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Breathe new life into your laptop’s battery

With these tips, you can keep your aging battery working for years (and for hours between charges).

By Lincoln Spector / Wednesday, July 28 2010

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Eventually and unavoidably, laptop batteries die. And they don’t obey Moore’s Law: next year’s batteries are unlikely to last twice as long as this year’s. Battery technology may improve a bit over time, but don’t expect major battery breakthroughs in the near future.

Proper care can delay the inevitable. With luck, your battery could last until you need to replace your aging notebook (perhaps with a laptop that has longer battery life). I’ve also included a few tips on keeping the battery going longer between charges, so you can work longer without AC power.

Don’t run it down
Squeezing every drop of juice out of a lithium ion battery (the type used in today’s laptops) strains and weakens it. Doing this just once or twice won’t kill the battery, but the cumulative effect of frequently emptying your notebook’s battery will be to shorten its life span. (For the one exception to this rule, see “Heal a sick battery” on the next page.)

The good news is, you probably can’t run down the battery, anyway – at least not without going to a lot of trouble. Most modern laptop models are designed to shut down before the battery is completely exhausted; in fact, both Vista and Windows 7 come with a setting created expressly for this purpose. To see it, click Start, type power, and select Power Options. Click any one of the ‘Change plan settings’ links, and then click the Change advanced power settings link. In the resulting dialogue box, scroll down to and expand the Battery option, and then expand Critical battery level. The setting you see there will probably be about 5%, which is a good place to leave it.
For its part, Windows XP offers no such native setting, although your laptop might carry a vendor-supplied tool that does the same job.

Myth: You should never recharge your battery all the way.

Considerable controversy surrounds this issue, and I have interviewed experts both in favor and opposed. But I’ve come down on the side of recharging a notebook’s battery all the way. The advantages of leaving home armed with a fully charged battery – you can use your PC longer without AC power – are worth the slight risk of doing damage.