Macbook Aluminum Sleep Mode Problem

[TbmnL]

Prior to this Macbook, I had been using a 3 year old iBook which I rarely turned off and was always on sleep mode whenever it was not in use. I know the battery percentage drops a little, but last night before closing the lid, my Macbook's battery was at 78% and when I woke up this morning the battery drastically dropped to 13%. I have never seen that big of a dropped on my iBook. I've had this laptop for two weeks and this is the second time it's happened. Anyone have this problem? Is there anything I can do or should I just bring this to the Genius Bar? Thanks in advance!

[chill.]

i've had something similar happen (but only once so far). i put the laptop to sleep in the morning, then placed it in my backpack. when i took it out about 2-3 hours later, the battery had gone down to 60% and my macbook was very hot.

i suspect that my macbook woke up while it was in my backpack, or the sleep isn't a very deep sleep and is sucking up a lot of battery. in other cases though, i've had my macbook sleep fine without using up that much battery life