New Battery Is Not Being Recognized By My Mbp Macbook Pro 13 Unibody Mid 2012

Chosen Solution

Is the battery an OEM battery? If It’s not then that is the problem, many aftermarket batteries for MacBooks are not proper and could actually cause the board to short. Try a NVRAM reset as well. NVRAM Reset Guide

What happens when you put your old battery back in? If it still responds in the same way I’m suspecting the SMC logic on the logic board has a problem.