It does not make much difference what you are using the iPad for, this gadget is going to be completely useless when the battery runs out and this is more likely to happen when you are out because of it running on the battery. Fortunately there is this case with built in battery pack that is capable of doubling the battery life of the iPad, this means the device can go all day long, literally!
These are the features and specs for the iPad case with double battery life;
The battery effectively doubles an iPad’s battery life, providing up to 24 hours of continuous video playback or up to 12 hours of industrious use (highest brightness, loudest volume, enabled Wi-Fi, and graphics-heavy games). The included cable connects the battery to an iPad’s charging port while the iPad nestles inside the cover. The case protects an iPad on all four sides yet keeps controls exposed for easy access. The cover adjusts for laptop use while typing and browsing or upright use for watching movies. Plugging the battery into a computer or AC using the included USB cable results in a full charge after nine hours. 9 3/4″ L x 9 1/2″ H x 1/4″ D. (3/4 lb)
Price at $149.95
Source [Hammacher and Schlemmer]