I bought a S4 from a retailer specializing in graded phones. I bought a Grade A Samsung S4 and the condition is perfect ie no scratches, plastic stick around the edges etc but came with only phone and no charger. My problem is that I am using the charger and usb cable from my previous S4, the one with the 2A plug however, I'm only getting 460mA from it, so charging is extremely slow. I've tried another usb cable and also tried both cables with a HTC 1A charger but everything gives a reading of 460mA. In battery it says charging (USB) so it's not recognising that the usb is plugged into a mains socket. I've tried my brothers generic micro usb wall charger which shows as a 1200mA current and charging (ac) so i'm kind of lost as to why it's not charging properly with the official charger