I am using a Samsung Galaxy S4. Something weird happened today morning. I charged my phone yesterday night and went to sleep after 2 hours or so. When I woke up, my phone was at %30 charge and I was pretty confused. Because before going to sleep, I just opened my morning alarm, closed Wi-Fi, and set the phone to airplane mode.

After checking the battery info, I got something like this,

Clearly, my phone discharged linearly while I sleep.

What is the reason behind this? Is this problem related to the phone or Android?

  • How old is the battery? Is the battery disfigured at all, also are you using an AC power supply or usb? And Official leads or not?
    – Sjharrison
    Aug 20, 2014 at 10:29
  • The screen before the one you took the screenshot of should tell you what's responsible for the power use: what does it say?
    – Dan Hulme
    Aug 20, 2014 at 10:39
  • well, everything I use is official samsung products, my battery is new. In my country there were a lot of problems with s4 batteries and I had one too. Discharging immediately after you charged was the problem. I gave it to the official service and they gave me another working original battery. Now I am using a pretty new battery and I think it is not 4 months old yet.
    – atakann
    Aug 20, 2014 at 10:44
  • android os was something like 30% and screen was something like 17% the point is how could this be happened while I was not using my phone.
    – atakann
    Aug 20, 2014 at 10:44
  • 2
    "I always close apps on the background before locking my phone" this alone will drain battery. These apps run in the background and will re-activate themselves. Do not use any task killers on your device, Android itself is FAR better at task management than manually doing it.
    – RossC
    Aug 20, 2014 at 11:59

1 Answer 1


Download Wakelock Detector from the Google Play Store. If it happens again, open Wakelock Detector and it will show you CPU and partial wakelocks (will only show partial wakelocks if you enable advanced mode). If the largest CPU wakelock is "PowerManagerServiceWakelock", this means the largest wake lock is the combination of all the items listed in partial wakelocks.

I would suggest (if it happens again) looking for anything over 7% and doing a web search for the wakelock name, and seeing what you can find.

If it doesn't happen again, problem solved.

I would also recommend you don't kill background processes, instead install Greenify (Play Store) which blocks the processes you select from starting.

Other than this, we can't tell you the reason due to Android's default battery diagnostics not being very good.

It is most probably the software, if you download Nova battery tester and run it, it will tell you your battery capacity, and you can then compare this to what it should be to verify it isn't a hardware fault.

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