Why Can’t We Get an Accurate Battery Life Test for Laptops?

Why Can’t We Get an Accurate Battery Life Test for Laptops? - Bits Blog - NYTimes.com: "Some of the companies making and selling computers are contemplating a way to give people a more accurate idea of how long the batteries in their devices will last. I know, I know — accuracy and battery life measurements don’t usually make it into the same sentence. The long battery lives promised by computer makers never seem to actually occur."