battery calibration is needed each time you flash a new custom Android ROM. The aim is to fully charge your battery, delete the batterystats.bin file and then unplug the phone letting it FULLY deplete the battery (until phone powers down) before charging the battery to 100% without interruption. The Android OS will create a new batterystats.bin automatically which will then know the correct maximum and minimum charges of your phone!
The batterystats.bin can be deleted directly from /system/data/batterystats.bin. But there is an excellent lightweight app “Battery Calibration” to do this for you.
- Download Battery Calibration from the Android Market.
- power up your phone, connect to charger or USB to a computer (for charging)
- open Battery Calibration and wait until the voltage meter hits 4200 mv,
- hit the calibrate button (deletes batterystats.bin)
- unplug the phone and allow it to fully drain then charge the phone back to 100%.