The predicted life cycle of Lithium-Ion batteries is now 1,000 charge cycles, the point at which the charge capacity of the battery declines to 80% of the as-built capacity. A few years ago the predicted life cycle was 300-500 charge cycles. So there has been great improvement in Lithium-Ion technology.
But keep in mind that there is no guarantee that a particular battery will achieve that predicted life cycle. The prediction is nothing more than that peak of the normal distribution, i.e., bell-curve, of the total population of Lithium-Ion batteries. The statistical distribution means that there will be batteries that fail earlier than the peak, as well as batteries that fail much later than the peak. The vast majority will make it to the peak before capacity drops to 80% of the as-built capacity.
In addition to normal distribution of life cycles, the environmental exposure and use pattern will significantly affect the cycle life of the battery. Lithium-Ion technology is VERY sensitive to temperatures, that is why the portable devices all have a usable temperature range, and recommendations on storage temperature. Heat and cold adversely affect the life of the battery.
Discharge/charge behavior have an impact on battery life cycle...deep discharge/charge are very detrimental. And contraty to published information, that does not calibrate the battery. It merely calibrates the charge reporting circuitry. Discharge to 50% and then charge has been shown in tests to result in four to five times the battery cycle life of discharge to shutdown and charge.
So keep your battery in the proper temperature range, and only discharge to 50% before recharging if you want longer battery life.
