<p>Hawkwings hit the nail on the head, Lithium Ion battery’s must be run dead every once in awhile or they start to deteriorate, I bet if you read through the documentation somewhere it will say this. I know Apple recommends one full run down and charge up per month of the lithium ion battery in its iphone and ipod touch. </p>
<p>Here is one better, straight from apple. </p>
<p>[Apple</a> - Batteries - Notebooks](<a href=“http://www.apple.com/batteries/notebooks.html]Apple”>Batteries - Maximizing Performance - Apple)</p>