Ultimate Battery Info is a FREE AD-FREE iPhone application, shows you a big graphical battery and text of exact battery level left & current battery status.
It will show the following battery status: "Fully Charged", "Charging", and "Discharging". It will disable sleep so that you can watch your battery info anytime easily.
If you would like to have more information about your device, please check out our application of "Ultimate System Info". It allows you to , and many more.
Note: This application requires iPhone OS 3.0 or later.