As part of today’s iOS 11.3 update, Apple has finally unveiled their promised Battery Health tool. Using the Battery Health tool, owners of iPhone 6 and later can check whether their battery is performing optimally, if the speed of the phone has been decreased due to the battery, and if it needs to be replaced.
To access the Battery Health tool, you need to go into Settings, then tap Battery, and finally tap on Battery Health (Beta) as shown below.
The Battery Health (Beta) screen will then show you the “Maximum Capacity” of your battery, with the higher the number the better.
According to the Battery Health support article:
Maximum battery capacity measures the device battery capacity relative to when it was new. Batteries will start at 100% when first activated and will have lower capacity as the battery chemically ages which may result in fewer hours of usage between charges.
A normal battery is designed to retain up to 80% of its original capacity at 500 complete charge cycles when operating under normal conditions.
The screen will also contain a section called “Peak Performance Capability” that will tell the user if the battery is running normally or if it is being slowed down to prevent bugs from occurring. If the battery is operating normally, it will display “Your battery is currently supporting normal peak performance”.
On the other hand if a problem has been encountered due to the battery, iOS will go into performance management mode and cause your iPhone to slow down. When this happens, the tool will state “This iPhone has experienced an unexpected shutdown because the battery was unable to deliver the necessary peak power.
Performance management has been applied to help prevent this from happening again”.
Users then have the ability to manually disable performance management, but won’t be able to enable it again on their own. It will only turn on again if iOS encounters another battery problem.