Right after the normal "battery priming" I noticed this, but never bothered to ask or do anything about it. I use my late 2008 uni mbp mostly as a desktop replacement (external monitor/kb, etc.) and it is plugged into the outlet 98% of the time. I have noticed that when it is fully charged (100%) and I put it to sleep overnight, the next morning the battery shows (99%)...another day passes and it gets to (98%), another day and (97% and so on) till I unplug it and use it as a portable and let the battery get low before I plug it back again... The battery shows 100% health all the time and whatever the charge is left for the day.... Is this normal for this batteries to loose a bit of charge every day when plugged in? Is it a defective battery? I'd like to hear from people that use their MBP in clamshell mode most of the time before calling apple care.. thanks!!!