I am on Xubuntu 12.10. When I close my laptop lid, the screen goes black as normal, and the normal login window appears when I open it up again. However, I notice that for example, I left my laptop closed for no more than about 45 mintues, yet my battery had drained more than 30%. The same thing happened to me the previous night, where I left my laptop lid closed the whole night at around 50, 60%, yet dead by morning. I use xscreensaver. Are there any settings I need to change? I have no background processes running as far as I know.