How do I recalibrate the battery of my phone?

Question

After a year using my phone, I noticed the battery drains too fast, but after shutting down I manage to make it work again for a couple of minutes before it shuts down automatically.

I read that to recalibrate the battery, you should fully charge it and by various means delete the batterystats.bin file. (examples with clockworkmod or using an app)

The thing is...

"When you follow the steps to recalibrate your battery and delete the batterystats.bin file from your phone, you are getting rid of more than what you think… Stored inside that batterystats.bin file, your phone keeps detailed logs of the capacity of your battery and uses it on how it can be utilized more efficiently." Read Full

or oppositely, quoting Dianne Hackborn

"It (refering batterystats.bin) has no impact on your battery life."

I know it's not possible to make it as good as new, but at least reset it in a way it would read that last bit of energy accurately?

Answer 1

Android shuts down your OS before it actually becomes completely flat, in order to ensure it has enough power to do so safely and completely (which is why you can power it back up again, but then it shuts itself off again). Over time, your battery does need to be recalibrated as the system stats on battery usage get wonky and the battery itself won't store as much of a charge as it could.

For most phones, the proper procedure is:

1. Let the phone run until it shuts itself off.
2. Without turning the phone on, plug it in and let it fully charge up.
3. Unplug, turn the phone on and let it run flat again.
4. Battery and battery stats are now recalibrated.

Deleting batterystats.bin isn't generally necessary.

You should find your battery lasting much longer now (I know this works well on my Samsung SK4G - I go from not being able to last the day to being able to last a full day and night)

If memory serves, one is supposed to recalibrate one's battery like this every 30-90 days.

Answer 2

Recalibrating your battery won't actually make it last longer. What it might do is ensure that the battery level display is more accurate, so that when it says it's at zero, it's actually at zero.

Personally, I used an app like Battery Calibration (requires root) and it seems to help. To be fair though, I haven't actually tested the actual levels myself, so it's a qualitative judgement.

If you're having battery life issues it's more likely that you apps running (background or otherwise) that are draining your battery. Either go to Settings > Battery and check out which apps are draining your battery the most - typically it will be your screen, then cell/wifi radios.

Sadly, the only true "reset" is to go out and buy yourself a new battery. Sorry!