Laptop batteries: don't worry, they'll be dead soon enough

Slate’s Farhad Manjoo ventures into the murky world of rechargeable battery life with the article “How To Charge Your Laptop,” subtitled, “Four essential tips for extending the battery life of your computer, cell phone, and every other gadget.”
The gist: keep your battery charged between 20 and 80% of capacity, keep it cool, and remove it when it’s charged and you are using the computer while it’s plugged in.

I’m not quite sure what the fourth essential tip is. It might be, if you are not going to use a battery for a while, charge it to the 40% level before storing it so it doesn’t self-deplete.

Manjoo got his advice from Isidor Buchmann, the CEO of Cadex Electronics (a company that makes battery-testing equipment) and proprietor of the Battery University Website for battery enthusiasts and engineers. Buchman lets Manjoo know that when it comes to battery life, “There is not too much to discuss.”

In fact, any battery is destined to become a useless piece of junk, probably sooner rather than later, no matter how closely you attempt to keep it within the 20 and 80% range by monitoring the battery guage, which itself may be close to a piece of junk. As Buchmann forthrightly explains to Manjoo, “The technology to measure batteries [with respect to laptop built-in power meters] is just not that good. We can’t do it. It’s that simple.”

Manjoo’s article doesn’t even mention the MobileMark benchmark. The latest news of MobileMark is that it’s compatible with Windows 7, even if it doesn’t have much to say about useful battery life per charging cycle and total longevity.
My advice? If you often need to run your laptop on batteries (you can’t score an airplane seat with an electric outlet, you’re live blogging a 90-minute speech, or you can’t get to the Internet café early enough to plug into the couple of outlets available to customers), budget for a new battery every six months to a year.