6 tips for preserving your iPhone’s battery life…
1. Battery & App Management
2. Low Power Mode
Low Power Mode lets you extend the life of your battery. Stops many background activities such as mail fetch, app refresh, and auto downloads. You may have noticed once your battery hits 20% charge remaining, your iPhone asks you if you wish to place your phone in Power Save mode! We suggest you do, in fact if you’re a heavy phone user, it is a good idea to enable Power Save mode earlier to conserve your power.
You can turn on Low Power mode under Settings → Battery. However, it’s really useful to have quick access to Low Power Mode by adding it to iOS 11’s redesigned Control Center. Navigate to Settings → Control Center → Customize Controls, then tap the 
sign next to Low Power Mode.
3. Background App Refresh
Low Power Mode turns off background app refresh across the board, but you can customize which apps use this feature for a more convenient experience as well as improved battery life. Head to Settings → General → Background App Refresh.
You can also opt to only use background app refresh when you’re connected to Wi-Fi, however, most users will find leaving Wi-Fi and data on while customizing which apps are used for background app refresh to be the best fit.
4. Location Services
Taking a look at your location services settings is another way to be more efficient with battery life (and cellular data usage). Head to Settings → Privacy → Location Services to update the privileges for your apps.
Watch out for any apps that ask to Always use your location and switch to While Usingor Never.
6. Push and Fetch
Taking a look at your push and fetch settings is also worthwhile. Navigate to Settings→ Accounts & Passwords → Fetch New Data. One possible approach is to leave your primary account(s) as push to receive new mail asap, and turn secondary/non-crticial accounts to fetch every 30 minutes or hour.
After fine-tuning these settings, you should find yourself with improved battery life with iOS 11. While not always ideal for everyday use, power banks can also prove useful for the times you’ve run out of juice unexpectedly. With so many options, keeping one with you can be a lifesaver.