How does calibration works?
Why calibrate my battery?
The process of calibration helps maximize battery life by 'teaching' Android the maximum % and voltage range supported by the battery.
This will ensure the longest running time on battery and enhance the life of the battery.
How to to calibrate my battery?
The calibration process does not require any application! It's a matter of running full charge and discharge cycles. An app can definitely help though!
A full charge cycle starts at near 0% and ends at 100% when the battery is not charging anymore (usually one hour to two hours after reaching 100%).
A full discharge cycle starts at 100% (best after a full charge cycle) and ends at 0% or more realistically when the phone shutdown by itself and it becomes impossible to restart it without plugging it in.
What can I gain from battery calibration?
Simply said, without calibration a device might shutdown at 3% or charge upto 99%. After running calibration a few times it will shutdown at 1 or 0% and charge up-to 100%. Tested on an Iconia A500 and a HTC Sensation!
How can Battery Monitor Widget help calibrate my battery?
The app can help set an alarm for an actual end of charge, and also measure the % and voltage ranges.
It will then measure the aging total battery capacity from a starting value (usually the device's specs).
How to use the Calibration screen?
You first need to run some full charge and discharge cycles. At least from 100% to 3%. It is best to run the cycles until the % and voltage ranges are maximized. This screen can be used to check range evolution over time.
Once the ranges are maximized, this can be used as initial real-life specifications (which may slightly differ from manufacturer's specs), except the actual battery capacity which usually follows specifications.
Over time, the calibration screen will provide information on battery aging and it's new total capacity.
Let's consider an example with a HTC Sensation device. A battery having a voltage from 3200 to 4200 with a capacity of 1520mAh. That's the manufacturer's specs but real-life shows it's different (for every phone).
On that phone I initially got a voltage ranging from 3353 upto 4206, capacity from 3% upto 100%.
After 3 full charge/discharge cycles ranges went to 3170-4212 and 1% upto 100%!
If in the future voltage ranges from only 3230 upto 4196 (as it happened with an old HD2 battery), then the actual capacity will be reduced accordingly.