By default, Snapchat uses a Wake Screen feature that illuminates your smartphone as soon as a notification hits your phone. Unfortunately, this feature can contribute to battery drain, as it does leave your screen illuminated for a few seconds at a time.
This article will teach you how to turn off Wake Screen on Snapchat. Once this feature is disabled, any Snapchat notification will be shown upon manually waking your device's screen.
Prevent Snapchat from Waking Your Phone
Launch the Snapchat app, and tap the Settings menu (represented by a gear icon):
Scroll to the Advanced section, and tap Notifications Settings: