https://www.google.com/#q=android+which+app+is+draining+battery is the usual find.

That is I find apps to be the usual cause.

-> There are now thousands of web pages about optimizing battery time (some call it life) in Android. Let me share mine.

Last month I picked up a new Blu HD 6.0 Android phone. Among it's tricks is to power off and back up on a schedule. Brilliant. I don't need it on from say 12 midnight to 6AM. I gained an instant 33% of battery time. Now it goes days on a charge.

I also turn off GPS and Bluetooth as usual and kick it into airplane mode a lot.
Bob