When laptop users leave their laptop battery inside the machine but leave the computer plugged into the wall, the laptop battery is going through a constant charge-discharge cycle. The notebook battery is sitting unused inside the notebook, discharging a little faster than normal because of the notebook’s heat. Once its charge level drops to a predetermined level (which is different for each manufacturer), the AC adapter provides extra juice to “top off” the notebook battery. As the laptop battery gets older, it tends to self-discharge a little faster, which accelerates the process even further.
Lithium ion notebook batteries normally offer 600 to 800 charge/discharge cycles over 1 to 3 years of useful life. When you use your notebook battery as described above, you are needlessly using your supply of recharges.
One additional note: many people recall that older notebook batteries on early computers worked best when they were fully discharged before being recharged. While that remains true for Nickel Cadmium technology, today’s Lithium Ion notebook batteries work best when they are recharged when they still have 10 to 20% capacity remaining. So if you are using your notebook battery on a long flight, try not to get in the habit of using the notebook battery until it has almost no charge. Your laptop battery literally won’t be the same when you re-charge it the next time.
Notebook/Laptop Battery Shelf Life
