Many people ask us where we got the battery images on our Apple iPhone that show the percentage (%) of charge. The simple truth is that we made them ourselves, using our favorite graphics program. As it happens, "custom iPhone battery images" is one of the key search phrases that leads people to the iPhoneWriter.com website.
So, in the spirit of giving people what they want, here is the link, to download our variation of the stock Apple iPhone battery icon. The archive includes all 17 images and the image backgrounds are transparent, so you can leave them as is for a stock look and feel, or set them to whatever color you prefer based on your current skinning desires.
NOTE: In case you're wondering or unsure, the Apple iPhone's battery images are stored inside the "/System/Library/CoreServices/SpringBoard.app/" directory structure.