March 27, 2012: here's more from Apple, regarding Apple IOS devices and batteries:
So, here’s how things work: Apple does in fact display the iPad (and iPhone and iPod Touch) as 100 percent charged just before a device reaches a completely charged state. At that point, it will continue charging to 100 percent, then discharge a bit and charge back up to 100 percent, repeating that process until the device is unplugged.
Doing so allows devices to maintain an optimum charge, Apple VP Michael Tchao told AllThingsD today.
“That circuitry is designed so you can keep your device plugged in as long as you would like,” Tchao said. “It’s a great feature that’s always been in iOS.”
I think I am reading this correctly. Under some conditions, one can get 25 hours of battery life out of the new iPad.
A few other tidbits related to the device's battery are gaining some exposure, information which may help users plan how they use their iPads. First, a report from AnandTech addressing battery life has been gaining renewed interest for its revelation that users running a Verizon iPad in personal hotspot mode can see as much as 25 hours of battery life to provide connectivity for their other devices. That number has also been confirmed by The Verge.The advertised duration for a fully charged iPad is ten hours.
Again, I could be reading this incorrectly, but that's what I'm reading. That might explain why it takes longer to charge up the new iPad also.