From other posts it looks like APC UPSes eat the lead acid batteries
that are in them over a short period of time.

I own an old APC SU2200NET SmartUPS. It has 4 - 12V 17Ah lead acid
batteries conneted in series which called an RBC11.

Well my UPS stopped working one day and when I opened the battery bay
the 4 lead acid batteries had wollen to take up all the space in the
battery bay. I had to drill all the rivets and take apart the steel
frame that made up the bay that the lead acid batteries were in to get
the 4 swollen lead acid batteries our of the UPS.

After some reseach on the Usenet newsgroups I found that this was in
fact a VERY common problem!

My solution was to take apart the top portion of the UPS and remove
the Black and Red 18 Gauge wire that goes the the batteries and run
some new 18 Gauge wire out the side of the APC SU2200NET SmartUPS
through a hold I drilled on the case.

I now have my 4 - 12V 17Ah lead acid batteries connected in series
external to the UPS where I can see them and maybe even connect some
sensors to them (Temperatrue, pressure switch, etc...) to avoid this
in the future (Though I am not sure how)

I hope the APC SU2200NET SmartUPS does not kill my next set of 4 - 12V
17Ah lead acid batteries!!!!