Charging doesn't seem to be happening to iphone5s plugged into hdmi and usb to FireWire with Apple connector

Any thoughts.

I am assuming you are talking about the apple digital a/v adapter, with lightning connector. I found the nex did not charge my phone very well, so i hooked up the lightning to usb cable that goes into the adapter to car charger instead of the head unit.  This also leaves the usb ports on the nex open for other input devices like usb thumbnail drives or solid state drives.