I think I may have found the culprit to the battery life. I had noticed this before then must have gotten used to it or forgotten.

I believe the new drive I have in my system, a Seagate Momentus XT is never spinning down. Well, it does spin down briefly ever now and then, but immediately spins right back up again.

I've found a thread over on the Seagate forums of people posting all manner of complaints regarding crashes, slow access and the lack of spinning down. I get great performance and don't notice any pauses that others have mentioned - at least none attributable to the drive. But I do get what a couple of people have mentioned and that's the drastically reduced battery life.

Looks like I may have to retire this thing to an external enclosure for backups.