Please go through the following links.
Protect & Prolong the life of your iPhone's Battery: Batteries - Maximising Performance - Apple (IN)
Try some of these options too.
- Avoid Screen Mirroring
- Put on Low Power Mode
- Put Auto-Lock on (1 min):- with the Low power mode it will be 30 Sec
- Disable Push notifications for apps you do not use often
- Keep your iPhone Facedown to prevent notifications to light up the screen
- Enable Auto-Brightness:- Settings > General > Accessibility > Display Accommodations > Auto-Brightness [Enable]
- When possible, manually lower the brightness from Control Center
- If you want to watch continuous Videos/Movies. Stream it on TV or a Monitor
- Don't force close apps; Apps that are not on the frontend screen are paused by the system to save energy. Apps require more energy to re-launch. Apps that are open in the background use large memory is a myth and quitting them is counterproductive
- Location services may please be allowed only while using the app. Avoid the "Always" option wherever available
- Set your iPhone to fetch email & Calendar data from the internet less frequently
- Turning off Background App RefreshÂ
- Charge before it drops below 20-30%
- Periodically Check the Battery Health (Settings > Battery > Battery Health)