A battery’s lifespan is related to its chemical age, which is more than just the length of time since the battery was assembled. A battery's chemical age results from a complex combination of several factors, including temperature history and charging pattern. All rechargeable batteries are consumable components that become less effective as they chemically age. As lithium-ion batteries chemically age, the amount of charge they can hold diminishes, resulting in reduced battery life and reduced peak performance. Learn more about iPhone battery and performance and how to maximize battery performance and lifespan.
iOS 13 uses Optimized Battery Charging to slow the rate of battery aging by reducing the time that your iPhone spends fully charged. Your iPhone uses on-device machine learning to understand your daily charging routine so that it can wait until you need to use your iPhone to finish charging past 80 percent.* Charging in this way reduces the wear on your battery and improves its lifespan. Optimized Battery Charging is active only when your iPhone predicts that it will be connected to a charger for a long period of time.
Optimized Battery charging is on by default when you set up your iPhone or after updating to iOS 13. If you notice that your iPhone is often only partially charged—for example, if you don’t charge your iPhone overnight—you can go to Settings > Battery > Battery Health and turn off Optimized Battery Charging.
When optimized battery charging is active, a notification on the Lock screen says when your iPhone will be fully charged. If you need to have your iPhone fully charged sooner, touch and hold the notification and then tap Charge Now.
* Information regarding your charging routine is stored only on your iPhone. The information isn't included in backups and isn't shared with Apple.