It is only when the charge level lowers that the recharging mode is activated and the charge is restored to 100%. Using the "Optimized Charging" feature, the battery is charged to 80% and then shut off. After waking up in the morning, the user is usually ready to grab the phone out of bed and charge it to 100%. Click here to read more: https://repairbuy1.medium.com/how-to-increase-iphone-battery-life-without-mobile-repair-online-ec448532f820