How to diagnose battery drain on Android device using logcat?
Are you sure, it's not any app that is draining your battery? You can find this out by booting you phone into Safe mode. Read How to boot your phone into safe mode for instructions. If your battery doesn't drain in Safe mode, try uninstalling the apps that you installed after you started seeing this weird behavior. If you are not able to figure out which app it is, try factory resetting it. Also, if the battery is draining so quickly it might very well be a faulty battery.