This is not really Hybrid related, but it is good info for anyone to know.

I was an auto mechanic for years so I knew this, but a lot of people may not. One of my neighbors was replacing the battery in his car yesterday & accidentally grounded the positive cable with his wrench causing a spark.

The spark caused the vapor emitting from the top of the battery to explode rather violently. The battery literally disintegrated, all that was left was a small corner hanging from the end of the battery cable.

A piece if shrapnel hit him in the forehead & he had 18 stitches to close the wound.............

~John

 

I am very sorry to read about your neighbor.

This is a good example as to why one ALWAYS connects the positive terminal first when installing a battery, and disconnects the negative terminal first when removing a battery.

By doing this, the chassis and body of the vehicle is never, ever, connected to the negative terminal of the battery, while one is using a wrench on the positive terminal.

 

And as a further caution note that the battery is filled with acid, which sprays everywhere when the battery explodes. Particularly nasty if it gets in your eyes.

Jump starting a vehicle can trigger this explosion if the last connection is made to the battery post instead of a part of the chassis away from the hydrogen fumes that surround the battery.

 

Yea, I forgot to mention that part. He got acid all over his chest & a few drops on his face but it wasn't real severe. He was pretty lucky really, he could have lost an eye (or worse)

~John

 

Good advice. This was just the discussion recently on another thread about how to disconnect the battery if left unattended all summer.

While I understand the chemistry involved, the amount of hydrogen produced in any given moment is tiny, and to ignite and explode, just the right air/fuel mixture must be obtained. How this happens by chance, at the moment of spark is truly, one in 1 million, however, 100 million batteries are changed each year, so perhaps 100 injuries will occur.

-John

 

The danger is greatest when the battery has just gone through a heavy recharge cycle, like being on a battery charger. I personally blew one up while taking it off a charger because I did not unplug the charger before taking off the battery clamps. The risk is real enough to err on the side of caution.

 

Agreed. I was trying to say 100 injuries was a lot, and 100 too many.
I wasn't trying to minimize the danger by any means.
-John

 

I had this happen to me when I was a kid, I shorted a battery with a long screwdriver, that was on charge in my dad's workshop area. I was leaning over it when it exploded, and gave me a bloody nose. Never again...

 

I always make sure I have plenty of ventilation.
With a breeze to blow any hydrogen gas away, you are pretty safe.
( Still try not to short the battery with a screwdriver! )