Hhaha.. 12? Try 6.. LOL.  Batteries get abused.. all the time, even if when you are "powered" you aren't really powered, you are still running off of battery power.. the battery is being "charged" constantly by external power.. That's the reason why you can pull the external cord from a laptop and still be running.. the battery is ALWAYS the primary source..

Not to Dis, but if the battery is primary, how is it that a system can be powered on & run without the battery?  I don't disagree with your statement, but I think the power circuitry is a bit more sophisticated.

Battery life expectancy & cost is my primary reason for not personally owning a notebook computer.