MacBook Air M1 A2337 battery/charging issue

[drlarsen]

Hello. Sorry for the long post, but I am trying to decide if this is a simple battery replacement, or potentially something more complicated.

I bought an open box MacBook Air M1 2020 A2337. Seller claimed it was never used. Visually, it appears pristine.

On arrival, the battery was completely flat. Computer powers up and boots fine. Battery status showing 1% and charging, 1 cycle. coconutBattery showing 0 mAh and ~6 watts.
After some hours, the battery status did not improve. Restore via DFU did not help.

I connected the power adapter to a Kill-a-Watt and saw typically 6-7 watts on reboot, however sometimes 20-40 watts for a few seconds on reboot.
I rebooted several times until I saw a steady 24.5 watts while on the boot selection screen, which I hoped meant charging had initiated.

After some more hours, I noticed it had dropped to ~4 watts, so booted into macOS and saw 3%, but not charging. Unplugged power and immediately the screen went black. Plugged in, powered on and back to 1%.

Left it charging overnight and today it shows 100%, but coconutBattery still showing 0 mAh. Unplugging power and immediately the screen goes black. Plugged in, powers on showing 95% - 100%, but coconutBattery always showing 0 mAh and power loss immediately when unplugging.

Reading this forum, I think two things are possible:
1. The battery was flat for too long and needs to be replaced
2. Undisclosed faulty screen replacement could have occurred which causes similar effects

Is there a way I can know it's #1 and not #2 or something worse?

[mon2]

If the display was replaced, you will not have the true tone feature. Check for this. If the true tone is still present, then I would think the issue is a dry battery. Source one from Amazon or Mobile Sentrix for testing.

[drlarsen]

Thank you for the reply. I checked and True Tone is enabled and working. I noticed coconutBattery shows the manufacturing date of the battery and laptop is in 2022, so if it sat on a shelf since then, it is logical the battery is the problem.

[drlarsen]

One further question. Is a defective battery known to limit CPU performance?

I noticed when running Cinebench, the score is much lower than typical 2855 multi-core / 1136 single-core.

Running powermetrics during the multi-core test, I can see the E-cluster at the maximum frequency (2064 MHz), however P-cluster is at a low frequency (828 MHz). Both have 0% idle residency.

I don't think it's a thermal throttle as the core temperatures is only ~40C.
CPU power is only showing ~1900 mW.

[mon2]

Some of the models require a charged battery to operate at the proper speed and to boot. Perhaps this model is one of those. Is there a higher than normal fan spin? If yes, then the fault may be a missing sensor that will cause high fan spin and the cpu speed to be throttled. You can run a diagnostic to confirm if all sensors are accessible.

What are the details of the power adapter? Is it rated to charge this unit? Is it the original OEM model?

Invest into a usb-c power meter (Qianli tail tester at Mobile sentrix - check the videos and is ~$20 Canadian). Use it to monitor the adapter voltage and current draw by the machine.

[drlarsen]

This model is just passive cooling with no fans.

I have the original OEM adapter (I believe) which is 30W. I also have a second Apple 60W adapter, which belongs to my MacBook Pro. Lastly, I have a Dell 65W adapter.
From my understand, the max for this model is 30W, no matter what you use.

I don't have the USB-C power meter, but will look into that as it'd be a useful tool to keep around.
I do have a Kill-a-Watt which measures line voltage/amps/watts, which gives some idea anyway. I never see much beyond 7-8 watts, even at full load on Cinebench.

Thanks again for all the suggestions, I really appreciate the help!