Technical Exploding Battery

[youngjohnnie]

I have a bessicar motorhome on a Fiat Ducato chasis. Just put it in for an engine service.
While it was in garage noticed plastic and breather tube on driveway. Took them to the garage and they investigated and found the battery (the vehicle battery) had exploded.
What could have caused this

 

[Deefordog]

Overcharged or ****ed battery? One or more plates may have given up - what's the age of the battery?


Never seen a pic of an exploded battery, care to post one?

 

[youngjohnnie]

Battery is 5 years old. The garage is checking the alternator for overcharging.
Dont have a pic but it destroyed battery box.

 

[toyogran]

Some bright 'spark' at the garage hasn't shorted the battery with a spanner or similar accidentally?
I inadvertently shorted a Morris 1000 battery once with a spanner. The spanner arc welded itself to the battery and earth and blew the battery up bursting the case and spewing acid everywhere.
Moral of story disconnect negative before playing with spanners!

 

[errolmorris]

Batteries do not spontaneously explode...okay, I have heard horror stories, but in all my years I have never seen this happen without human intervention.
I have been in the trade for over 40 years.
Youngjohnnie has probably nailed it.
The workshop would very likely be down one staff member at the moment. It would never do to have someone around with acid burns to their hands or face would it?
I have no idea of the laws over there covering this, but I would be asking for the repairs at their expense anyway.

 

[youngjohnnie]

No. Wasnt the garage. Evidence on my own drive of the battery box pieces and the breather tube.

 

[corcai]

Im guessing you plugged it in at some stage over the winter. Even if your charger isnt overcharging when a plate shorts the voltage on the others is above the gassing voltage producing explosive gasses. I witnessed one exploding after a technician had left it on Turbo charge overnight the casing practically vanished in the explosion he won't make that mistake again.

 

[oigle]

I had a deep cycle battery go very close to exploding in a caravan. A cell had gone down and the charger kept trying to charge it. It was so hot that, even after being turned off for an hour, I couldn't touch it. I was made aware of the problem by smell. First thought it was LPG but eventually found it - so close to a major blowup....


Ian.

 

[Crossingkeeper]

Interesting thread.....I'm wondering how it was even possible to start the van to drive it to the garage?

Unless the battery exploded when the starter motor was drawing current....

 

[youngjohnnie]

Yes very interesting about being able to drive it to the garage.
I had the motorhome plugged in to the mains and I assume that it also tricke charges the vehicle battery. (can anybody confirm that).
It started ok and I parked it at the garage overnight. They did the service next day and there was no word of them having problem starting the motorhome.
It was then parked up while waiting for the new battery box. The battery box had only been examined from the outside while up on the ramp.
It wouldnt start when they tried to take it in to fit the box and had to jump start it.
It was when they opened up the battery box that the exploded battery was discovered.

 

[rayc]

They did all that and didn't think of looking inside the battery box once they discovered it was damaged? what did they think had damaged the box?

 

[CDK]

Here is a picture of an original Ducato battery that blew its top and caused a lot of collateral damage. The cause was a sophisticated MPPT solar regulator that on a sunny day suddenly decided 18V was the best charging voltage.

 

[g8rpi]

One overcharge failure mode that causes a literal explosion is out-gassing and overheating. The gasses are hydrogen and oxyge in an explosive ratio. Overheating causes expansion and softening of the insulators between plates. The results in a short circuit , spark and ignition of the gasses.
Always be very careful when disconnectiong a battery that has been on charge, either an external charger or normal vehicle use. Even a tiny spark (technically the limit is about 200uJ which for a 12V battery is less than 0.02 amps for 1/1000 of a second, this level can be caused by static). can cause igntion and the space inside the battery is full of an explosive gas mixture. It's more likely to explode than a petrol container because the mixture in the "air" space in a petrol container is normally too rich to explode. Many years ago a work mate had a lucky escape. He had put a mobile battery pack with lorry sized batteries on charge, came back later and switched off the charger, went for a cup of tea (to allow gas to dissipate), came back and as he removed the charger connector a battery exploded. Someone had "thoughtfully" turned the charger back on. He was lucky, as a glasses wearer he got no acid in his eyes but had a circular scar on his forehead where a vent cap hit him.

Robert G8RPI

 

[Deefordog]

So no starting problems until the garage tried to jump start the vehicle - hmmmmmmmmmm

IIRC, the cab battery on your motorhome isn't charged from the on-board hab charger. That's why many owners fit solar panels to trickle charge the leisure batteries AND the cab battery. A quick question on the Swift Talk forum would confirm the charging regime and what does what.

 

[youngjohnnie]

The battery had exploded long before the jump start by the garage.
Bits of the battery box and the battery breather tube were on my drive when I took it to the garage.

 

[varesecrazy]

The battery had exploded long before the jump start by the garage.
Bits of the battery box and the battery breather tube were on my drive when I took it to the garage.

I'd considered it feasible that it COULD have cracked the battery casing in extreme cold..,
however that scenario would mean the battery would have lost fluid...probably damaging cells , and would therefore NOT crank the starter..,

it's an odd one..,
Charlie