Anandtech published Samsung Galaxy S 4 Qi Wireless Charging Pad and Cover - Mini
A quote from the article:
For a while now, wireless charging has been slowly gaining momentum, and one of the phones that includes support is Samsung’s Galaxy S 4 (SGS4). For the past week, I've been using a review unit of Samsung's wireless charging accessory kit for the aforementioned smartphone which includes both a Qi compatible wireless charging pad and battery back.Samsung Galaxy S 4 Qi Wireless Charging Pad and Cover - Mini Review @ Anandtech
Using the wireless charging accessory is simple you remove the stock battery back, snap on the new one, and plug the wireless charging pad into the Samsung charger that originally shipped with the phone. This last point is critical, as the wireless charging pad requires the 2 amp charger that Samsung supplies with the SGS4. I've touched on charging in the past before, but this charger includes the 1.2 V signaling across the D+ and D- pins which signals 2 amp (tablet-class) compatible charging to Samsung devices, like the charging pad. Using a normal BC 1.2 compatible charger won't work, as that specification only stipulates up to 1.5 amp delivery on its dedicated charging port.