How to improve your iPhone or iPad battery life with iOS 11

Location services use GPS for location-aware apps and services. While it’s useful knowing where you are on a map, what you don’t see is what is going on behind the scenes. Ads are being displayed based on your location, and traffic data is updated — meanwhile, your iPhone or iPad is always pinging out to see where you are. All of these things are unnecessary and churn up your battery life.
Go to Settings > Privacy > Location Services. When On, scroll down to System Services, then uncheck all of these items. When you’re not using Location Services, such as GPS, simply turn it Off.