PCWorld: Dr. Raymond Soneira of Displaymate Technologies has a message for new iPad owners: keep the tablet plugged in for a while after it says the battery is fully charged. In his tests, Soneira found that the new iPad continued to charge for at least an hour after the device claimed to be done charging.
Soneira also confirmed that the new iPad takes about twice as long to charge as the iPad 2. The new model's improved specs required a larger battery, and that means more charging time. According to Soneira, users will find the optimum balance of battery life (about 11.6 hours) and readability if they keep the display brightness slider in the middle.