Tutorial: How to calibrate Android device battery with root access
What does it mean to calibrate a smartphone?
The Android operating system has a feature called Battery Stats, which keeps track of battery capacity, when it is full or empty. The problem is that it sometimes it become corrupted and starts displaying data that isn’t real, which, for example, causes the phone to turn off before reaching 0 percent. Calibrating your Android battery simply means getting the Android OS to correct this information so it is reflective of your actual battery levels once again.
It's important to understand that you can't actually calibrate the battery: it is, after all, just a cell that stores and discharges. However, lithium-ion batteries do include a printed circuit board (PCB) that serves as a protection switch to stop them from exploding or deep discharging.
Even though I'm not convinced that clearing the batterystats.bin file has any meaningful effect on how the Android system reports remaining battery charge, there are those who swear by this method. So in the interests of fairness we've included the process for you here (it is true that different manufacturers use the batterystats.bin file for different things). It's basically the same process as above but with the added step of a root-enabled app.
Method 2
1. Discharge your phone fully until it turns itself off.
2. Turn it on and let it discharge and turn off again.
3. Plug your phone into a charger and, without turning it on, let it charge until the on-screen or LED indicator says 100 percent.
4. Unplug your charger.
5. Turn your phone on. The battery indicator will likely not say 100 percent, so plug it in (leave your phone on) and continue charging until it says 100 percent on the screen as well.
6. Unplug your phone and restart it. If it doesn't say 100 percent, plug the charger back in until it says 100 percent on screen.
7. You want to repeat this cycle until it says 100 percent (or as close as you think it's going to get) when you start it up without being plugged in .
8. Now, install the Battery Calibration app and, before launching it, make sure your battery is at 100 percent again, then restart.
