John Rumm wrote:

APC have a reputation for being hard on batteries
http://wiki.diyfaq.org.uk/index.php/File:Wonkybatt1.jpg
http://wiki.diyfaq.org.uk/index.php/...wonkybatts.jpg

Here's one where the UPS was in an unventilated broom cupboard with a
half-height rack of IT kit

http://adslpipe.co.uk/photos/APC_UPS_battery.jpg