iPhone battery life even shorter than normal? Here's an easy solution.
You're not doing anything out of the ordinary, you're using your iPhone as much or as little as you normally do but your battery is just draining, and it's draining quickly.
Time to switch your phone's Background App Refresh off.
Go to Settings: General: Background App Refresh. (image below)
Go down the list and turn the ones you rarely use off. You definitely want Facebook off since, apparently, it's the biggest culprit since a recent app update.
There! That ought to help!