[CQ-Contest] Another quick UPS question

[Mark Beckwith]

All this UPS talk is making my head spin.  Sorry.  Simple question:  I have
stupid blackouts which last about a second about twice a month because I
have a stupid power company.  Complaining did not work.  I got a UPS - an
APC ES350.  It worked for a year.  But now, when I get home and the alarm
clock is flashing, the computer has rebooted and the answering machine is
back to Mr. JA-san saying "please-leave; A MESSage."  Obviously the UPS has
become an IPS.

Do I have to replace the battery in the UPS?  Is this a common thing?  How
do I know?  Internet source for these batteries?

Sorry this is off-topic, but theoretically it could happen during a contest
and I need to be prepared  :)

Mark, N5OT