Here's how battery health affects your iPhone's performance
After being accused of deliberately slowing iPhones, Apple had promised users more transparency and control over their devices. With iOS 11.3, Apple has introduced Battery Health (Beta) feature that provides information about a device's battery health, allowing users to ascertain if battery's health is affecting their device's performance. So, here's how you can check if your iOS device's battery health is affecting its performance.
Battery Health (Beta), available with iOS 11.3 update
Firstly, make sure your iOS device is running iOS 11.3. To check, go to - Settings > General > Software Update. If you're running an older version of iOS, tap Download and Install to update. Once you've updated your software, go to Settings > Battery > Battery Health (Beta) Under Battery Health (Beta), you see two options - Maximum Capacity and Peak Performance Capability.
Battery Health (Beta) - Maximum Capacity option
Maximum Capacity tells you the current maximum battery capacity relative to when the battery was new - say 98% for a relatively new device as compared to say 79% in an old device. So for a new phone, you won't be able to control throttling as there isn't anything to throttle. However, for users with old devices, Peak Performance Capability option is crucial.
Battery Health (Beta) - Peak Performance Capability
So, if your phone has shut down abruptly, it's perhaps because of power management issues resulting from an old battery. You would see either of the two messages - "Your battery is currently supporting normal peak performance, or This iPhone has experienced an unexpected shutdown because the battery was unable to deliver the necessary peak power." If it is the latter, then your battery needs servicing.
Peak performance comes with a warning
Apple says that disabling the power management function on your devices could lead to "unexpected shutdowns." It also says in some cases that require extreme form of power management, users may experience several issues including longer apps launch times, lower speaker volume and backlight dimming.
