Originally Posted by natashaleslie
Both the phone and that app report that the screen is causing all the battery drain
Go to the Battery usage
screen, and you'll see a %age listed against "Screen" - that's the %age of screen-on time vs time on battery, as displayed at the top of the graph. Now tap "Screen" and you'll go to another display that shows the actual screen-on time; that should tally with the %age shown previously.