Since the 10.1 was able to work with the external HDD with an external battery supply, I thought the Note 2 would be more than able to handle it as well. I WAS WRONG. The Note 2 will pop a device error hdd corrupt needs reformat message. It would also crash the Note 2's USB driver at times and require a reboot.
Unfortunately, the Note 2 will require a power supply plugged into an outlet to work. The external battery trick will not work with the Note 2. Although, I'm not sure if a higher mAh battery would have handled it better. I am using a 5000mAh external battery with the external HDD.
Though, if that was the case, I would have expected a high powered device error and not a corrupt drive error. So it looks like it won't play nice with an external battery powering an external HDD.
Another side note, I plugged in a powered 7-port USB hub. I was only able to get a mouse, keyboard and 3 USB sticks to work at the same time. It failed upon inserting a fourth USB stick. It would exhibit strange inconsistent behaviour when the fourth stick is placed in. In the extreme case, it hard crashed the Note 2 which required a press and hold of 8 secs on the power button. The Note 10.1 on the other hand handled it all pretty well.
I'll probably play around with the powered hub later on just for the heck of it. Just curious as to what the Note 2 is capable of. Definitely not as strong as the Note 10.1, that's for certain. Maybe Sammy was a little more stringent with regulating power draw/drain on the Note 2. I have a wired xbox 360 controller I'm dying to see work with keyboard and mouse. LOL.