Hello, I am unable to find this weird behavior discussed on line for iOS 11 yet. I have found out accidentally, that one of my applications was using ~ 15% battery (in 24 hours) on background refresh. BUT, that application had background refresh disabled. Could not stop it from doing it, so I deleted the application. Except, next day there was another application using ~20% of battery for background refresh - again, in Settings this application had background refresh disabled. Eventually, I deleted it. And yes, today yet another application shows ~5% of my battery used by doing Background refresh, even though it has Background refresh disabled. I tried various common sense fixes, but nothing seems to help. There must be some bug which lets one (first or last on some list) application do background refresh even when it is disabled. If you have bad battery life, check if you have such application and how much battery life it uses. For me it is easy to identify - I have only 8 applications which are allowed to do background refresh, so I can find culprits easily.