2017 MacBook suddenly charging very slowly

[camner]

I have a 2017 12" MacBook which has been serving me very well until recently.

It typically charged from nearly empty to 100% within 2-3 hours.

Starting a few days ago, when I plug in the USB-C charging cable, the icon will show a battery with a superimposed plug, and when I click on the icon, it says "Battery not charging." But it IS charging, only very, very slowly; it can take almost an entire day to get back to 100%.

I've tried a different USB-C cable and a different charger, but the behavior remains the same.

Any ideas about what could be going on here?

Here's a screenshot of the output from coconutBattery, which seems to show that the battery is in good shape (albeit with only 82% of original charge capacity)

 

[StoneJack]

smc and pram reset

 

[camner]

smc and pram reset

Thanks for tip. Unfortunately, that didn't work.

What I did notice that I hadn't before is that when I plug in the power cable, I get the typical sound that indicates charging. But, the battery icon changes to a superimposed plug, and when I click on the battery icon in the menu bar, the drop down says it is not charging, though it obviously is (just very slowly).

 

[StoneJack]

Thanks for tip. Unfortunately, that didn't work.

What I did notice that I hadn't before is that when I plug in the power cable, I get the typical sound that indicates charging. But, the battery icon changes to a superimposed plug, and when I click on the battery icon in the menu bar, the drop down says it is not charging, though it obviously is (just very slowly).

repeat smc reset

 

[StoneJack]

Thanks for tip. Unfortunately, that didn't work.

What I did notice that I hadn't before is that when I plug in the power cable, I get the typical sound that indicates charging. But, the battery icon changes to a superimposed plug, and when I click on the battery icon in the menu bar, the drop down says it is not charging, though it obviously is (just very slowly).

repeat smc, reformat and reinstall, use Apple charger, reboot

 

[arcite]

No need to reformat or reinstall…. The battery is aging and dying. A new battery would be about $150…. That would fix ya up.

smc reset may help….but at the end of the day, your battery is from 2017….it’s old.

 

[camner]

Thanks @arcite I ended up taking the laptop into the local Genius Bar, and that’s pretty much what they told me. They said the battery was marginal and that it was time either to replace the battery if I wanted to get more life out of the laptop or consider a new machine (I’m sure Apple would prefer me to do the second!)

 

[Ruggy]

They are being honest 82% is marginal.
Liion batteries tend to work brilliantly right up to the end but when they die it's sudden and like falling off a cliff.
Our 2016 Macbook is getting to the same. Has been brilliant and nothing of the same size and weight to replace it so it may well be worth fixing for you if it does all you want.

 

[EugW]

Thanks @arcite I ended up taking the laptop into the local Genius Bar, and that’s pretty much what they told me. They said the battery was marginal and that it was time either to replace the battery if I wanted to get more life out of the laptop or consider a new machine (I’m sure Apple would prefer me to do the second!)

Did they say they would fix it under the battery warranty program? I had thought they need it to be under 80% to qualify for that program.

 

[camner]

Apple did NOT say that they would fix it under the battery warranty program. Since it is a 5 year-old computer, I'm not surprised.

 

[EugW]

Apple did NOT say that they would fix it under the battery warranty program. Since it is a 5 year-old computer, I'm not surprised.

I misspoke. Does it qualify for the $200 battery replacement? I thought it had to be under 80% capacity. Otherwise it doesn't qualify. 5 years old doesn't matter.

 

[camner]

I've done some more poking around with my laptop, I have FINALLY discovered a consistent circumstance when the laptop stops charging. It has to do with CPU usage! When CPU usage (as reported by Activity Monitor) rises above about 25%-30%, the charging icon changes to a plug icon. Then, when CPU usage drops below 20% or so, it goes back to charging.

This is definitely behavior for me. According to the Genius at the Apple Store (who tested and found nothing wrong), my battery is "marginal" because it is at about 82% of capacity. Could a new battery fix this issue by itself, or is it likely that something else is wrong?

 

[camner]

I misspoke. Does it qualify for the $200 battery replacement? I thought it had to be under 80% capacity. Otherwise it doesn't qualify. 5 years old doesn't matter.

Well, the guy at the Apple Store quoted me $200. Of course, he could have been mistaken.

 

[camner]

I've done some more poking around with my laptop, I have FINALLY discovered a consistent circumstance when the laptop stops charging. It has to do with CPU usage! When CPU usage (as reported by Activity Monitor) rises above about 25%-30%, the charging icon changes to a plug icon. Then, when CPU usage drops below 20% or so, it goes back to charging.

This is definitely behavior for me. According to the Genius at the Apple Store (who tested and found nothing wrong), my battery is "marginal" because it is at about 82% of capacity. Could a new battery fix this issue by itself, or is it likely that something else is wrong?

(Sorry for the double post...that was unintentional, and I can't figure out how to delete a post)

 

[EugW]

Well, the guy at the Apple Store quoted me $200. Of course, he could have been mistaken.

If 82%, that’s pretty close to 80%. I believe they have some discretion to offer you those repair prices if it’s close to their guidelines. Or maybe the weird charging behaviour made the difference. For $200 I personally might have taken the deal given what’s involved.

 

[camner]

If 82%, that’s pretty close to 80%. I believe they have some discretion to offer you those repair prices if it’s close to their guidelines. Or maybe the weird charging behaviour made the difference. For $200 I personally might have taken the deal given what’s involved.

I'm certainly tempted...my only concern is that my charging issue may or may not be fixed by replacing the battery. If something more serious is amiss, I don't want to spend $200 on a battery and still have the charging issue.

 

[camner]

Finally figured out what was causing the charging issue. I was using an Anker 2-port 40 watt charger, and in addition to the USB-C to USB-C cable for the Macbook I had a USB-C to Lightning cable plugged in for my iPhone. What I didn't know is that although the Anker charger can give the full 40 watts to one cable if there is another cable plugged into the charger that isn't attached to a load, Lightning cables are special cases! When a Lightning cable is attached to a charger and not to an iDevice, the charger thinks there is a load anyway and splits the 40 capacity 50/50 to the two cables. (Info courtesy of Anker support.) So, the MacBook was only getting 20watts (verified by looking at the System Report in About this Mac). As soon as I unplugged the Lightning cable, the full 40 watts was allocated to the MacBook and my issue disappeared.