I leave my battery in my MB all the time, doesn't matter much...

I remember last time (4 monts ago) I watch anime with my MB when I travel from JB to KL, and that day caught in slow traffic, so took me about 5 hours to reach. And in that 5 hours, I was watching anime all the time, until I finish my anime...I still got battery for me to do other stuff like go online with my usb modem for about 1 hour maybe? I set my brightness to 1 bar, using earphone, bluetooth n wireless off.

From my experience, my MB is able to reach 4~5 hours when browsing on wifi and doing some typing. depends on what program u are running.