I asked them....they gave a speady reply for this time of night....
Hi Luke,
No, they will require power when not plugged into usb, so in that sense they can't be used “ipod” style, however they both have mains adaptors with them but I see no reason why you couldnt use a powerpack to power them provided it was the correct voltage/amperage.
I guess the thinking is that you will need a mains supply to power a tv so it can be used to power the HDDivX players as well.
If you need any more info let me know.
Best
Simon