i find it hard to believe that whatever youre doing (to drain down the battery while plugged in) would be continuous for a solid 5 hours. Honestly whenever i ramp up my computer to the max its usually for a few minutes, maybe like an hour at the most. But to max your computer out for 5 or 6 hours (however long it would take to drain the battery completely while charging) doesn't seem plausible. In all honestly, sounds like you should have bought a higher spec'd computer.
Im still saying that you'll be able to infinitely work on your computer because as mentioned above i doubt you'll ever stress your computer long enough to drain the batter while plugged in
No he would never drain the battery. Take this guys comments with a grain of salt, he is probably looking for a way to return another computer. He has returned about 10 already with ridiculous claims like the hard drive skipped when he was playing music loudly.