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UPD. It turned out to be quite a lengthy question, so I highlighted the key points in bold. The cycles of my original battery began to exceed 1.3k, the capacity dropped to 67.8%, and the operating system began to report that “Service Recommended.” I decided to replace the battery and searched for a local battery dealer (iFixit won’t ship batteries in my area) and tried to find a brand-name battery of some sort. I found something that the seller claimed was a product from BayEagleEyes Technology Co. for about $97, which I bought. Immediately after replacing it, I charged the battery to 100% and left it plugged in for a couple more hours. After that, I looked at what capacity the battery was showing. Unfortunately, it displayed 5846 mAh instead of the claimed 8775 (just 68%). I decided to calibrate it. To do that, I discharged it before turning off the laptop and left it turned off overnight. In the morning, I plugged it in and fully charged it again. Now the battery was showing even less, 5590 (65%). So, I reset the SMC. Then, I repeated the charge-discharge-recharge cycle. Again it showed even less, now 46 mAh (62%). With each charge-discharge cycle, the displayed battery capacity was dropping.
However, I noticed one oddity - the indicated charge percentage mostly dropped evenly, and then at about 6-7% it froze for about an hour. I wrote to the seller. The seller answered that the only sign of a bad battery could be the battery life. A non-genuine battery in an Apple device will never show the actual charge and percentage, they said. I set up an experiment. Fully charged this new battery, turned on the computer, and loaded the CPU to 100%. The battery lasted almost two hours. Then I put the old, original battery back in. Charged it fully, loaded the processor to 100%. And indeed, the original battery ran out much faster - in about an hour. What to do, who to believe? Should I insist on replacing the battery? Perhaps there is some magic calibration that will make the new battery show the correct numbers?
You should try to return that battery and get this one insteadhttps://eshop.macsales.com/item/NewerTec… I got a battery and ram from them There REALLY GOOOOOOOOOOODDDDD By the way where did you get that battery you got
One thing I will tell you that the battery wasn’t as expected but leaving overnight without any power caused more harm than good which is normal behavior for any batteries. That’s never leave phone, or laptop totally dried up for long time if you care to preserve the battery life. Just saying, try returning your battery and see you can get another one.
