iFixIt batteries do not work if you are running OS 10.11.2. Tried 2 iFixIt batteries and received guidance from iFixIt customer support.... Same result, it didn't work. Just spend a few dollars more and take it to an Apple Store.
If you are running OS X 10.11.2 or newer, battery provided by iFixIt will not work. I've already tried 2 batteries from iFixIt and neither worked. iFixIt needs to come clean on this unfortunate situation. I've already put 8 hours into this futile effort when it should have taken me 45 minutes.
I think you are SOL. I had same problem a few days ago. I have attempted everything I could find from online resources. Bottom Line: ship it to an Apple authorized repair shop or an Apple Store. Battery replacement Cost is now only $130, which isn't much more than iFixIt cost.