Apple Computer has initiated a voluntary recall for some of its 15-inch MacBook Pro batteries, citing performance concerns with the rechargeable batteries.

Under its free Battery Exchange Program, Apple will replace the batteries for 15-inch MacBook Pro systems sold between February and May 2006. The batteries do not pose a safety hazard, so customers are allowed to use them until their replacements arrive.

"We recently discovered that some 15-inch MacBook Pro batteries supplied to Apple do not meet our high standards for battery performance," Apple said in a statement.

The affected batteries apply to model number A1175 and have a 12-digit serial number ending in U7SA, U7SB or U7SC, according to Apple's advisory.

Apple's voluntary exchange program comes at a time when a number of computer makers have recently undergone mandatory battery recalls, due to the devices overheating and creating a safety hazard. Last year, Apple issued a mandatory recall on some of its PowerBook G4 and iBook G4 systems.