Optimized Battery Charging is a feature available on iPhones running iOS 13 or later that is designed to reduce the wear on the battery and improve its lifespan by reducing the time the device spends fully charged. When the feature is enabled, the iPhone will delay charging past 80% in certain situations, and it uses on-device machine learning to learn the users daily charging routine so that it activates only when the iPhone predicts it will be connected to a charger for an extended period of time. The algorithm aims to ensure that the iPhone is still fully charged when unplugged. Optimized Battery Charging is on by default when the iPhone is set up or after updating to iOS 13 or later, but it can be turned off in the Battery Health & Charging section of the Settings app.

When Optimized Battery Charging is active, a notification on the lock screen shows when the iPhone will be fully charged, and if the user needs to have the iPhone fully charged sooner, they can touch and hold the notification and then tap Charge Now. The feature is designed to engage only in locations where the user spends the most time, such as their home and place of work, and it doesnt engage when usage habits are more variable, such as when traveling.

Optimized Battery Charging is also available on Macs running macOS Big Sur or later, and it is designed to improve the lifespan of the battery and reduce the time the Mac spends fully charged. The feature limits the charging to 80%, but it can be turned off if desired.

In summary, Optimized Battery Charging is a feature that helps to reduce the wear on the battery and improve its lifespan by reducing the time the device spends fully charged. It is available on iPhones running iOS 13 or later and Macs running macOS Big Sur or later, and it is designed to engage only in certain situations to ensure that the device is still fully charged when unplugged.