My Lenovo G50-45 doesn't hold a charge for very long....says it is powered up 100% but only lasts for 30 minutes. Should I be replacing the internal battery or the easily removed bar at the back near where it hinges?
Has nothing to do with the internal CMOS battery. You need to replace the main battery, which is usually what we call a "brick". Generally, it releases from the bottom of the laptop, yes, near the back, and is usually almost as long as the laptop is wide.
I like Anker brand replacement laptop batteries. I've found them to be reliable and last longer than most other aftermarket laptop replacement batteries.