Apple revealed on Friday that it will be replacing batteries in a small percentage of iPhone 5 devices that have suddenly experienced shorter battery life or required frequent charging. The affected phones were sold between September 2012 and January 2013 and can be identified via a limited serial number range.

Apple will replace batteries in eligible devices free of charge. For those that are qualified for the replacement and have already paid to replace their iPhone battery Apple will provide a full refund. However, if iPhones have damage that impairs the replacement of the battery there may be a cost associated with the repair.