Kindles Get 85 Percent Battery Power Boost On Wireless has an early Christmas present to Kindle purchasers: 85 percent more battery life if you're going wireless.

The company announced today that the battery would last up to seven days, even if the wireless is turned on. That's three days more than the previous battery, which lasted four days. The battery life with the wireless turned off remains the same - up to two weeks.

Amazon's been working for six months on firmware improvement and testing the battery with wireless to get to this point.

Now, before you get all ticked off because you bought your Kindle yesterday, Amazon said those battery life improvements will be available for you by way of a firmware update to be automatically delivered via Whispernet wireless.

In addition to the increased battery life, the six-inch Kindle also is getting a native PDF reader. This will allow customers to read documents in their original format, without having to be converted in order to be compatible. This update also is available to previous purchasers via a Whispernet wireless firmware update.

The PDF reader will work in much the same way as the previous conversion did - e-mail the PDF to your Kindle e-mail address. If you want it converted, type "Convert" in the subject. If you don't, it'll stay as a PDF. They can also be transferred into the Kindle using a USB connection.

The Kindle has become the No. 1 bestselling product on Amazon since the latest release, which has 3G capabilities, enabling users to use cell phone networks rather than just hunting for a wireless connection.