Manually Turn On Low Power Mode
One of the best new iOS 9 features for your iPhone is Low Power Mode. Low Power Mode is designed to kick in when you reach 20% battery remaining, and give you a little more time before you have to race to a charger. Most people don’t know that you can also do this manually and don’t have to wait until your iPhone’s battery hits 20%. Flip on Power Reserve Mode manually by going to Settings >> General >> Battery >> Low Power Mode.