You Have Constant Notifications
Apps will send notifications to your Lock screen on your iPhone, but a problem arises when you have too many apps sending notifications this way. If you get frequent messages, emails, social media updates, or more, then your iPhone may turn on the screen every time to alert you. Turning on the screen so often is a significant drain on your battery life, and many of these notifications aren’t even necessary. Head to Settings and take a look at which apps can send alerts this way. Turn them all off except the ones you really, really need – usually only one or two apps like Phone and Messages.