That's exactly what I do with my new Acom 160GB drive; it came with a USB cable with an extra power-only adapter included, so I just plugged it right into my NOMA RX4 battery pack (which looks like your one, just white). The drive powered up. I then plugged the powered-up drive into my N800, and it just worked. I also have one of Jolous' N800 OTG adaptors so it just plugs and connects, and I don't need the F-F adapter either. Sometimes, I have to plug the drive in twice to get it to work, the first time the N800 doesn't even respond to the plug-in.

It is amazing to be able to put EVERY mp3 that I have, every digital photo I have ever taken, etc., on a hand-held drive and still have space left over...