We had numerous requests from people to record the talk that Justin gave on his 7 years of firsthand experience with ebike batteries. Unfortunately our video recording skills came through poorly at best, but for those willing to watch 2 hours of grainy footage to understand some of the challenges of dealing with rechargeable batteries, it all begins here: http://www.youtube.com/watch?v=5frJlJiCS34&feature=related

Or you could follow on the endless-sphere thread.

We've also made the original slide images available as a PDF document.