The battery indicator in Gnome seems to work fine.
Sometimes it gets
confused when I put the laptop to sleep on A/C on and wake it up on battery
(shows too little battery left).
I've noticed that recently. If you query the battery directly through
/proc, you'll probably see that Linux is reading the battery status
properly, but for some reason Gnome shows it incorrectly. That just
popped up in the past few months.
Monty