This is a geeklet highly inspired by midnighttokerkate's Volume indicator.
To set it up, start by downloading the Circle Volume Indicator Geeklet: http://www.macosxtips.co.uk/geeklets/system/circle-volume-indicator/
Then download the BattIndicator script on this page.
Then, just rename the folder "Circle_Volumeindicator" to "Circle_BattIndicator" and replace the VolumeIndicator.scpt file in the folder with the BattIndicator.scpt file. From there, you can follow all of the instructions included with the Circle Volume Indicator, but replacing "VolumeIndicator" with "BattIndicator" every time you see it.
Enjoy!
