I'm not a battery expert but I think the way it works at the moment is that after fully charging a battery, the laptop will trickle charge the battery. This is so that it alway stays topped up to 100%. Problem is that if you leave the batteries in all the time and never actually use them, then it will gradually screw up your batteries.

Somebody told me to fully charge the battery and then take it out if you're not intending to use it. And every month or so run it down and recharge it.

I've got a couple Dell Li-Ion batteries which in theory should give me about 3 hours together but die after about 1.5 hours.

- Trevor