The new iPad features a significantly larger battery over the iPad 2, packing a 42.5-watt-hour battery compared to the old 25-watt-hour battery. As a result of the increased battery capacity, the new iPad takes longer to charge. But in a new discovery, when the iPad does reach 100%, it doesn’t stop charging.
DisplayMate examined the new iPad and its battery capacity as well as charging habits. Dr. Raymond Soneira found that when using the included power adapter, the new iPad continued to draw 10 watts of power for around an hour after reaching 100%. It’s possible that the iOS battery indicator is reporting an inaccurate value.
Meanwhile, DisplayMate confirmed the longer charging times needed with the new iPad thanks to the larger battery. The cause of that increased capacity is the new Retina Display, along with 4G LTE connectivity. The display makes use of Super High Aperture panels, which requires more LEDs to push through the same amount of brightness, increasing battery consumption.
Current LTE chipsets are also known to consume large amounts of power over traditional 3G chips, although this won't be an issue for those in counties without LTE connectivity. DisplayMate concluded that screen brightness plays a large role in the amount of battery life you can squeeze out of the new iPad, with video playback roughly averaging 11.6 hours if brightness is set at 50%.