Now that apple shows battery usage by app, we can finally pinpoint what is causing battery drain and not just base it on a guess. I noticed that my iPad Air 2 on iOS 8.1.2 was draining faster than I would expect for an iPad. It's so subtle that it would take a lot of testing to confirm it in the past but now that we have real data we know. Problem: It turns out that, in fact, 63% of my battery was being used by the mail app background activity for weeks. My settings were: Mail > Data Update > Push ON iCloud (mail sync is off) Push ON 5 mail accounts MANUAL Solution: I turned off push and the problem went away. Questions: Why would push affect mail, when all my mail were pop 3 accounts that had been set to manual and don't even support push? What does Push ON mean exactly, when every email/icloud account has it's own separate option? What overrides what? I never found this clear since the first iPod Touch. Hope this helps anyone who might not even realize they have the problem.