Bettery not changing full when poweron

[AC Question]

My SamsungGalaxy A8 is not charging when power on ,if I charge it with power off it get charge 85 % .Please help me somebody.

 

[B. Diddy]

Welcome to Android Central! Are you charging from a wall outlet or a computer USB port? When you're charging while the phone is on, are you actively using the phone and doing something very processor intensive (like playing a game)?