Update: Did Amazon magically change the battery life of the Kindle? Not really. It's all about the assumptions included in calculating battery life for e-readers and making claims on them.
Overnight it appeared that Amazon had some pretty strong magic at their disposal because they've bumped up the battery life of every single Kindle out there from one to two months by doing ... nothing.
Amazon has long claimed in ads that the latest-generation Kindle has a battery life of one month. However, following the launch of Barnes & Noble's new Nook ebook reader, which has a battery life of two months (B&N say it has the 'longest battery life of any eReader'), Amazon has now upped the Kindle battery life to the same two months ... all without touching the battery or the software.
What happened? Barnes & Noble assumes you'll read your Nook a half hour a day. The previous assumption by most e-reader companies was that you'd read one hour a day.
So what's going on here? Bottom line, it's a 'playing with the numbers' game. All Amazon has done here is changed the way that it measures typical usage to match what Barnes & Noble did. Having extensively used a Kindle I'd say that the claim of one month battery life was pretty close to the mark and that two months, even with wireless switched off, is drifting off into fantasy land. But that all depends on what your definition of extensively is.
This knee-jerk reaction goes to show how threatened Amazon feels by B&N's new Nook. And if Amazon isn't threatened it's clear the competition is intense.
[UPDATE: It seems that Amazon.co.uk are still somewhat confused by the battery life change with several references to one month battery life still present:
I'm sure Amazon.co.uk will get the message about the updated battery life ... eventually.]