Go to "Settings," "General," "Background App Refresh," and hit "Off." Then, go to "Accessibility," "Motion," and hit "Reduce Motion." Then, go to "Privacy," "Location Services," and go down to "System Services." Turn off "Location-Based Alerts," "Location-Based Ads," and "Location-Based Suggestions." Scroll down and turn off "iPhone Analytics," "Popular Near Me," and "Routing and Traffic." This will significantly help your batter life last longer.