Facebook app for iOS was under fire recently for sucking enormous battery life. Facebook engineering manager Ari Grant has confirmed the problem in a post and a bug fixes update is available on the App Store today. If you use Facebook app for iOS, go to the App Store app and update the app immediately.
Facebook has identified and fixed two issues. One was a “CPU spin” issue where the app keep pushing out network queries when there is no response. “This repeated processing causes our app to use more battery than intended” said Grant. The second problem happened when users watched a video and then left Facebook app. The audio session “sometimes stays open as if the app was playing audio silently” explained Grant.
To check battery usage by apps, go to Settings app at Settings > Battery.