Because the battery health is less than 80% loss, the battery life will feel obviously different. It will also affect the battery life of the iPhone. Which leads to the problem of frequency reduction of the mobile phone. In terms of battery health, the maximum capacity of 100% means that the battery has almost no loss. The lower the capacity, the shorter the battery can be used after it is fully charged. Generally speaking, if it is less than 90%, the sense of use will become worse. If it is lower than 80%, you can consider changing the battery.
For iPhone 6 and newer models, iOS 1 1.3 and later versions have added several new functions, which can display the battery health status and suggest replacing the battery when necessary.
Extended data
The Battery Health screen contains maximum battery capacity and peak performance capacity information. ?
The maximum battery capacity measures the battery capacity relative to the new battery. With the increase of battery chemical aging, the battery capacity will decrease, resulting in a shorter battery service time between two charges. Depending on the length of time between iPhone production time and device activation time, the displayed battery capacity may be slightly lower than 100%.
Normal batteries operate under normal conditions. When the number of charging cycles reaches 500, the battery should be able to maintain 80% of its initial capacity at most. One-year warranty includes service guarantee for defective batteries. If it is not within the warranty period, Apple can provide battery service for a fee.
IPhone official website -iPhone battery and performance.