Yesterday I downloaded (for better worse) somewhere over 400 items. My PW is still indexing them by the way... I waited till the battery was nearly discharged, then plugged it in to the wall and charged it all the way. By tonight the battery was nearly completely discharged again. I'm not sure if Active Content uses significantly more battery than regular books, but I did spend some time playing a word game as well as reading.
It will be interesting to see how the battery does once all the indexing is finished. Has anyone noticed whether a lot of books on the device discharges the battery quicker in and of itself, or is that simply an indexing issue which will go away after all is indexed?