Arduino Mega ADK & Android Phone

Hi everybody,

We are doing a wheelchair data-logging project and we are thinking of having the Arduino Mega ADK to continuously send data to the Android phone. We have two options - 1) send it over Bluetooth, or 2) send it over a USB connection. The problem with Bluetooth is that we do not know how much it drains the battery. So, if we choose the USB option, we are wondering whether the USB connection would be automatically re-established after a reboot of the Arduino or the phone?

One more question - does anybody know of a commercially available battery or system that can be re-charged via an AC adapter? We are also thinking of having one battery to power both the Arduino and the phone so only one thing needs to be charged per day instead of disconnecting the phone to charge it separately.

Thank you very much for your input.