Nuevo leisure battery smoking

Hope someone might be able to help.  Have just taken van out to fuel up ready for our trip away tomorrow when the cab started filling up with smoke.  It seemed to be coming from under the seat.  Turned engine off but it started again when turned it on again.  When I checked it appears that a couple of the fuses were melting.  Any ideas what might have caused it.

What state was the leisure battery in before you started the engine? It's not necessarily the answer, but it's fairly common for someone to do an engine start with a flat or almost-flat leisure battery. The split charge relay operates as soon as the alternator produces output, and it connects the alternator and a fully-charged engine battery to a flat leisure battery. If you're lucky, the current flow is too great and the split charge circuit pops. If you're not, the current flow is just less than the fuse rating and it overheats all of the connections in the circuit, melting the fuse assembly and wiring.

The problem can be made worse if you have the fridge 12V element switched on - because that can add an extra 6-8A load into the equation.

Agreed with all Roopert says, I'd add that I'd advise removing the fuses (once they are cooled) and check the voltage of the LB. If it seems reasonable, then try charging it, disconnected from the vehicle with a separate charger. If that works try replacing the fuses with new ones and see what happens, ideally without driving it!

I had problem with fuse holder melting , it was a cheap factory fit one close to the engine battery think it was a 50 amp ,loose crimp connection caused the fuse holder to overheat and melt. Replaced with a quality  fuse holder  ,no further problems .

Thanks all.  I think the battery was charged up as we had only recently been away in it.  However, I think the 12v switch on the fridge was on so might have pulled extra through.  I cant replace the fuses as they have melted into the socket so it looks like a new fuse box is needed.   Looks like a trip to the garage.

Thanks for your suggestions

Just a thought.  Is there a way to light the gas fridge without the 12v switch working?

Our Tilly wrote:Just a thought.  Is there a way to light the gas fridge without the 12v switch working?

It's not clear which 12V switch you mean, but if you mean the 12V switch on the fridge (likely given the context) you don't need that on to light the gas - it's a completely separate circuit. It may vary from van to van, but typically you just need the main habitation 12V turned on to light the fridge gas. Once lit you can turn the habitation 12V off, but be warned that if you do, the fridge will not re-light if the flame blows out - this feature is present on some fridges but (I think) not all. Even on fridges without the feature there is no danger of leaks if it does blow out - they all have flame failure sensors.

Therein lies the problem.  We have no 12v to power the ignition as the fuses burnt out and the AA man disconnected the system.  The truma heater is ok as it lights by an ever ready battery but I assume the ignition on the fridge is via the 12v system, just wondered if there was another way.  No worries, its cold enough outside for he cool box to stay cool.

Thanks

If you're sure that the problem is not a failing leisure battery, and that the fridge being on was the sole cause of the problem, then you should be able to jerry-rig a temporary low-value fuse across the terminals of the melted fuse holder - the gas ignition should take very little current at all. It really does depend how much effort you would be prepared to put into a temporary fix until the wiring is repaired properly.

Thanks for that.  I think I might leave it until we are back home as we have no tools etc - a bit hopeless on the practical repair front.  As mentioned the AA man cut the live wires off on the battery so nothing can work.  It is quite cold where we are so I am sure nothing will perish.