Help Slow Charging. Help ASAP!!

[ValentinJ]

Okay so before you start bombarding me with the "its your USB wire get a new one" its not. I've tested the phone (Samsung mega 6.3 at&t by the way) with various wires with different voltage. It all comes to the same end point a very slow 300mA per second charge. I have no idea why, all I know is its not the battery or the wire. So is it an internal thing I need to fix or is there a easy fix to this?
HELP MEH!!!

 

[mikedt]

Could be the phone. Is the Galaxy Mega supposed to have fast charging? I know some Samsungs do, like the S4 and S5, but that's only with the Samsung specific chargers, and not generics, PC USB ports, etc.