destinyland writes "Amazon just doubled the reported battery life for their Kindle digital readers — but they did it by cutting the estimated daily usage in half. Monday Amazon's competitor Barnes and Noble released a new touch-screen version of their Nook reader, and C|Net notes that apparently Amazon 'took issue with how its competitor was calculating and presenting its battery life numbers.' When Barnes and Noble claimed that the Nook's charge lasted twice as long based on a half hour a day of usage, Amazon simply recalculated the Kindle's battery life using the same formula. By Wednesday, Barnes and Noble was insisting that the Nook's charge still lasted twice as long as the Kindle's. 'If that's true, then Barnes and Noble mangled the launch of their touch-screen Nook,' reports one Kindle blog, 'by botching their description of one of its main selling points.'"