Chosen Solution
Ok, I got ifixit Macbook Pro 15” Retina Mid 2012 battery replacement kit. I successfully replaced it and when I turned on the Mac it was 50% charged with 8460 mAh. Right after 1 charge cycle, It just dropped to 7800. what is the reason for that? Should I drain the battery and recharge several times or is it the defective battery? Can you help me about it? Update (12/29/2018)
this the info about battery
Ok I’ve done SMC reset it’s all good for now.
