Chosen Solution
I installed my ordered ifixit battery yesterday, but upon checking the health I came across the age of the battery which 10.2 years old with a manufacture date of 3 Jan 2011 using battery health 2 app which I don’t think reliable. I am following the instruction to calibrate, but while discharging from 100% to 0% the battery went from 40% to 7%. This has me worried. Ifixit have said to run the battery for 20 cycles to properly calibrate. Update (03/03/2021) its been a few weeks now. I was sent a replacement battery the old battery was at 67% health at the end with 55 cycles on it. I installed the replacement yesterday, I am sorry to the same thing is happening. The battery is calibrated. I am charging it to 100% then when discharging the power levels drop from over 50% to 7%. I think they need to change their supplier. Update (03/03/2021) the replacement battery is now has 5 cycles and the battery health is down 10%. I have followed the calibration instructions as before. I am using better battery 2 app to see the status of the battery and usage history details.
It sounds weird that it says that the battery is so old. I would recommend you to contact the iFixit support about that and they will help you, here is a link to the support contact information. iFixit Support
looks like I have same problem with my MacBook Pro 15 mid2014. bought on eBay one month ago with 4 cycle count battery, now has 40 after one month usage and battery health dropped from 9000 mah to 8300. i’m using 100% original MagSafe 2 charger directly from apple.com so maybe seller sold me refurbished MacBook with bad battery quality. I’m losing 200mah every week with only browsing use ?
