Extending Your Laptop's Battery Life–Revisited


The other day, in my post 9 Ways to Get Better Battery Life,  I detailed a number of steps you can take to greatly extend the time you spend with your notebook unplugged. As I mentioned there, quite a few of the tips collected came from readers of an earlier post I did, many of whom made the point that simply turning brightness down on your display can have a radical impact on battery life.

Today, in a post from Microsoft engineers working on energy efficiency for Windows 7, there is substantial evidence shown that this fairly well-known, but rarely followed tip does indeed make a big difference. The post illustrates which other steps make a difference too.

The engineers at Microsoft produced the following pie chart showing where the energy goes when modern laptops are running (hat tip to Lifehacker Australia for flagging the post):

Sure enough, nearly 50 percent of the energy drawn by your laptop goes to the display. It really does make sense to turn the brightness down when you’re working on things like documents and e-mail for extended periods. These Microsoft engineers have a compelling reason to be getting this specific about analyzing this for Windows 7, and that is that Windows Vista has been slammed continuously for its reckless draws on battery life.

It will be good news when modern operating systems of all stripes self-adjust and offer users straightforward ways to optimize their systems to conserve battery power. Hopefully Windows 7 will do a much better job of doing this than Vista did.

In my post from the other day, there are also other tips that line up with the graphic from the Microsoft engineers. Hard drive access and network tasks take up reasonably significant amounts of energy, so defragment your drive for faster access and if you don’t need Wi-Fi and other network connections for an extended period, hop off. Also, your processor sucks a lot of juice, so be very wary of highly processor-intensive tasks such as streaming lots of video.

Still, these ideas are less of an issue than how you treat your laptop’s display. If you’re a frequent user of hotspots and an often untethered portable web worker, turn the brightness down when you don’t need it for extended periods. It’s simple, you probably already knew about it but don’t do it, and it works.



And the remaining 10% that is not on the chart is used to summon the dark mystical forces that make the other stuff work?

Anthony Williams

If you’ve got access to an external monitor, it’s worth using that. I know that in this case you’ve likely got access to a power supply too, but sometimes it’s a good idea to run on batteries even when there is AC power available. In fact, DELL customer service advised me that it is better for battery life to run your batteries down completely, and then charge them up again, rather than run off mains all the time.


I can tell you that if you use a cellular network card to get access to the Internet using a cellular connection, that card will eat up the battery very fast. When I am in airports and want to connect, I do connect, then disconnect to preserve battery life for the flight. Those cards eat up battery power faster than the LCD!


In that case, there should be another wedge labeled “Other”, so there is no distortion (unintentional or otherwise) of the data in the chart.


That pie chart only adds up to 90%. This chart has appeared in a dozen places already and nobody has mentioned anything about this violation of the basic premise of a pie chart, and the only reason to use one: that the parts add up to the whole.

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