Why does my phone battery warning keep popping up?

[AC Question]

So, for the past two days my phone charges extremely slowly, like 35% in 7 hours. The battery life drains extremely fast, even when its off. When it is charging, the "battery critically low" warning keeps popping up over and over again, and it turns the phone on when its off. I have tried charging it when its completely shut off, I checked the condition of the battery (clean and normal), and I cleared the cache. I even tried a new charger and plug. Can anyone help me out with this problem? Any help will be greatly appreciated.

 

[belodion]

Welcome.

Perhaps you need a new battery?