MacBook Air 13" 2015 Suddenly Shuts Down

[Buadhai]

My wife's 2015 MacBook Air has started suddenly shutting down. I replaced the original battery in October 2020 with an Apple battery part. So, the first battery lasted five years and the replacement seems to be dying after less than 18 months.

Or, maybe not.

Oddly, after it shuts down and my wife connects it to power and restarts, the battery indicator is nowhere near 0%. So, it seems to be shutting down long before the battery is depleted.

I've reset the SMC, but that hasn't helped.

What else should I look at?

 

[JPack]

Usually indicates aged or defective cells. Unexpected shutdown can be caused by high internal resistance.

 

[wordsworth]

What happens when the laptop is plugged into a mains socket for any sustained length of time? Does it function okay?

 

[Buadhai]

Usually indicates aged or defective cells. Unexpected shutdown can be caused by high internal resistance.

Thanks. I guess I'll order another battery.

What happens when the laptop is plugged into a mains socket for any sustained length of time? Does it function okay?

Functions fine while on mains power.

 

[StoneJack]

Defective or aging battery. Yes, under some circumstances it may age quickly (depends on usage).

 

[Buadhai]

I’ve ordered a new battery. Thanks to all.

 

[StoneJack]

I’ve ordered a new battery. Thanks to all.

Please tell us about working with new battery

 

[Buadhai]

Sorry for the late reply. The place from which I ordered the battery had to temporarily shut down due to Covid infections of several staff members. I finally got the battery on Friday and installed it on Saturday. I went through the calibration steps recommended by ifixit.

The machine seems to be operating normally now. No more sudden shutdowns. I was able to stream YouTube live over eight hours before the battery got down to around 10%. It will be fine for the sort of work my wife does with it.