I recently calibrated my battery on my mbp late 2008 and according to coconut the capacity is at 86% and has 90 load cycles. it now says 2 1/2 hour capacity shouldn't i be getting longer than that?
The time remaining is an ever-changing estimate, based on the current workload on your system. Battery life from a charge is affected by many factors. This should answer most, if not all, of your battery questions: