While using battery power, and leaving the clamshell open on my mid 2010 MBP, it appears to "sleep" in 3 minutes or so, which is my pref setting while "Battery" mode. But, when I return, like 6-8 hours later, the battery has run flat, and when it went to "sleep", it was between 70-80%. If I remember to close the clamshell lid, the battery drain is much less severe after 6-8 hours, maybe down an additional 10% Several questions for those with more experience than I; - are there a user settings other than "Energy Saver" pref that I am overlooking, to enable a lower power "Sleep" mode? - Does Time Machine continue to run in "Sleep" mode, and yes I do have it set to backup while on battery power? - Is the Sleep mode different with the lid open versus closed? If so, any idea why? - Will routinely resetting SMC, PRAM, and NVRAM improve this situation? - Is their 3rd party s/w that I should consider? All input is appreciated.