A, open the settings application on the iPhone;
B, select "battery";
C. Click "Battery Health";
D on the battery health screen, you will see two indicators related to battery health: "maximum capacity" and "peak performance".
Any new iPhone will have a perfect battery with a maximum capacity of 100% or close to the maximum capacity of 100%. Obviously, the newer the iPhone, the better the shape of the battery should be. If you don't see the "Battery Health" section in the iOS settings, your iPhone is not iOS 1 1.3 or later, or it is not an iPhone. Tips: At present, the iPad does not support the battery health function.