One of the triumphs of the newly unveiled iPad is the fact that despite having a much faster, quad-core processor and a Retina display, Apple says that it will still deliver 10 straight hours of battery use on just one charge, and 9 straight hours even when the LTE radio is in constant use. How can this be, you might be wondering?! Well, according to PhoneArena, the answer lies in the fact that the new iPad has a 42.5Wh battery, which is almost twice the capacity of the iPad 2’s battery, which is 25Wh, and the reason for the new iPad being a tiny bit heavier than the iPad 2. Many people thought the fact that the new iPad was rumoured to be getting a battery with a higher capacity would mean that it would actually have an extended battery life beyond the 10 hours of the iPad 2, but given that the new iPad’s battery actually has a lot more to do, for once, maintaining the status quo as far as battery life is concerned is no bad thing.
Source: iPad 3 can run for 9 hours straight on LTE. Here's why