Hi - wondering if anyone can point me in the right direction with this one.
I have an APC BackUPS-RS 500 and it has recently been having issues. About
three weeks ago it suddenly started giving errors on the front panel and I
found that the battery had died (down to about 6v from the usual 13.8v).

I couldn't get the battery recharged at all, so I replaced the battery and
the UPS worked ok again. Then after a few days, I got the same problem
again. This time I was able to fully recharge the new battery, put it back
into the UPS and monitor it. The logs show that the battery is gradually
being drained although it has never gone onto a battery condition (ie not
lost mains power).

Does anyone have any ideas where I might start to look in repairing this?
I've found that I don't use the UPS that much since they upgraded our local
mains power infrastructure, but if I can get it working again without
having to buy new one that would be great.

I don't really know much about how these things work, other than they have a
battery and an inverter circuit. Any help would be appreciated.

Thanks