I doubt that a battery would work very well. Using a battery would have you manually turning the unit on and off every night or more like pluging in and unplugging the battery. I would believe that the TX/RX would make short work of a standard 9V battery. Anyway you look at it, the unit will require an ethernet cable plugged into it so it will never be "completely" wireless. There has been discussion of supplying power units like these by using one of the unusd pairs in the ethernet cable but as RJ pointed out, there could be issues doing that.