The default power indicator in Ubuntu 11.10 works out of the box, but in previous releases support was patchy at best.
For Lucid, Maverick and Natty users installing the Battery Status Applet is a no-brainer. It offers up stats on your current battery charge, grants quick access to performance scaling and Power Management settings, all within easy reach.
Battery Status is available for Ubuntu 9.10 through 11.04 via the following PPA:
* sudo add-apt-repository ppa:iaz/battery-status && sudo apt-get update
* sudo apt-get install battery-status
The applet will, initially, run as a standard gnome applet. To intitate ‘indicator applet’ mode you will need to run the following command in a Terminal : -
* /usr/lib/battery-status/battery-status --indicator