On Mon, 5 Jan 2009 19:03:02 -0800 (PST), "hr(bob) "
wrote:

On Jan 5, 7:26*pm, "John Keiser" wrote:
In my experience, the batteries last no more than 5 years. *If this is the
original battery, its time is likely up. *Test under load or with a
substitute and replace for $25 or so.

Unless you test the battery under load, you don't really know much of
anything. If it is too hard to connect the battery to the UPS when
the battery is out of the UPS unit, use an automobile back-up light or
something similar, but smaller than a headlight, and see if the
voltage really holds up under load.

I got tired of dealing with guesswork on batteries. So, I bought
myself a Hanukkah present:
West Mountain Radio CBA-II.
http://www.westmountainradio.com/CBA_ham.htm
About $150 including the optional thermal sensor. I've been running
discharge curves on various batteries in my collection. I'm mostly
interested in how various Lithium technologies operate, but have had
time to mess with some 12v 7A gel UPS batteries. There's a rather
obvious difference between a new battery and one that's been
continuously (over)charging inside the UPS. I plan to post graphs,
but I'm not sure of my current settings and methodology, so that will
need to wait. For example, I was having problems with Powerpole
connector losses when I read comments at:
http://www.westmountainradio.com/cbausers.htm
by Bob WX2NJ (at bottom of page). At the rated 1c (7A) load, the
connector resistance resulted in a premature cutoff point.

Anyway, the CBA II is far more accurate and entertaining battery
tester than timing a fading auto tail light.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558