With the sole intention of helping people who are having battery drain issues I thought I would write the following thread to try to help people diagnose a problem/s. From my own experience I know firsthand how frustrating battery drain diagnoses can be, but there are methods you can use to help with this.
There does seem to be many various problems and causes with regards to battery draining, and a lot of the threads on this forum at present seem to be getting quite heated, which at the end of the day doesn't help anybody.
A lot of these problems can be overcome by using some investigating measures to find the culprit and/or rule out any hardware issues. There are a selection of apps which have been written to aid us in finding out what is causing a drain, whether that is in standby mode or whilst in use.
Rather than just posting on the forum saying my battery is rubbish, try the following steps / apps beforehand and we will be in a much better position to help you diagnose a problem. The aim on this forum is to help each other but it is almost impossible to guess a battery drain problem without seeing the whole picture. Download the following apps.
1) 'Better Battery Stats' app (either in the play store, or free if you are a member on xda-developers site here http://forum.xda-developers.com/show....php?t=1179809
2) 'GSam battery monitor' app. (available for free in the play store)
With these apps you can check up if certain apps/features are causing your battery to drain, which narrows down the possibilities.
I previously had a very bad drain on my battery, which I initially, wrongly thought was hardware related. I overcame my drain issue using these apps and some patience by testing day on day, my battery now lasts exceptionally well both whilst in use and in standby mode.
Not always the case - but It is more often than not a rogue app/apps that cause a battery drain rather than a problematic/faulty phone. I spent weeks/months thinking I had a faulty phone/battery, then discovered these battery apps to find the problem... as I said above my battery lasts very well now. It just takes some patience to find the culprit.
To help you, we need the full picture of what is going on behind the scenes.
Better battery stats, and GSam battery monitor have been written to aid us with this. The option on these apps, labeled 'since unplugged' is a good reference to use. With GSam battery monitor, if your problem is a standby mode drain, pay particular attention to the apps sections 'View time held awake' and 'View num times waking device'. If your phone is draining excessively whilst the screen is on - we need to look at all sections then narrow it down.
Try these and report back with the findings/screenshots (Ideally screenshots) either here or in your individual thread and we may be more likely to be able to help you.
As well as the above information we will also need to know your screen on time to correlate with the battery apps results. To do this go to Settings >> Battery >> click on screen and it will tell you the screen on time.
I hope these methods can help people, from my personal experience they helped no-end. If anybody else has other methods which they have successfully used to diagnose a problem please feel free to post here in the hope of making life easier for users to find methods/answers - all in one place.