Hymer S700 battery compartment fire

[Greenvangirl]

Our twin leisure batteries were not charging so I don’t know if there might be a connection…? We had got 25km south of Dieppe when we smelt warm electrics. Just looking for a place to pull over when we started to fill up with smoke. We stopped on roadside (luckily it was midnight so not busy). We saw the smoke and a scary orange glow coming from the cupboard above the leisure batteries. Thank God for the fire extinguisher!
The end of one battery was melted with acid dripping down to the road.
We’re now wondering how it started. Possibly the cupboard floor/battery over was dislodged so pushing wires together?
Anyone had a similar experience or any advice on cause?
Also wondering whether to replace both or to have one bigger one……

Thanks from newbies Jo & Rob

 

[DelViv]

Scary !!!! Glad you are ok and managed to stop it getting worse. Generally the consensus is to have a matching pair of leisure batteries so I would opt for a new pair. Saying that, I am still a relative newbie and have got most of my knowledge off here. You have certainly come to the right place for advice. I would also join up. I have not regretted it and I am sure you wont either.

 

[autorouter]

We’re now wondering how it started. Possibly the cupboard floor/battery over was dislodged so pushing wires together?
Anyone had a similar experience or any advice on cause?
Also wondering whether to replace both or to have one bigger one……

A battery fire like that is very rare, so the cause must be unusual too. If the positive and negative terminals of a big battery like that are 'shorted' with a bar of metal, a huge current can flow, and the bar can heat up to glowing red or worse.

The negative of the battery will normally be connected to the metal chassis, and this will be connected to any metalwork throughout the MH. If for some reason the positive touches the metal chassis, or anything connected to it, then it becomes a short circuit. Normally there is a fuse in the positive very close to the battery, which will blow and stop the short circuit. But if somehow the short happens before the fuse, there's no protection. Maybe the bar holding the battery down has somehow moved, or some other metal object got lodged in the wrong place.

As for battery size, the problem is simply the size and weight of the battery. A 100Ah battery is about as much as the average motor mechanic would want to lift into a confined space. If you can handle a 200Ah battery, OK, it may look fine in the online photo, but don't underestimate its weight.

 

[DavidG58]

I would suspect some ‘additional’ wiring is more likely to be to blame

If you had a glow from the cupboard I think you might need more than a new battery

 

[Just smiffy]

Welcome….

With an end result like that you really need to get professional advice before putting any batteries back in, you really need to find the cause… if you are not educated in electrics get someone who is…

^{_{Subscribers  do not see these advertisements}}

 

[Greenvangirl]

Scary !!!! Glad you are ok and managed to stop it getting worse. Generally the consensus is to have a matching pair of leisure batteries so I would opt for a new pair. Saying that, I am still a relative newbie and have got most of my knowledge off here. You have certainly come to the right place for advice. I would also join up. I have not regretted it and I am sure you wont either.

Thank you. Yes…I would definitely recommend a fire extinguisher to all as a must-have!

 

[Greenvangirl]

Welcome….

With an end result like that you really need to get professional advice before putting any batteries back in, you really need to find the cause… if you are not educated in electrics get someone who is…

Thank you
The insurance co are going to investigate soon I hope. We can’t do a lot til they’ve had a look.

 

[Greenvangirl]

A battery fire like that is very rare, so the cause must be unusual too. If the positive and negative terminals of a big battery like that are 'shorted' with a bar of metal, a huge current can flow, and the bar can heat up to glowing red or worse.

The negative of the battery will normally be connected to the metal chassis, and this will be connected to any metalwork throughout the MH. If for some reason the positive touches the metal chassis, or anything connected to it, then it becomes a short circuit. Normally there is a fuse in the positive very close to the battery, which will blow and stop the short circuit. But if somehow the short happens before the fuse, there's no protection. Maybe the bar holding the battery down has somehow moved, or some other metal object got lodged in the wrong place.

As for battery size, the problem is simply the size and weight of the battery. A 100Ah battery is about as much as the average motor mechanic would want to lift into a confined space. If you can handle a 200Ah battery, OK, it may look fine in the online photo, but don't underestimate its weight.

Several good points there thank you…

 

[pelican]

Several good points there thank you…

Don't use or fit batterys until a qualified auto electrician has inspected and given the OK.