Mysterious battery drain My battery has dropped more than the sum of the usage by all of my apps. 

Has anyone ever experienced this before, or know where the rest of my battery is going?



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Android depiction of battery consumption isn't very accurate- see How does Android calculate battery consumption by apps? and I am not aware how much it has improved with the latest version. Having said that, the discrepancy in battery percentage as shown is large and it could be due


a)  Inaccuracy of measurement

b)  Wakelocks (see  tag wakelock for more information)


Inaccurate measurement: To verify this try installing an app like GSam Battery Monitor which gives a more granular breakdown of battery consumption (I am not aware how it measures but in my experience is reliable). If your device is rooted , you could install the helper file of that app to get better results or use BetterBatteryStats, which by far is the best IMO (requires Xposed Framework- see tag xposed-framework for more details )
Wakelocks: can be a major culprit eating into your battery.  To start with, you could install Wakelock Detector- suggesting this as first step since it works on both rooted and unrooted devices (see here and here for more details on installing/ using the app). Once you identify the culprit, following options are available:
System App (rooted devices only): 


You could freeze or uninstall using apps like Titanium backup (there is always a risk of doing so, unless you are sure that it is bloatware and doesn't affect)
Alternatively, limit the wakelocks without breaking functionality using Amplify Battery Extender -Root (requires Xposed Framework)

If your device is not rooted:

a) If it is a system app, there isn't anything you can do

b) If it is a user app, uninstall that app and look for alternate    apps     that don't drain the battery by wakelocks or use Greenify

c) Contact the developer and hope that he fixes the wakelock problem