6.5V * 1.0A = 6.5W
5.0V * 1.2A = 6.0W

The N800 battery will be pretty worn down by now. My own N800 battery's capaity is about 700mAh today. My N810's original battery is at about 600mAh, and the replacement original Nokia battery had been on the store shelf so long it only gives 900 mAh.