Battery hot fizzing and smelly

[richardsnowstar]

I have a battery problem.
I have 2 domestic batteries and a 3rd engine start battery.
I had a Xantrex smart charger and it suddenly stopped working accompanied by an electrical burning smell and signs of burning on the fan exit vent.
I replaced it with a Sterling smart charger.
This appeared to work fine but after a while the engine battery was very hot, fizzing and smelling of sulphur.
The charger was still delivering the full amps even though it should have reduced to trickle charge by this time.
I have now disconnected the start battery and the charger is working as expected on just the domestic set. The current is reducing as the batteries are getting towards full charge.

Can anyone tell me why the start battery is getting so hot and fizzing?

Thanks.
Richard.

 

[nimbusgb]

Start battery is shot, probably why the first charger died.

Replace battery. Sounds like a plate or two have shorted out.

 

[Easticks28]

Start battery is shot, probably why the first charger died.

Replace battery. Sounds like a plate or two have shorted our.

+1

 

[SAMYL]

It's fecked.........

 

[Nigel-in-Oxford]

+1

+2

 

[TQA]

Be careful if it has been fizzing recently [ hours not days ].

The gases produced are oxygen and hydrogen and combined are explosive. Ventilate well before doing any work including disconnecting the battery.

As others have said it will almost certainly be a dead cell leading the charger to overcharge both batteries.