The question found here is similar to mine:
Some users alluded to the answer to my question. However, I am specifically asking if any battery energy at all is used while my Canon 5D Mark ii is off and the battery is still in it. I'm talking about leaving the battery in the camera for (eg) 2 weeks.
In other words, will the battery have any more juice (even a small amount), if it is stored outside of the camera?