We are shooting with our new HPX500 and wanting to offload clips onto drives for backup. Just wondering if anyone has used 2.5" bus powered external drives like the Maxtor Onetouch III Mini? We are going to be out in the wilderness for the day... only battery power around, and want to back up to our laptop and to the drives. Is this a safe way to go? Thinking of backing up on 2 Maxtors in the field... ? Just haven't had much experience with the USB powered drives.