hey guys, sorry if this has been discussed to death already but i have some burning questions re: battery care 1. if the battery is fully charged and you leave it plugged in, won't that be overcharging the battery and won't it decrease the battery's longevity? or does the power cut automatically when it's fully charged? 2. if you charge the battery only halfway and have to stop charging because you need to bring the laptop away from the power source, does that affect the battery longevity also? 3. i heard that lithium batteries should never be completely discharged. so is it advisable to start charging when your power falls to 20% and not let it completely discharge except to callibrate it every month?