Here are few other things that you can do to improve your battery life.
1. OS 9’s Low Power Mode
iOS 9 has a new feature – Low Power Mode. iOS 9 is said to provide an extra hour of battery life. To get the most out of your battery, start using the Low Power Mode by navigating to Settings > Battery > Low Power Mode and turning it on.
2. If you don’t use the iCloud Keychain, disable it. To turn iCloud Keychain off, navigate to Settings > iCloud > Keychain and toggle it off.
3. Location services use a substantial amount of battery. If you want to turn Location Services off, go to Settings > Privacy > Location Services and toggle it off.
4. If you get a lot of alerts for unwanted events and posts, you are advised to turn your push notifications off. To do this, go to Settings > Notifications and turn off the app that you don’t want to be notified about. This will save your battery life altogether.
5. If you don’t use your phone to track steps and activity, it's s good idea to to turn off the Motion & Fitness feature to save battery life. Go to Settings > Privacy > Motion and Fitness and toggle it off.
6. Spotlight searches all apps and services including Web, music and more. It is constantly running, and indexing the contents of your phone, thus using a lot of battery life. If you rarely use it, consider turning it off by going to Settings > General > Spotlight Search.
7. The App Store automatically installs updates for pre-installed apps. If yu want to maximize your battery life you can turn it off and install updates when it suits you, like when you are plugged in to power . To turn off automatic updates go to Settings > iTunes and App Store > Turn off ‘Updates’ from Automatic Downloads section.
8. When you are not connected to a Wi-fi network, your phone is continuously searching for available networks. This can be a HUGE drain on your battery, so when you're away from your home or office and not connected to wifi, turn it off. to do so, touch Settings > Wi-Fi, and slide the Wi-Fi button from On to Off.
9. The same is true of Bluetooth. If yo are not actively using it, turn it off by going to Settings > Bluetooth and slide the Wi-Fi button from On to Off.
Taking the time to make these changes should result in noticeable improvement in your battery life.