How to maximize battery life

Poor battery life can tarnish your mobile experience. Fortunately, there are all sorts of easy ways to make a laptop battery last longer. Incorporating one of these power-saving habits alone might not result in a big change, but if you practice key ones faithfully you should see an improvement of anywhere from 15 minutes to a couple of hours, depending on your starting battery life.

What to look for in a new laptop

Battery life has improved a lot in the last 20 years—but not to the point where laptop users can take good performance for granted. Shopping for a new laptop is the perfect time to make sure you get the kind of battery life you need. Will the laptop stay plugged in most of the time on your desk? If so, battery life might not matter as much as some other feature, such as a big hard drive. But if you need to get a lot of work done on trains, planes, or coffee shops short on wall sockets, keep the following in mind.

  • The bigger the screen, the shorter the battery life, in general. In fact, Microsoft estimates that 43 percent of a laptop's power goes to the screen. [link to chart: http://blogs.msdn.com/b/e7/archive/2009/01/06/windows-7-energy-efficiency.aspx]. A laptop with a 15-inch screen that lasts four hours on one charge would be considered a good performer. However, a mini-notebook with 10-inch screen might last twice that long.
  • When comparing laptops with the same screen size, pay attention to battery specifications. All laptops come with rechargeable lithium-ion batteries, but not all li-ion batteries are created equal. Higher numbers usually mean a longer lasting battery, thus a 9-cell battery will endure longer than a 6-cell, and batteries with higher mAh (milliamp hour) or WHr (watt hours) numbers are more desirable than batteries with low numbers.
  • Take advertised battery life with a grain of salt. Though some vendors are switching to more realistic tests, others still achieve their battery life numbers by turning the screen to the dimmest setting and allowing the unit to run down without using the keyboard or drives. Subtract about 25 to 30 percent from the vendor estimate for a battery life based on real-world use.
  • Stock up on RAM. More RAM gives your laptop more space to work on files without swapping data to the hard drive as often, thus saving power.
  • Buy the extended-life battery. If the vendor offers an extended-life battery for a few dollars more, by all means choose the better battery. Just beware these larger batteries add up to half a pound to laptop weight.
  • Forget keeping a second battery. Buying a second battery to pop in when the first one goes might sound like a good idea, but will you really want to lug around an extra battery for the rare emergency when an outlet can't be found? Probably not.

Good power habits stretch battery life

You can expect a laptop battery to perform at its peak for only one to two years before it begins to wear out and you'll need a replacement. Until then, make your laptop battery last as long as possible by practicing as many of these power-friendly habits as possible.

First, take good physical care of your battery. That means no extreme temperatures. Overheated laptops make the system and thus battery work harder, so make sure air vents aren't blocked. If you like using your laptop on your lap, buy a laptop cooling pad for about $30. (Your overheated lap will thank you, too.)

There are at least a dozen other ways to save battery life—if you're willing to sacrifice a few conveniences. Most of these changes to settings can be made in the Power Options utility in the Control Panel:

  • Dim the lights. Screens cranked up to their brightest setting and backlit keyboards suck power. To adjust screen brightness on the fly use the Ctrl-Fn keyboard combination.
  • Opt for the deeper hibernate mode. Sleep is fine for short work breaks but hibernate is better when you'll be away for a while. Don't use the lid to activate hibernate—Windows often hangs and you'll come back to a still-running overheated unit. Use the power or sleep button instead.
  • Shut off music and movies. You're supposed to be working anyway, right?
  • Unplug peripherals and enable the USB selective suspend setting. The latter tells your laptop it can turn off USB ports that haven't been used in a while.
  • Turn off Wi-fi when you don't need email or the Internet. Most laptops have a disable button to save you the hassle of changing software settings.

Don't forget to ask your laptop to notify you—another easy Power Option setting—when the battery gets low so you can save your work.

Even when you scrimp and save power, batteries never seem to last long enough. But if you follow these tips, you can work a little longer before scrambling for an outlet.

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