Apologies if this is a duplicate, but I have searched and not found anyone with the specific problem I'm experiencing.
My MacBook Air (A1466, Mid 2012) has a third party battery that is nearing the end of its life. It has about 250 cycles, but can only power the computer for about 30 minutes.
I have bought 2 second hand official Apple batteries from different eBay sellers. The Air doesn't recognise either of them.
With my current (old but working) third-party battery:
- Plugging in the PSU charges the battery to full capacity
- Capacity drops to about 50% within 30 minutes
- I have to plug in again, or the computer will shut off without warning
With either of the replacement batteries:
- The computer doesn't recognise the battery
- Coconut Battery and System Profiler report no battery present
- Computer shuts off immediately if power cord removed
Things I have tried:
- Resetting PMU
- Resetting NVRAM
- Connecting power cord first, and then the battery terminal second
The last step gets the computer to recognise the replacement battery, but I cannot get it to charge.
- I can read the battery's serial number in Coconut Battery, but it is reported as zero capacity.
- The system battery level menu extra reports the battery as 80% full, but not charging
- Disconnecting the power cord causes the computer to shut off immediately
- The mac cannot be started up from battery alone.
If I replace my old battery, it charges and performs as normal.
This is weird. Surely I can't have bought 2 separate dud batteries? Any advice on how to proceed would be appreciated.