I installed a SSD in my hard drive area and a 2nd HDD in the optical bay with using one of the many kits you can buy to do this. I am enjoying having a 2nd drive, but the battery life is pretty bad. I think I'm getting less than or around 3 hours of battery. I have 2011 MBP and can't believe the 2nd drive is causing the battery to take such a hit. Is this common with dual drives? I'm also wondering if the battery life depends on what kind of programs your running and how many. It seems like it can get better battery life if I don't do a whole lot on my MBP, something like just browse the internet with one window. Anyone know what can be done to help extend the battery life?