You can check that your battery is detected by HAL using the command
hal-device-manager. If your battery is not detected
by HAL or the wrong information is being reported, you can attempt to
disable the HAL backend by setting a GConf key.
Select Configuration Editor from the
Applications menu, under
System Tools. Search for the key value
OAFIID:GNOME_BattstatApplet which should be located in
the path /apps/panel/applets.
Assuming the path is /apps/panel/applets/applet_1.
In /apps/panel/applets/applet_1/prefs add a
New Key... called no_hal
and set it to the boolean value of true. This will disable the usage of
HAL (see  to learn how
to check this).
