The battery update is available immediately through Apple's automatic Software Update function, or can be downloaded from the company's site manually. Apple has promised to give a new, free battery to users if the update does not fix the performance issue on any individual machine, even if the computer is past warranty.

Limited Impact

Apple noted that the problem with the affected batteries is that they do not charge when the computer is connected to a power source. The batteries in question are found in notebooks sold between February 2006 and April 2007, and have been distributed worldwide.

In addition to difficulties with charging properly, some affected batteries reportedly also have had other problems, such as visible deformities, a low charge capacity, reduced runtime, and lack of recognition in the Finder menu bar. In the menu bar symptom, an "X" appears where the battery icon would usually be shown.

In releasing the news about its batteries, Apple also emphasized that it does not expect the battery glitch to have any impact on its earnings statements. The connection between notebook sales and earnings is especially important for Apple right now, because the company noted last week that its 36 percent increase in sales was driven primarily though sales of notebook PCs.

Sputtering Performance

The difficulties associated with Apple batteries come just days after a company subsidiary of Acer announced a recall for 27,000 batteries in the U.S. Other computer manufacturers, including Dell, Sony, and Toshiba also have been struck by battery problems recently. Most notably, Dell had to recall over four million lithium-ion batteries after several notebooks caught fire as a result of battery malfunction.

It is likely that there will be additional laptop battery recalls in the future, analysts have noted. But overall, improved battery performance has been one of the factors driving more laptop purchases, said IDC analyst Richard Shim in a recent interview.

"Longer battery life and better overall performance have been luring new buyers," he said. "These type of factors are setting a pace for notebook adoption that's bringing closer the day that notebooks sell more than desktops in the U.S. market."