So first of all, check out this tip I wrote on a similar feature in iOS 8 a while back. With that, you can see the percentage of battery each app has used, and it’s fairly simple to then nix any energy hogs if you need to. In iOS 9’s beta, though, this feature is in a different location—instead of being tucked under Settings> General> Usage, “Battery” has its own section right within the Settings app.
If you tap on that, you’ll see a similar view to what we had with iOS 8, but there’s a new icon all right up in your face. That’s where the magic is.
If you touch that, you’ll get far more detail about what each app is doing (and how much time it spent doing stuff in the background):
Oh, so cool! And darned useful, especially for those of us who have to charge our devices more than once a day. Yes, I know I have a problem, all right?