The iPhone 15 series is now official and with the new USB-C comes a new software feature. According to a source code found in iOS 17 beta released to developers, Apple may let you limit the maximum battery charge on your new iPhones. It seems like the feature will be available only on the iPhone 15 series.
The feature itself is pretty straightforward – you limit the maximum charge to a certain percentage, which limits the time your battery spends at full charge, which theoretically should preserve battery health over time. That obviously comes at the expense of not using your full battery and only brings benefits if you like leaving your phone on the charge for a long time such as overnight charging.
Normally, iOS will display a message on the lock screen telling you your iPhone will charge to its full capacity and when this feature is enabled, it will warn you it will only go to the maximum charge level set.
Notably, this is different from the Optimized Battery Charging feature as seen on some Android phones, which would keep the phone at 80% and fill the rest just before you unplug the phone as it learns from your charging habits.