinet cupboardmabob. The bottom one is so you can turn it all off without getting out of bed I guess.

You don't want the 240 working the 12v for sure, the cabling isn't up to that, and if it is you'll either get a shock, or a fire. Probably both.

I'm thinking you have a fault with your 12v switch, it's maybe not creating and breaking the contacts as it should. Do the 12v lights stay on even if you're not using 240?

Thanks Peatlander,
That’s really helpful. On the Topaz the 12v lights only work when the 12v switch on the zig unit is on, with or without the hook up connected. So, that’s as it should be?
On the battery charger, I’ve never seen the battery charger light come on in the zig unit. Should it?
Why I ask all this is because we had an experience earlier this month in France when we were hooked up, 12v system on and after a few days I went to start the van and the main battery was dead. No dashboard lights etc with the ignition on. 12v lights out too. Used a jump pack on the main battery and the van started immediately, and the 12v lights came on too. Just trying to understand why.
Thanks again.

Aha.

Ok....you have the zig 'switch' unit, with the guage for water, and switches etc..... there is another part, which is the charger. On ours it's under the passenger seat, not sure where yours will be, but it's a box maybe 6" square, 4" tall. It has a switch on the front so you can turn it off, presumably so you can stop it overcharging when you're plugged in for ages and not using the 12v? So have a look for that, check it's switched on. I did have a van once with the battery charger on the back of the switch panel, but it was a huge thing....

Another thing to look for are the fuses in the engine bay associated with the split charge system. If your leisure battery is past its best, then the surge from the alternator as it tries to top up the LB blows the fuse.

Interesting that your lights came on with the engine running...mine don't. I guess that's something to do with the split charge too...never really known. Sometimes I forget to switch them off, and then park up, shut down and the lights come on. Old age don't come alone you know!

Thanks Peatlander for that tip. I had a look around the van and found a switch above the water heater switch and beside the trip switches. I’ve never switched it on so that maybe the battery charger switch. I’ll put the hook up on and switch it on.
All the fuses in the engine bay are fine. I checked those first when we lost the 12v system, and they were all good.
Know exactly what you mean about old age though!

There are some handy manuals on this page

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There's a topaz one there, but for some reason the page for the wiring diagram says Talbot. Odd...

Might be some useful info there, could be some clues in the manual if you don't have one already. I think your fitted 'zig unit' is different to ours in looks, but probably the same in operation.

I have recently swapped all the fitted strip lights and the little halogen spotlights out for 12v led ones. Used a lot less power, and are a lot brighter too. Makes the battery last longer.

I had the control panel for the zig unit out a while back...kinda scary how much cable there is behind there. Spaghetti junction! Not a lot of room either.

put the hook up on and switched on the “unused” switch and the battery charging indicator light came on. First time I have ever seen it! So thanks very much for your advice! I had the zig unit out during the week so know what you mean about the mass of wiring! Sounds like a good idea to switch to led bulbs and will look into that.
Now if I can only get the toilet flush to work……..but I will make that a separate post! Thanks again.

Ooooh! We likes it when a plan comes together! Glad you got that sorted!

Yes, all sorted now and thanks again. Thanks also for that link, some really good stuff in there, really helpful.