Perhaps the single most frustrating thing for people on a day-to-day basis is the battery in their smartphone doesn't make it through the day. It seems the battery loses its juice earlier and earlier until it's dead before you get home from work. And now, there are rumors all over Facebook that the new iOS update for iPhones is making it even worse.
Some of the posts you might see scream 'Do not update to iOS 11, it's frying the battery!" Well that's just not true
But it is true that people are noticing that their smartphone battery is dying faster than before the update. Have no fear though, it's perfectly natural and it will fix itself.
iOS 11 is a big update from Apple and it changes many things in the settings that have to be re-set. The file system needs to be updated and some files will be reduced in size. All of that work under the hood takes time and your phone will be working harder for the first few hours or even days after installing the update. Once all of that has been completed you should see the battery life returning to what you had pre iOS 11.
So be patient for a bit. When you're not using your phone for an extended period of time, plug it in and keep it charged while the phone updates itself.
If your phone is always running out of juice before the end of the day there are other things you can do to increase your battery life.
Older phones are going to lose battery life sooner than new phones. Like any other battery an iPhone or iPad battery has a life-span. Apple has said that an iPhone battery will lose about 20% of capacity after 400 charges. If you're using an iPhone 6 or 6s that's 2-3 years old you've probably charged it 600-700 times. Some tests revealed that iPhone batteries start losing capacity as soon as 300 charges.