Batteries are way more compicated than they first seem.
If the battery is linked to the income AC circuit (which it would be, ofcourse) random voltage spikes could damage battery hold.
Some batterys have bad hold, because they are not properly used. If you plug in your laptop, and once it gets to 80 percent start charging it. You may, depending on battery type, run into charge memory. So that 80percent will basicly mean you could have up to 80 percent less battery life. fortunately its rarely that drastic, only if this was repeated 50 to 100 times may your battery life actually decrease by 80 percent.
My advice, although no problems should occur, just charge it when the battery life reaches <%10 and charge it at 100percent for about an hour. The trickle charge will maintain the battery voltage.
edit: Lol just read nitestick's. Yeh, what he said
