The life of a battery pack depends on different factors. On the cell type, on how much it is used and on how it is treated. In general, a life of 300-400 charging/discharging cycles can be assumed before the battery?s capacity decreases significantly (80% of the nominal value). This corresponds to a minimum period of use of approximately 2-3 years if the battery is used twice a week. With careful storage when the battery is not in use, a life of 2-3 years is realistic.