I have witnessed two such explosions in the past 50 years or so.  The first
was when I was quite young.  I was disconnecting a battery charger in our
family's used car lot.  All the caps blew off, but the battery remained
intact.
  The second is worth noting because there was no charging involved, just a
heavy discharge.  A large coach type bus was not starting and the battery
was getting run down.  An inexperienced mechanic was poking at the terminal
with a screw driver.  The explosion blew the top off the large square
battery.  The top went up a couple of inches and settled back down.

Larry A.

On Sat, May 2, 2015 at 5:11 PM, Jim Felder <jim.felder@gmail.com> wrote:

> I have no idea what happened, but if anyone wants pictures of an exploded
> battery I have them. I sprayed everything off and then distributed a box of
> baking soda on the mess. This is a diesel, so I was standing outside the
> driver door and the battery was 15 feet away in the back. I could see the
> smoke/mist and smell the strong fumes, so I vacated the area until things
> calmed down. I never got any acid on me.
>
> This was a no-brand, mexican made battery that AAA put in my son in law's
> volvo a three or four years ago. It's been sitting around doing nothing
> since they junked the car a year ago.
>
> Jim
>
> On Sat, May 2, 2015 at 3:47 PM, Jeff Schwaia <vw.doka@gmail.com> wrote:
>
> > This will also happen if you reverse the leads on a battery charger.  Saw
> > it
> > happen once on a freshly painted car at the body shop located behind the
> > shop I was working at.  Lot flunky hooked up the leads backwards and blew
> > up
> > the battery when he plugged in the charger.  Shop owner wasn't too
> happy...
> > can you say "re-prep and re-spray"?
> >
> > Cheers,
> >
> > Jeff
> >
> > -----Original Message-----
> > From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
> Of
> > Dick Wong
> > Sent: Saturday, May 02, 2015 12:58 PM
> > To: vanagon@GERRY.VANAGON.COM
> > Subject: Re: Boom! Started my day with a little nitric acid
> >
> > When charging a car battery, the outgas is oxygen and hydrogen.  This is
> an
> > explosive combination.  When the starter was engaged, a spark from
> anything
> > nearby (loose battery terminal, relay, starter brushes) could have
> ignited
> > the gas.  That's why charger instructions tell you disconnect the charger
> > power or switch it off, before removing the leads at the battery.
> >
> > Many years ago, I had hooked up a dead battery to a charger in the shop.
> > My
> > dad went in to the shop and turned on the bench grinder. As soon as he
> > touched the metal to the grinder, kaboom!, the battery exploded.  Luckily
> > he
> > didn't get acid in his eyes and there was a water hose nearby where he
> > quickly washed himself down.  Other than ringing ears, he was okay.
> >
> > Cannot be too careful when working with batteries.
> >
> > -Dick Wong-
> > 78 Scirocco
> > Original Owner
> > 87 Vanagon Syncro 2.5 (Blaze)
> > Third Owner
> > 12 Golf TDI
> > Original Co-Owner
> >
> >
> >
> > -----Original Message-----
> > From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
> Of
> > Eric Caron
> > Sent: Saturday, May 02, 2015 11:56 AM
> > To: vanagon@GERRY.VANAGON.COM
> > Subject: Re: Boom! Started my day with a little nitric acid
> >
> > Jim,
> >
> >         Please give us a update.  And, why do you think this happened?
> >
> > I once knelt on the back seat of a 74 super beetle and had a similar
> > experience.  covering one of those terminals was a lesson I learned the
> > hard
> > way at age 18.
> >
> > funny thing is the car started and we drove that way to sears to get a
> new
> > battery!  that is we did once the smoke cleared.
> >
> >
> > Eric Caron
> > 85 GL Auto Westfalia
> >
> >
> > > On May 2, 2015, at 2:40 PM, Stuart MacMillan <stuartmacm@GMAIL.COM>
> > wrote:
> > >
> > > Ouch!  Sulfuric acid does not evaporate!  The water it's mixed with
> > > does,
> > leaving concentrated sulfuric acid behind, which will do incredible
> damage
> > to you and the van.
> > >
> > > Suit up in old clothes, wear a face mask and rubber gloves, remove
> > > what's
> > left of the battery, and wash everything down with a solution of baking
> > soda
> > to neutralize the acid.  Then take a shower and wash the old clothes, or
> > they will be full of holes the next time you see them.
> > >
> > > Stuart
> > >
> > >
> > > -----Original Message-----
> > > From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On
> > > Behalf Of
> > Jim Felder
> > > Sent: Saturday, May 02, 2015 9:27 AM
> > > To: vanagon@GERRY.VANAGON.COM
> > > Subject: Boom! Started my day with a little nitric acid
> > >
> > > Charged the battery overnight in Fifty Shades of Brown in anticipation
> > > of
> > getting the pump primed this weekend. When I hit the key it sounded like
> a
> > > 12 gauge shotgun in the back. It literally blew the top off the
> > > battery
> > and sent acid all over the place. Glad I was at the switch and not back
> > there.
> > >
> > > Jim
> > -----
> > No virus found in this message.
> > Checked by AVG - www.avg.com
> > Version: 2015.0.5941 / Virus Database: 4339/9677 - Release Date: 05/02/15
> >
>