Re: (ET) 12 volt batteries

["David Roden (Akron OH USA)" <roden ald net>]

On 8 Jan 2002 at 14:44, Jim Coate wrote:

> I don't think hydrogen is produced
> during use, but rather only during charging (and only the final phase at
> that)?

Correct.  Most likely a weak or dead cell was reversed under the 
relatively 
high current draw, which was more sustained than starting a car.  

You're also right that reversing a cell can generate hydrogen which might 
be 
touched off by a spark.  

Another possible scenario: a reversed cell under heavy current draw can 
produce boiling electrolyte.  If the battery wasn't properly vented, steam 
could 
have caused the explosion.

There's no reason that 12 volt starting batteries would be inherently 
dangerous for high current service.  They can produce a few thousand amps 
for tens of seconds.  Before the advent of high-current AGM deep cycle 
batteries, the EV drag racers used to use starting batteries.  They only 
got a 
few cycles from them, but they were pretty cheap.

David Roden
Akron OH USA