Why is my Samsung galaxy s3 battery draining when I charge it?

[AC Question]

Ever since I got my Galaxy S3 phone fixed from being in a bootloop, the battery is weird. I'll connect it to my charger and instead of the battery % increasing it will decrease. I've tried turning it off to let it charge and when its at 100% I'll turn it on and it'll drop to 3%. What's the problem and how can I fix it?

 

[B. Diddy]

Welcome to Android Central! The battery might be failing--try a new one.