Therefore I am inclined to believe that a battery of similar capacity is at least possible for my 2008 MBP. Other Unibody MBPs have batteries with capacities up to 8500 mAh while my 2008 MBP has a battery with a mere 5500 mAh. I understand that the 2008 MBP is dated and has components that are more power hungry than newer hardware, but still would like to improve the time between charges. I was just wondering if there was a battery out there that is of a higher density and can last longer.

I had replaced the battery in it with a NewTech replacement from OWC about a year ago. I can only get about 2.5-3 hours of battery life out of the machine. However, the battery life is somewhat subpar on the old MBPs. The main coconutBattery should look similar to the image below, however stats will vary. I am so excited to have my old MBP back up and running. Download and install coconutBattery onto your Mac and upload a picture of the main coconutBattery window here. I was able to have everything on my 2008 MBP replaced with his donor computer giving up its old parts. Mine had blown speakers, weak hinges, a broken clutch cover, and a bad SuperDrive.

I have a Late 2008 MBP (15') that I have basically refurbished because a friend's MBP just like mine had the display go out.

Late 2006 macbook pro battery