This will re-calibrate your battery. Your problems happen when the phone operating system thinks the battery is 100% charged when physically phone battery is only 60%. Or vise versa when physical phone batter is 100% and operating system thinks its 60% (or what ever value). Hope this fixes all your battery problems.

1) drain all of your battery untill phone shuts down

2) turn on and drain battery until phone shuts down ( repeat until you are unable to turn the phone on- this step is very important because we need to drain the battery competely)

3) take the battery out and wait 5 seconds or so and put it back in

4) Charge the battery while the phone is off

5) when the charge is 100%, take the charger off then charge again to get 100% again

6) turn on your phone and enjoy your new battery