Wacky battery report -- ghost using my computer at night?

Why does my laptop's Battery Report sometimes say that it was Active when I know I wasn't using the computer and had the lid closed, and sometimes says Suspended when I was using it? Sometimes it says it was active for hours on end in the middle of the night, when I know I was asleep! Very weird. I thought Active means that the lid is open and the computer is in use, and Suspended means it is closed. Am I wrong on that?

Question by Glaucoides on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.