The good ol' days, wow 11K-13K mAh in an Apple laptop. Crazy. I believe the latest 15'' touch bar MBP's have only around 6.6K mAh.
Your 2-3 hours could be because of the age, it's a laptop from 2009 after all.
My 13'' nTB MBP has only 4.5K mAh and lasts about 4h on battery with twitter, YouTube, web, music.