Why does my MacBook 12" A1534 say: Battery not installed?
In december 2021 I successfully replaced the battery in my Macbook 12” A1534. I followed the guide Retina MacBook 2015 Battery Replacement by @jeffsu to the letter (including Applying Low Voltage After Every Repair as needed for the Retina MacBook 2015 Only).
For two months it worked perfectly with a fully functioning new battery.
Now without any obvious reason or warning the Macbook cannot find the battery anymore. In “About this Mac > System Information > Power” it just says “Battery Installed: No”.
Here's a snapshot of CoconutBattery.
With the power cord attached the MacBook starts and works normally. There is just no battery indicator at all and without the power cord it shuts off completely.
I've reset PRAM and SMC several times with no change.
I've opened it up and checked the connector from the battery to the logic board. Detached and Reattached it. The same for the usb C connector to the logic board. After applying low voltage again for about an hour (just to be sure) there has been no “power chime” until I've connected the normal power adapter. Then it starts up again normally.
However, still no battery found by the system.
Any suggestions on what I can check out otherwise or do about it?