The iPad 3 does take longer to charge. It has a significantly larger battery than the iPad 1 or 2, and needed it. The retina screen takes a lot of power. It's also the reason that the iPad 3 is one of the very few devices Apple has made that is thicker and heavier than older models. The iPad 4 and iPad air come with higher wattage chargers to compensate. Something Apple failed to do for the iPad 3, one of the little things that slipped by their design team in what was a big hardware upgrade. If the iPads were put back in the boxes in sleep mode (rather than off), they would have shut down eventually; but the small 10%-5% charge would not have lasted six months. One of the reasons Apple makes an iPad shut down automatically at low battery levels is to prevent a total discharge of the batteries, which can permanently damage them.