Cycle life is the number of times the rechargeable battery can be recharged. Generally, the cycle life of rechargeable batteries varies depending on the appliances in which they are inserted or the way the batteries are used. The cycle life of the rechargeable batteries is defined by IEC directives. This testing is performed within a certain optimal and preset setting for using batteries. The battery will not always be used within these optimal circumstances and in reality this can result in drop of cycle life.