My phone battery will not charge properly. Should I buy a new battery for my Android phone?

[AC Question]

I have left my phone on charge for hours and at the moment I can only get 4 per cent charge.

 

[UJ95x]

Welcome to AC
What device are you using? Are you charging with the stock cable and wall plug?

Sent from my Galaxy S4 running Lollipop 5.0.2