All batteries have a life span, even if left in the box and never used. Time is a factor even if properly cared for, eventually, all batteries die. An EarthX battery is rated for up to 6 years if properly maintained, which means it is not left in a discharged state (below 13.28V); used in a properly functioning charging system; used with a proper charger; not shorted; and proper temperature ratings have been followed. All batteries will self discharge and depending on the amp hour of the battery, and it’s temperature it is stored in, the level of discharge and amount of time are variable. Always keep your lithium battery above 13.28V for longest life.