My samsung s3 will say 100% but when i unplug it it goes down to 60%. How can I fix it?

[AC Question]

I tried changing the battery but it still does the same thing, and when it is charging it does it very slow. I checked the usb port and that's also fine so I really think there's something wrong with my phone

 

[spagman]

Yes, I would agree... I would say that the charging IC chip is bad (hardware).

If you can find somebody that works on phone hardware have them replace the chip.

Sent from my SAMSUNG-SGH-I317