I'm using an asus transformer tablet with an ADK board and everything is working well apart from the powering of the tablet. The ADK board isn't capable of supplying of enough current to keep the battery charged. I would like to separate the power supplies so that the tablet is supplied via its own original charger and the ADK is powered by a separate 9v supply. I bought a USB Y cable which has 2 USB A plugs and 1 USB A socket but this doesn't work as the tablet no longer sees the ADK board.
Any ideas of how to connect this ? I have USB connectors and could make a custom cable if required