On Sat, 30 Apr 2005 23:44:19 GMT, Gene Kearns
wrote:

On Sat, 30 Apr 2005 00:33:26 -0500, Richard J Kinch
wrote:

Perhaps I wasn't clear. Paralleling lead-acid batteries is done, but
its not a good idea. If series is possible then use series.

I don't find any merit in what you offer as fact.

I don't want to get into a citation war either, but short of a
religious faith in safe vs. unsafe battery practices it would be nice
to have a little science to back up one's words.

I, too, have seen the explosion (and thermal runaway) of batteries,
but I believe it made not a whit of difference whether the battery was
paralleled or in series.

If you have some sort of objective scientific explanation reaching
beyond having seen a car battery explode and consequently becoming
afraid of them.... I'd like to hear it.

The only thermal runaway I have ever personally witnessed was an
industrial application in which temperature extremes caused a
situation in which the charger overcompensated starting for a low
temp condition and continuing through a high temp condition. The temp
compensator circuit was faulty. That was the only situation I have
ever watched personally. I've worked on investigations of thermal
runaway, but they almost always were caused by this same condition -
the temp compensation was faulty. You see this type of condition with
BBU systems also. These were/are not your everyday run of the mill
lead acid starting or trolling batteries though. They were rapid
charge/discharge batteries which are not seen in daily applications
being special purpose.

To give Richard his do, there have been some reports of AGM batteries
having thermal failure as a result of inappropriate application.
These have all been misapplication of the AGM technology rather than a
fault in the system themselves. In one reported case, a garage
mechanic just slapped a rapid charger on an AGM battery and it went
kablooey. These seem to be few and far between however and mostly
related to RVs which somehow figures.

To get back to the main discussion point - in basic service, with lead
acid batteries parallel circuits are as safe as can be and unless
somebody is a complete and total idiot, almost impossible to screw up
or blow up due to the basic nature of the circuit itself.

Later,

Tom