Upgrading to MacOS 10.7 (Lion)? My battery lasted about half as long as it used to once I upgraded. I went to Utilities -> Console and had a huge list of messages in the system query log. I found that Little Snitch wasn’t compatible with Lion and kept “respawning” every 10 seconds. Then I found that Adobe Air was being denied access to a file it wanted to read. I removed Little Snitch and Adobe Air and my battery life is again excellent. Watch out for incompatible programs!