If battery on samsung laptop is only charging to 80%, this is because Battery Life Extender function in Samsung Control Center is enable. Battery Life Extender sets the maximum battery charge level to 80% in order to extend the life of laptop’s battery. Follow below steps to disable Battery Life Extender in order to fully charge laptop’s battery.
Windows 10
Step 1: Open Samsung Settings and then click Power Management.
Step 2: Under Battery Life Extender + section, slide slider to OFF.
Windows 8
Step 1: Open Samsung Settings and then click Power Management.
Step 2: Click Battery Life Extender tab.
Step 3: Slide slider to Off.
Windows 7
Step 1: Press Fn + F1 keys on keyboard to open Control Center.
Step 2: Click on Battery Life Extender.
Step 3: Slide slider to Off.