Removing this one app could increase your iPhone's battery life by 15%
battery drain on the Apple iPhone. Late in 2015, Facebook took ownership, admitted the problem and offered a remedial update. Unfortunately, said update hasn't completely resolved the issue, and if you are worried about Facebook's effect on your iPhone's battery, you may wish to consider deleting the app completely for now.Facebook's impact on mobile battery has been the subject of debate for a number of years now. Back in 2013, one developer discovered that its apps were to blame for
By deleting the app and using the Web app within Safari, you can still enjoy a near full-on experience. Sure, one or two features are not available, such as the handy 'share to' function. But along with the battery life saved, you also stand to recoup a fair lump of storage space as well. The app itself is just over 100 megabytes installed, but that cache can build up mightily fast, and after prolonged usage, the Facebook app will have no problem commanding several hundred MB of real estate.
If Facebook's presence caused a 5 percent increase in battery, then perhaps its impact could be ignored. But until Facebook improves things, using Apple's Safari browser (or ditching Facebook entirely) will keep your device running for quite a bit longer.
source: The Guardian