I'm the manager of local repair shop in Reno, Nevada. I haven't been working for very long, but I've learned a lot in the time I have. I've been interested in computers since I was 16, and I'm lucky enough to work on them every single day. Although I'll never call myself an expert, I do my best to troubleshoot and I haven't run into anything yet that I had to give up on! Also a major Star Wars geek...
How do I flag as duplicate?These two posts are one in the same, and he answered his own question: https://www.ifixit.com/Answers/View/5434......
Answer to "Battery not recognized after replacing "damaged" battery"According to the [guide|27316|iFixit guide], you need to calibrate your battery before using it by allowing it to drain overnight, then charging it to 100% and draining it again until your MacBook Pro shuts down automatically. Then you can charge it again and use it normally, However since it’s not being recognized at all, you should reset your MacBook Pro’s SMC (Also found on the iFixit Guide). You can learn how to do this here: https://support.apple.com/en-gb/HT201295 Good luck!