Apple uses a lithium battery, which can guarantee about 80% capacity after multiple charging cycles. Apple pays more attention to 80% battery capacity, which they think can guarantee basic battery life. If it is lower than this good number, you need to replace the battery. Generally, a normal Apple mobile phone will not start. When your Apple phone is turned off unexpectedly for the first time, performance management will be automatically enabled. Mobile phones automatically manage performance peaks, such as frequency reduction, to prevent accidental shutdown.
IPhone uses a lithium-ion battery, and the maximum capacity of the battery will inevitably decrease with the increase of use time. The life of each battery is basically determined after leaving the factory, which is determined by the number of charging cycles. Generally speaking, when the number of charging cycles reaches 500 under normal use, the peak capacity of the battery should be 80% of the initial capacity. It is inevitable that the battery capacity will decrease, but there is a saying that it is necessary to reduce the speed and take preventive measures to make the battery last longer.