I recently purchased an extended battery for my ailing Galaxy S4. It's supposedly rated at 4000 mAh over the previous 2600 mAh OEM battery.

First time I threw it in, I turned on the phone, chucked in the battery, and sat it on the charger for an hour or so.

It actually lasted a pretty long time. About 2 days and 5/6 hrs. SoT (not fantastic for 4000 mAh, but it's new so what the heck).

So, listening to the advice of others, I threw it on the charger until completely topped off while the phone was shut down. Again, I discharged it from 100%. However, this time, the battery drained much faster than usual. There weren't any particular apps draining the battery, it just drained faster.

Seeing as this was strange, I drained it to 0%, and charged it back up. Still, the same terrible battery drain. It may be I have to cycle it a couple more times.

Advice? How should I correctly calibrate an extended battery?

  • Good that the problem is resolved. You can post your solution and accept it to show that it was ROM related and not battery files as I suspected ( deleting my answer not being pertinent in your case). On second thoughts, your mention within fine first time should have triggered that alternative. I was blind to it
    – beeshyams
    Commented Feb 3, 2017 at 14:21

1 Answer 1

  • Firstly, battery calibration is a myth, normal or extended battery. See Bought a new battery, do I need to calibrate it?

  • Next, with extended batteries, there is always a possibility that the correct capacity of the battery is not being read by the ROM and displayed ( since there are two different sources for reading the battery capacity and it may be reading from the hardcoded (ROM) rather than battery capacity files. See for more details here Where are the battery capacity files located?)

What you can do

  • Measure the actual capacity of your battery as explained here How to determine maximum capacity of a battery in mAh? - received fake battery using the app mentioned.

  • Adjust the capacity of the battery manually in the app (from Battery Manager → Tap the 4 small square icon → Adjust Capacity or use Configuration Wizard) and create a shortcut on your home screen for the Battery Mgr widget and use that to measure

You can optionally avoid the first step above if you trust the battery provider capacity and adjust on the app

  • Thanks for your answer! As a rooted user, I deleted the batterystats.bin file, but apparently that's wiped at full battery capacity as well.
    – negusp
    Commented Jan 30, 2017 at 20:26
  • Sorry, accidentally pressed enter. My GS4 has it's battery files in /sys/devices/platform/sec-battery, but average capacity and min/low are unreadable by root explorer. I will discharge and recharge this battery a few more times and see how it goes.
    – negusp
    Commented Jan 30, 2017 at 20:27
  • 1. Battery stats. Bin here re created when fully charged or on booting -that's a part of the reason, calibration is a myth as mentioned in my linked answer 2. Do not know about your device battery files so no comment 3. I think you may not have understood my answer, so let me clarify //
    – beeshyams
    Commented Feb 1, 2017 at 4:40
  • Your device ROM may be reading the battery capacity files from the location you mentioned, since the ROM knows the expected Max capacity of battery as stored there. It can't recognise a new battery with larger capacity. Hence, usage ratings are wrong.Using the app mentioned, you can force the app to read the new capacity as explained in answer. This will correctly determine usage stats. Only disadvantage of this is that it won't change the notification status of battery but you will have to depend on the app readings instead. This is my best guess. Putting it through more discharge//
    – beeshyams
    Commented Feb 1, 2017 at 4:45
  • Cycles is not going to help. Use the app to force read new capacity and then see if the usage makes sense
    – beeshyams
    Commented Feb 1, 2017 at 4:47

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