How to calibrate the battery on your Android device

By | February 4, 2015

This is just a simple guide on how to calibrate your battery on an Android phone or tablet. Most guides out there advise you to delete the batterystats.bin file in /data/system however this isn’t correct. A Google Engineer by the name of Dianne Hackborn posted a debunking on Google+ about wiping that file.

“The battery indicator in the status/notification bar is a reflection of the batterystats.bin file in the data/system/ directory.”

No, it does not.

This file is used to maintain, across reboots, low-level data about the kinds of operations the device and your apps are doing between battery changes. That is, it is solely used to compute the blame for battery usage shown in the “Battery Use” UI in settings.

This file is used to maintain, across reboots, low-level data about the kinds of operations the device and your apps are doing between battery changes. That is, it is solely used to compute the blame for battery usage shown in the “Battery Use” UI in settings.

Now some may say that running the device to zero has a negative effect on the battery (and feel free to comment about it). There is more in-depth information over at Battery University. However there was once a quote on the Apple website that stated: For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally. Be sure to go through at least one charge cycle per month (charging the battery to 100% and then completely running it down).

Sometimes across reboots or after flashing ROM’s you may notice that the battery percentage changes (I’ve noticed mine goes from 5%, to 6% or 8% after I reboot). So that is time to recalibrate.

To calibrate your devices battery I have created step-by-step instructions you can follow.

  • Run your devices battery down to zero (until the device powers itself down).
  • Turn the device on and make sure it turns off at the boot animation. If it doesn’t, run it down to zero again.
  • Leave the device off and charge it to 100%.
  • Turn your device on while still plugged in.
  • If the battery is at 100%, unplug the device. If not, continue to charge.
  • Once unplugged, use device as per normal and repeat once per month.

Don’t judge your battery life from a partial drain (from 100% to 85%). The battery drain isn’t a constant. You could lose 20% in the first hour, then only 5% in the next. You should base your battery drain from 100% to 0%.

If you do flash daily / weekly ROM’s on your device, make sure it is plugged in and charged to 100% when flashing the updated rom to maintain the correct readings.

P.S. This is my 300th post!