A charging cycle refers to the process of charging a battery from a low state of charge to a full state and then discharging it back to a low state. This cycle is crucial for understanding how batteries, such as those in smartphones or electric vehicles, perform over time. Each complete cycle can affect the battery's overall lifespan and efficiency. Batteries typically have a limited number of charging cycles before their capacity diminishes significantly. For instance, a lithium-ion battery may last for about 300 to 500 full charging cycles. Proper management of charging cycles can help extend the life of devices and reduce the need for replacements.