Charge cycle

Using and recharging 100% of battery capacity equals one full charge cycle. A charge cycle means using all of the battery power, but that does not necessarily mean a single charge. For instance, you could listen to your Apple iPod for a few hours one day, using half its power, and then recharge it fully. If you did the same thing the next day, it would count as one charge cycle, not two, so you may take several days to complete a cycle.
Each time you complete a charge cycle, it diminishes battery capacity slightly, but you can put both Apple iPod batteries through many charge cycles before they only hold 80% of original battery capacity. As with other rechargeable Apple batteries, you may eventually need to replace your battery.