Folks, I do not think the battery works with the device to charge, in regards to when it shuts a charge off. The battery handles that, unless the Inc has some new handshake technology. Even if there was some form of "talking" between the battery and Inc for charging, it would be low level, on & off process. USB power for charge is not a hgh level software issue.
It is a 1300mah battery powering 3.7" high res display, 3G, Android and the social apps, audio, games, maps, gps, wifi, etc. Even if just some of these things on, the battery is just 1300mah.
iPhone is mentioned a lot in comparisons, but smaller screen, lower res, no multi-task or Flash in browser.
The 2150mah battery will probably be the biggest accessory seller in VZW history.