I just ran my battery down to calibrate, except that about 1/4 through the process at about 60% I turned on caffeine & had it run down to 3% & got the battery reserves warning. It is now just shut off. If one does a calibration without using the sleep mode, after the low battery warning, does one just shut their mac down when it gets to about 2-3%? & does one have to wait 5 hours before plugging it back in to charge? the whole process could be a little awkward as I cant be around the mac the whole time to monitor the calibration process, so I most likely will do this overnight, but the trouble with this is I may sleep through the low battery warning or miss it & it goes down lower than 2%. Should I just let it go to rock bottom or would it be harmful if it goes until the mac just shuts off?