MacBook Pro discharges partially while sleeping, why?

Question

Hello here,
I noticed that, unlike earlier when I started to use this Mac, if I leave it sleeping in my bag during half of the day only to wake it up later, the battery only holds a charge of anywhere between 75 and 90%.
Of course, the Console doesn't record anything between the time I put it to sleep and the time it is woken up.
How to correct this bug and revert to the standard behavior, i.e. sleeping soundly until needed, without losing more than 1% every 48 hour?

Answer 1

cubytus wrote:
Well, if I am to leave my MBP unused for 2 days, I would leave it plugged in and fully turned on so as to allow for automated backups to be made, especially remote ones (back when SpiderOak worked anyway) as I can't expect a multi-gig upload to complete in a matter of minutes.
Sure, no problem. No harm done in keeping it plugged in and no overcharge will occur. Sugggest you set Energy Saver to turn the display OFF after a reasonable interval, rather than have the screensaver burning the LEDs unnecessarily.
This still doesn't really answer my questionas to why this Mac seems to be burning through the battery when sleeping.
RAM's gotta keep alive, especially if sleeping rather than hibernating. And I suppose faster RAM will need more juice, even if in low power quiesced mode. Back in the days of 667MHz DIMMs would need less than today's 1600MHz SO-DIMMs. Have noted direct correlation with RAM usage: low drain of no apps are running - high drain if everything + kitchen sink is left going prior to sleep.
How can it be compared to the boasted capability of other Macs to retain their charge for up to 30 days while sleeping?
Where would that boast be found? Have read Apple boasting that modern batteries last IN USE throughout a working day (~8-10 hours), but never seen anything about "sleeping beauty" Macs....
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