Click>>>BOOM...yes Virginia, batteries can and do explode! NAC

quattro + 5 or 8 = fun thequattroking at
Wed Sep 3 00:34:13 EDT 2003

This just happened to me in my V8q.  WHAT A FRIGGEN MESS.  No more excide
batteries for me (3 rd one to explode in 3 different cars).  Only Douglas
batteries from now on.


Bay Area, CA

Audis, MBZs & a black sheep BMW.

PARTING:  1972 Mercedes Benz 280 SE 4.5

> From: Bernie Benz <b.benz at>
> Date: Tue, 02 Sep 2003 20:25:24 -0700
> To: Peter Schulz <peschulz at>
> Cc: audi-20v <audi20v at>, 200q20V mailing list
> <200q20v at>
> Subject: Re: Click>>>BOOM...yes Virginia, batteries can and do explode! NAC
> Very, very strange, Peter!
> Battery water is decomposed into H2 and O2 only when the battery is being
> overcharged, normal charging of a partially discharged battery does not
> cause this H2O breakdown.  Only a faulty regulator can cause this condition
> with a good battery.  If the battery had a shorted cell, a good regulator
> would overcharge the remaining good cells in attempting to establish the
> correct battery voltage.  The battery is toast, but have the regulator
> checked.
> In either case, the resultant mixture of H2 and O2 would be forced from the
> battery vents during and immediately after the overcharge condition.  This
> stoichiometric mixture discharged from the battery vents, with the motor
> running at a reasonable charging speed, will be immediately diluted to below
> the LEL (lower explosion limit) by under the hood air movement.  When the
> engine is stopped there may be a momentaary build up, but the source is
> eliminated when the engine is idling or stopped and further, the mixture is
> lighter than air.
> The individual vent hole in each cap is designed to be too small to allow
> flame propagation, and the Audi type vent tube is too long to allow similar
> flame propagation.  So IMO, unless some caps were inadverntly left off, and
> the required explosive mixture conditions established within the battery air
> space, and an ignition source established at the vent, there could be no
> explosition.  The only open ignition source might be the rotor to cap spark
> gap, but if an explosive mixture existed at that point the cap would have
> been removed.
>> From: Peter Schulz <peschulz at>
>> Date: Tue, 02 Sep 2003 13:43:48 -0400
>> To: 200q20v at, 20v <audi20v at>, s-car-list at
>> Subject: Click>>>BOOM...yes Virginia, batteries can and do explode! NAC
>> And I thought this only happened to other people...
>> Patient was a 1992 Infiniti G20 owned by a friend of my wife's.
>> She went to leave our house, turned the ignition key which was followed by a
>> loud BOOM and smoke from under the hood.
>> I opened the hood to find the vent caps missing from the battery, the top of
>> the case cracked open and the stench of sulphur.
>> If it had not been for the "over the case" battery clamp, the whole top would
>> surely have blown off.
>> The battery was a Nissan oem battery, After I liberally washed the area
>> around
>> the battery with baking soda and water, we were able to find a replacement at
>> a nearby Autozone...
>> I shudder to think what might have happened if this battery had been under
>> the
>> rear seat, as in one of my Avants.
> There is no ignition source at this location.
> Bernie
>> I assume what happened is that the water level was too low, and that the
>> turning of the ignition switch caused an internal short that ignited the
>> hydrogen?
>> More reason to periodically check the water level in you batteries.
>> -Peter
>> Peter Schulz
>> 1990 CQ (awaiting S2 3b engine transplant)
>> 1991 200 20v TQW indigo mica
>> 1991 200 20v TQW titanium grey
>> Chelmsford, MA USA
>> peter at
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