The stock battery icon while serving its purpose can be quite a bit boring. The main complaint that most people have with the stock battery icon is that it is white and just kind of plain. If your current battery icon is just not your style you can change it thanks to the 3Minit Battery Mod by developer "gharrington". This mod does require root. The app allows you to choose from over a thousand unique hand made battery icons which will download upon selection (meaning you won't have to worry about this app eating up your memory). To use this mod you will first download the app, decompile the systemui.apk using apk tool v1.5.2, change a few lines of code, download and replace the mod smali files, and recompile settings proper permissions. Once you have completed these steps you will be able to apply any of the battery mods from the app which will appear in your status bar. For full instructions and downloads head to the link below.
via XDA