Battery Life Time Warp

"The Tested.com article got me thinking about battery life claims we see on PCs of all shapes and sizes. Why is it that HTC, Apple, Motorola and the rest of them can come within spitting distance of what people experience when using their smartphones as they were intended to be used, but mobile computer companies feel the need to sprinkle their battery life claims with a sack of fairy dust? When’s the last time you were able to see anything close to the claimed battery life on your notebook, netbook or Tablet PC?"

Cell phone power usage tends to be much less variable than full fledged computers, where power consumption can easily triple depending on what you are doing.  Of course, as smart phones are getting much more complicated and powerful, we are seeing the same range in battery life in them as we do laptops.  However, the point is valid.  Battery life claims on PCs are far too optimistic in a real world scenario.  I wish I knew how they calculated their numbers as it seems like you can only have the computer turned on, not doing anything, to come close to manufacturer claims.  With people demanding more of their computers, from watching videos to playing games, all very power draining activities, the are going to find that the alleged 10 hours of battery life will fly by in what seems like 4.