APC UPS replace battery light and apcupsd reporting "replace battery"

We have an APC Smart UPS 1500. The "Replace Battery" light is on, and apcupsd reports:

Emergency! Batteries have failed on UPS xxxx. Change them NOW

However, from this article,

http://sturgeon.apcc.com/kbasewb2.nsf/for+external/f39c4312fcaf7b948525679a005ebb78?OpenDocument

it seems that it's not so clear that the UPS battery needs to be replaced. Stranger, according to the information on the UPS, an 11 minute runtime at 42.9% load running at 27.7V isn't so bad.

Any thoughts about what to try next? We're a non-profit, money is an object. It would be a shame to replace a battery with a year or so left in it.

# apcaccess status
APC      : 001,041,1017
DATE     : Thu Mar 29 13:01:41 EDT 2012
HOSTNAME : oreilly2
VERSION  : 3.14.6 (16 May 2009) debian
UPSNAME  : xxxx
CABLE    : Custom Cable Smart
MODEL    : Smart-UPS 1500
UPSMODE  : Stand Alone
STARTTIME: Thu Mar 29 12:57:30 EDT 2012
STATUS   : ONLINE
LINEV    : 112.3 Volts
LOADPCT  :  42.9 Percent Load Capacity
BCHARGE  : 100.0 Percent
TIMELEFT :  11.0 Minutes
MBATTCHG : 5 Percent
MINTIMEL : 3 Minutes
MAXTIME  : 0 Seconds
OUTPUTV  : 112.3 Volts
SENSE    : High
DWAKE    : -01 Seconds
DSHUTD   : 090 Seconds
LOTRANS  : 106.0 Volts
HITRANS  : 127.0 Volts
RETPCT   : 000.0 Percent
ITEMP    : 23.8 C Internal
ALARMDEL : Always
BATTV    : 27.7 Volts
LINEFREQ : 60.0 Hz
LASTXFER : No transfers since turnon
NUMXFERS : 0
TONBATT  : 0 seconds
CUMONBATT: 0 seconds
XOFFBATT : N/A
SELFTEST : NO
STATFLAG : 0x07000008 Status Flag
SERIALNO : AS0603298896
BATTDATE : 2006-01-14
NOMOUTV  : 120 Volts
NOMBATTV :  24.0 Volts
FIRMWARE : 601.3.D USB FW:1.5
APCMODEL : Smart-UPS 1500
END APC  : Thu Mar 29 13:02:12 EDT 2012

Error when running upstest

You are using a SMART cable type, so I'm entering SMART test mode
mode.type = USB_UPS
Setting up the port ...
Hello, this is the apcupsd Cable Test program.
This part of apctest is for testing Smart UPSes.
Please select the function you want to perform.

1) Query the UPS for all known values
2) Perform a Battery Runtime Calibration
3) Abort Battery Calibration
4) Monitor Battery Calibration progress
5) Program EEPROM
6) Enter TTY mode communicating with UPS
7) Quit

Select function number: 2

First ensure that we have a good link and
that the UPS is functionning normally.
Simulating UPSlinkCheck ...
YWrote: Y Got:
getline failed. Apparently the link is not up.
Giving up.

Perform a rundown test. That will tell you the real runtime of your battery, not the theoretical runtime. It will switch the load over to battery, and run until the remaining runtime or battery charge reaches the minimum allowed value, at which point it will switch back to mains power and recharge the battery.

You shouldn't have any downtime from this, unless the battery fails immediately.

To do so:

• stop the apcupsd service
• run apctest
• select Perform battery calibration