USB charging in host mode Possible Duplicate:
  Using an OTG cable while charging  




Recent versions of Android allow USB to operate in host mode.  But is it possible for them to be powered/charged via that same USB port while operating in host mode?
There is only one USB port for USB OTG (which not supports USB hubs if I remember well) AND charging the phone. So you will have to make a choice. To my mind this is the main problem with USB charging. Phones are used to having a unique port and you have to choose what you want to do with this only port.