It only has a 4,000 mAh (15 Whr) battery, smaller even than Nexus 7's 4,300 mAh battery, and considering it also has a much larger 12" screen (more than twice screen area), the battery life would also be smaller than Nexus 7.

Nexus 10 has a 9,000 mAh battery, which is also used to compensate for the 2560x1600 resolution. iPad 3/4 has 11,500 mAh and it's pushing 1 million fewer pixels for comparison's sake.

But I agree, Google needs to rectify this in next year's ARM Chromebook. They need to use a battery large enough to hold for 10h (and hopefully maintain, or lower the price). If they use this big.Little chip from Samsung next year, it might be easier to achieve that:

http://androidheadlines.com/2012/11/samsung-8-core-big-littl...