Hmm. I have 15 minute interval logs of battery stats for my mbp since the day I have it logged (with gaps when it was asleep/off) .... about 20,000 entries.

I could extrapolate the data based on my usage patterns (the charging/discharge/etc are all in there)

Anyone know offhand how to tell the charing circuits in the mac to stop charging at 50% capacity? I'm thinking I could easily automate that for a few weeks or months and check out the log data...