Thanks for reaching out in Apple Support Communities. I understand that since updating to iOS 11.2.5 you're having trouble with your battery draining faster than normal. I know how important it is for your device to stay charged properly, I'd like to help. First I'd recommend reviewing the information here regarding iPhone Battery and Performance
Next, you can use these steps to see how your battery is being consumed as well as Settings you can change to get the most from your battery:
About the battery usage on your iPhone, iPad, and iPod touchCheck battery usage
Go to Settings > Battery.
To see how long each app has been open and running in the background, tap . Under each app, you might see these usage types:
- Background Activity means that your battery is used while apps run in the background.
- Audio means that apps play audio while running in the background.
- No Cell Coverage and Low Signal means that your device is searching for a signal or being used with a low signal.
- Backup & Restore indicates that your device has been backing up to iCloud or restoring from an iCloud backup.
- Location and Background Location means that your battery was used when tracking your device.
Adjust settings to improve battery life
While viewing your battery usage, you might get a suggestion like Enable Auto-Brightness or Adjust Display Brightness. This is because iOS determined that changing these settings could improve your battery life. You can also see the usage times since the last full charge.
Learn more about maximizing the battery performance and lifespan of your iOS device.
Best Regards.