Exploding battery

[homemoz]

Went to plug the battery onto my bike the other day....and bang!! Went off with a load pop, described by my wife as sounding like a gunshot. Luckily, the battery was in an alloy case, so no damage done. I had been charging the battery up as usual with no apparent problem before fitting it to the bike.

For the record, the battery is a 4 year old 24v 8amp NIMH which has been regularly charged and stored indoors. Does anyone have an idea what could have caused this? I always thought NIMH batteries were supposed to be safer. Had it gone off in the house & not been in an alloy case, could have been nasty. Now I make sure my other lithium is safely stored outdoors. Maybe there is a case for older lead acid technology after all.

 

[Deleted member 4366]

Sounds like a short circuit somewhere, which has either blown a fuse or vapourised a bit of wire, Where about was the pop - in or outside the battery?

 

[homemoz]

Sounds like a short circuit somewhere, which has either blown a fuse or vapourised a bit of wire, Where about was the pop - in or outside the battery?

It was a very loud pop - more like bang. My wife was in the house whilst I waa outside in the car port & said it sounded like gun fire. The bang was inside the battery & accompanied by a smell of burning. The seal on the battery case is very tight, so haven't taken it apart to have a look yet.

 

[morphix]

That sounds very nasty glad nobody was hurt. I very nearly lost my eyesight many years ago when a battery exploded on me. Having bits of battery pulled out of your eyeballs and then being blind for a week is no fun at all.

Are you able to say what make of battery it is or where you got it? Was it overcharged or anything?

 

[homemoz]

That sounds very nasty glad nobody was hurt. I very nearly lost my eyesight many years ago when a battery exploded on me. Having bits of battery pulled out of your eyeballs and then being blind for a week is no fun at all.

Are you able to say what make of battery it is or where you got it? Was it overcharged or anything?

I can't say what make of battery it was. The battery came with my Dahon from CH White & Son in 2007. The bikes they now sell look to be fitted with the 8fun kit, although I can't be certain of that without a closer look. The battery had lost quite a lot of capacity over the years and was really only used as a backup these days. I had it on the charger that morning, but only for a couple of hours & the charging light was still showing red. No indication that anything was wrong until connected to the bike.

Morphix's experience with an exploding battery sounds pretty horrific. Just glad this one had a protective case.

 

[flecc]

Any battery, indeed any current storage device has the potential for explosion, lead-acid batteries included.

Connect a large electrolytic capacitor the wrong way round (no don't!) and the explosion can be spectacular. One that was done to by someone years ago instantly redecorated their previously white room yellow. Luckily they'd just left the room when it blew.

 

[wurly]

I have had a battery pack get so hot it melted the solder on the connections. The wires fell off and it lost contact with the charger(luckily). Never got one to explode yet though.

http://www.pedelecs.co.uk/forum/electric-bicycles/3964-disaster-my-batterypack.html#post51286

Speaking of spectacular explosions, i used to work in a repair workshop and we had a contract for fixing supermarket scanners. They usually arrived with ballooned capacitors but some would have direct shorts. I would connect mine via a 100watt lamp. If there was a short the lamp illuminates, simple. One lad simply closed his eyes and switch on the power and waited to see what happens. On one occasion a high voltage varister burned itself out like a mini volcano...the whole process took about 5seconds with a smoke plume that rolled along the ceiling. How we all laughed as he wiped the debris from his face.