Hot answers tagged battery
It's understandable that your battery life will decrease when you run 4.4 on an older device like the S2. But that is strange. Try identifying the process like the other users suggested. I would also suggest Greenify, an app that can put processes and apps into automatic hibernation, decreasing their CPU toll.
If you are rooted, I would recommend downloading Better Battery Stats (or Wakelock Detector) from the Google Play Store, and finding the name of the 'mad' processes. If you aren't rooted, I recommend you root as other apps can't access battery stats as of Android OS version 4.4.
It is normal. It could have been because your daughter was playing a game on the phone, or just taking up a lot of processing power. Also, having one's hands on the back of the phone also does not help. I've had this issue with multiple devices when playing games specifically.
Should be an hardware issue. In my case was the oxidation of the motherboard cause by the sweat cuase i kept the phone on my arms while I was running.
This website has a good page on the information: http://nexus7.wonderhowto.com/how-to/unlock-android-ls-hidden-battery-percentage-icon-status-bar-0155876/ But if you want a quick and dirty way to enable this, you can just use: adb shell content insert --uri content://settings/system --bind name:s:status_bar_show_battery_percent --bind value:i:1 followed ...
To expand on @RossC's comment, doing this yourself is quite easy if you are confident and comfortable with device disassembly, and have the correct tools. There are tutorials on how to safely and correctly replace this: iFixIt: https://www.ifixit.com/Guide/Motorola+Moto+X+Battery+Replacement/16974 ETradeSupply video: ...
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