As a rule of thumb, I follow these steps when I’m out & about away from a charger. Works every time!
If you’re in Hurricane Sandy’s strike zone, these six quick tips will mos def prolong your iPhone battery life in case the power goes out….
1. Disable LTE if you have an iPhone 5. If you have an iPhone 4s or earlier, drop down to 2g
Settings > General > Cellular
2. Lower your brightness setting.
Settings > Brightness & Wallpaper
3. Turn off Location Services
Settings > Privacy > Location Services
4. Turn off your Wi-Fi and Bluetooth settings
Settings > Wi-Fi / Settings > Bluetooth
5. Turn off all of your push notifications
Settings > Notifications > Set your apps up accordingly
6. Change your mail setting to Fetch manually
Settings > Mail, Contacts, Calendars > Fetch New Data > Manually