Battery Timer?

Having just replaced the battery on my MBP (only 74 cycles) I am curious if anyone knows of a battery timer utility.

I'd like a semi-automatic way of keeping track of how long my battery lasts between charges. No, I don't want to keep track by pencil and paper. The logic would be a bit complicated, but it would be great if iStat, for example, could keep track of how long the battery lasted between chargings.

 

Yup, it would be interesting to see how much sleep time was used as well. Something like:

Last recharge: 1/31/2007
Active time: 2 hrs, 16 min
Sleep time: 4 hrs, 21 min
Remaining charge: 29%

An while were at it a little DB of past cycles would be nice, too.