Hello. I was wondering what the maximum size of a flash drive or external hard disk that would connect to an SP3 without an external source of power. I tried connecting my WD 500GB external HD to my SP3 but I needed a Y-cable to connect to the external battery because the USB 3.0 wasn't providing enough power. Would a 128GB connect to an SP3 just by itself? Or is it 64GB or even 32GB?