On Sat, 21 Feb 2009 19:20:59 -0000, "Peter Hucker" wrote:

On Sat, 21 Feb 2009 02:48:54 -0000, rebel wrote:

On Fri, 20 Feb 2009 20:32:01 -0000, "Peter Hucker" wrote:

On Fri, 20 Feb 2009 03:30:03 -0000, Warren Post wrote:

On Tue, 17 Feb 2009 19:41:26 +0000, Peter Hucker wrote:

Is this a sealed lead acid? I've never seen one of those swell.

Yes, it is. It is so swollen it was quite a challenge to remove it from
the UPS.

I wasn't aware those type of batteries swelled up under corect usage. Maybe the UPS is faulty and overcharging it?

The main cause of small (home and SOHO) UPS failure is barttery failure. The
main cause of battery failure in small (home and SOHO) UPS is overcharge.

(They nearly all overcharge.)

The only failure I've seen in small and large UPSs is a drastically reduced battery capacity.

I'd suspect that is due to electrolyte drying as a result of ... overcharging.

Normally a UPS sits there being with its battery being slowly baked while the AC
supply is present. UPS failures become apparent to *most* home/SOHO users when
the AC fails as they do not have a testing regime in place.

Depending what you mean by "drastically reduced battery capacity" you may have
seen it a bit sooner than most. But drying electrolyte is the most common
capacity reduction mechanism, accompanied at later stages by the characteristic
case swelling and often splitting.