Leisure battery giving off an awful smell

[timski]

Hi All, I had posted previously about a possible leak from my LPG system, before I finally tracked the smell down to the leisure battery. I was surprised to find it really does smell like gas/rotten eggs. The battery was warm too. I've read that is a sign the battery is knackered and the smell is from the acid. I've disconnected the battery and made the live terminal safe. My question is, what would have caused it? I don't want to buy a new battery and for it to be knackered again. I've had two batteries go flat before as the kids have a habit of turning on lights and leaving them on, so I've been connecting my hookup to keep it topped up. I did that when I got back from camping on Thursday night. I also noticed is that the rocker switch for the three way fridge was still on the 12V battery setting. I must have forgotten to switch it off when I got back from camping on Thursday. So it's been on hookup and the fridge set to 12V. Would that have caused it or should a healthy battery of coped with that?

Thanks,
Tim.

[Mocki]

That’s a cooled battery , over charged . 
I don’t know what charger you have running off the mains , but if it’s a built in zig , that’ll be your issue , those things are cheap nasty unregulated rubbish ! 
as for the fridge being switched to 12v , that shouldn’t make any difference unless your fridge is wired incorrectly , it should only be ale to work on 12v when the engine is running . 

that battery is scrap , don’t attempt to use it now 

[AngeloEvs]

Conventional 3 way fridges take a higher current than is normally supplied by a typical ZIG charger of the type often fitted in T3's and other small campers of that era.  If your fridge 12v system is wired to the leisure battery then it would flatten the battery eventually.  Normally, the fridge is wired to the starter battery and most auto disconnect when the engine is switched off.   Might be an idea to check exactly how the fridge is currently wired,  the charger spec that your van has when on hook up and the type of battery (leisure deep discharge or starter).

[TONYT25T25]

Look for a suspicious wire coming from the positive side of the leisure battery to the back of the power supply to the fridge, I had one of those fitted by the previous owner, fortunately there was no leisure battery installed at the time just the wire to the positive terminal.  Unsure if it would have worked and safe but reading above comments think not.  Just to add a bit more believe when connected to 12v the thermostat is not a factor in controlling the temperature, the thermostat is only functionable when connected to mains, so if connected to 12v and the 12v switch is selected the fridge is on all the time, unless of course it is connected as mentioned above to the main battery and only selected via the control panel when the engine is running.

[Mocki]

Depends on the model of fridge , yes it’s true for most three way fridges that the 12v is non thermostat controlled, but not all ... either way it should not be able to use 12v when the engine isn’t running , and should never be connected to the leisure battery 

however I can across once fairly recently that was wired to the leisure battery via a VSR , and when the Mains battery charger for the leisure battery lifted the voltage up, the VSR triggered and powered up the fridge , drawing about twice what the mains charger was charging at .... VOltage sensing relays are bad news on multiple charge systems .... 

[timski]

It is a zig. And as far as I know the fridge only works off 12v when the van is driving.

If I get a new battery, how can I make sure it's well charged but not over charged?

I'm having a habitation service done soon, so I can get them to check all the wiring if ok.

Cheers,
Tim

[Mocki]

I doubt there is anything wrong with the wiring in relation to this 
f you are going to leave it plugged in when not in use , get a three stage intelligent charger fitted and disconnect the zigs charging ability . Or don’t leave it plugged in when not using it .

[timski]

I've read somewhere on here that you can rig up a relatively cheap meter from Maplin or suchlike that disconnects the battery when it falls below a certain voltage to avoid draining it. Is there something that works the same way if you're in danger of overcooking it, i.e. cuts it off once it's charged enough?
Thanks,
Tim.