On Fri, 02 Sep 2005 10:45:44 -0500 Ryan Underwood
wrote:

Jim Adney writes:

Interesting. Across one cell, it drops from 5.4V to 2.8V, when initially
plugged in, then after the UPS chirps and dies, it gradually rises again. Not
sure what's going on here.

That makes me think that the cells are in there backwards.

The cells are in the packs backwards, or the packs are in the UPS backwards? I
don't see how the packs could be backwards, they are hooked up exactly as the
old ones came out. The +/- leads are too short to reach to the wrong
respective terminals anyway.

The impression I got was that the charger was coming on and driving
current the wrong way thru the batteries, but on second thought, maybe
what you're seeing is just due to some load that the UPS is drawing
from the batteries for a brief moment, until it decides that there's
not enough voltage there for it to work.

I'd take the batteries out of there and just try charging them very
slowly on an ordinary trickle charger. A small 6 or 12V bulb in series
will help limit the current, which is something you really want to do
if you want the best odds of salvaging cells left standing for a long
time.

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Jim Adney
Madison, WI 53711 USA
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