http://uk.businessinsider.com/unins...oid-will-save-up-to-20-of-battery-life-2016-2
Facebook does not have the greatest track record with its Android app. Users have long complained about performance issues and it sucking up battery and last year Facebook’s chief product officer, Chris Cox, took the unusual step of making his staff ditch their iPhones and move to Android until they sorted out the issues. But the problems have remained, and recently they led the Android blogger Russell Holly to dump the app, starting a chain reaction which revealed something rather interesting about the app’s performance.
It's amazing to see that facebook is such a resource-hungry app on Android smartphones...