Batter health

To learn about 'Maximizing Battery Life and Lifespan', click here --> http://www.apple.com/batteries/maximizing-performance/

Click on this link about 'iPhone Battery and Performance' to read about the battery health feature and what is considered normal performance --> https://support.apple.com/HT208387

- Requires iOS 11.3 and for iPhone 6 and newer iPhones only, not iPad or Watch.

Click on this link to read 'About Optimized Battery Charging on your iPhone' --> https://support.apple.com/HT210512

- With iOS 13 and later, your iPhone learns from your daily charging habits to improve the lifespan of your battery.

- Settings > Battery > Battery Health > Optimized Battery Charging

You cannot increase the battery health level. Batteries decay from the moment they are assembled at the factory as the internal chemicals degrade. Battery health starts off at 100% and from then on inherently decreases. There is no way to stop or reverse that decline in battery capacity. All chemical batteries are inherently consumable devices.