Battery or Actual Phone problem?

[JesseBeers]

My uncle recently gave me his old Samsung Galaxy s3 which he has not used in forever. I got the phone connected yesterday and everything works great. The only problem I noticed is that it does not charge past 50%, and it also takes forever to charge. It can be plugged in for hours and it only goes up by 5-10%. I've tried different chargers that actually charge my other phones completely. Today at work I tried using my coworkers battery which was at 80% (Samsung s3 battery) I put it inside my phone and it only showed 3% when the battery was actually almost fully charged.
What do you guys think the problem might be, and is it fixable?
Thanks in Advance.

 

[Kelly Burby]

Well, it looks like there might be some problems with the hardware, I would suggest you to go for the nearest support centre for fixing it up, rather than looking for answers in the forums.