When a battery is charged and discharged, material from the battery plates (active mass) is in motion, through the electromechanical reaction that produces electricity. Every time a battery goes through a charge-discharge cycle, a small amount of this active mass is lost from the plates. Due to so many factors impacting on the life of a battery, it is impossible to stipulate a minimum or maximum life expectancy.

Every battery has a finite number of cycles that it can go through before it loses its active mass, and in turn, its capacity. High usage will often put a battery through this finite number of cycles over a much shorter amount of time, causing a battery to show the above symptoms after only a couple of years. This is not a manufacturing fault.

When a battery is subject to a deep discharge, and/or a rapid rate of recharge, the above process is accelerated. A battery that is deep discharged regularly, will rapidly lose its active mass, and capacity. The loss of active mass, and therefore capacity due to over/excessive cycling is not a manufacturing fault.