Battery Calibration is helpful app, which you should use when you think that your battery is performing bad.
Battery Calibration also shows you some battery parameters like temperature, charge level, general condition, etc.
How should you use Battery Calibration? Here is some manual:
1) Charge your phone until the battery is 100% full.
2) Click 'Calibrate!' button.
3) Let the battery completely discharge.
4) Charge the battery once more to 100%.
Note that this free application is ad supported and contains ads.