Apple is launching a battery replacement program for select iPhone 5 units.

In a statement posted at the company's website, Apple said that it had found out about a very small percentage of iPhone 5 units that have their batteries suddenly having a shorter life or requiring to be charged more often.

Apple said that the affected units that are eligible for the battery replacement program have serial numbers that fall within a limited range and were sold between September 2012 and January 2013.

Users that possess the affected iPhone 5 units, experiencing the bad battery symptoms and meeting eligibility requirements, can have their iPhone 5 battery replaced for free. The replacement program does not include the iPhone 5C or the iPhone 5S.

Users can choose to have their iPhone 5 battery replaced by either taking their iPhone 5 unit to an Apple Authorized Service Provider, setting an appointment with an Apple Retail Store, or by contacting Apple Technical Support. 

However, if their iPhone 5 unit has any damages that will prevent the proper replacement of the battery, such as a cracked screen, the user will have to shoulder the expenses of having the damages fixed before getting their free battery replacement.

Before users undergo the process for battery replacement, Apple encourages them to back up the data of their iPhone 5 using iCloud or iTunes, turn off the Find my iPhone feature, and then erasing the phone's content and settings.

The replacement batteries are available in the United States and China since August 22. For other countries, the replacement batteries will be made available a week later on August 29.

Apple may also choose to only replace batteries of affected iPhone 5 units only within the country where the unit was originally purchased.

Users that have defective batteries for their iPhone 5 units that have already paid for a battery replacement can also contact Apple about receiving a refund for their expenses.

Apple also adds that the battery replacement program does not extend the warranty period for iPhone 5 units, and lasts for two years after the retail sale of the unit or until March 1 of next year, whichever of the two dates provides the longer period of coverage.

In addition to this battery replacement program, Apple also currently has in place a replacement program for faulty sleep/wake buttons of a small percentage of iPhone 5 units.

The standard replacement procedures also apply for the on/off button replacement program for iPhone 5 units.