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User profile for user: zeromancer1972
zeromancer1972 Author
User level: Level 1
8 points

MBP 16" 2019 on power adapter but battery drains constantly

I experience this behaviour for some weeks now: my MBP 16" is running with the power adapter (100W) but it seems that this is not enough to run this machine since the battery is drained constantly.

I use the stats tool to monitor the power consumption and it's below the 100W the charger should supply. It seems it's not able to deliver it, because the battery level is constantly decreasing. The minimum I saw was 5%.

This evening I started with 100% battery and even still being connected to the charger, the battery level is now at 34%. I am pretty sure that using power from the battery even when using the charging brick couldn't be ideal for the battery.

What is this? A software bug or does the charger not deliver enough power?

I have a smart socket with power measurement between the mains and the power adapter and this doesn't go above 65W, so the Macbook should be powered properly.

I wouldn't bother but when the battery is reaching a level of 10% or lower, I also experience throttling of the CPU/GPU - and I am viewing some YT videos here currently.

Anyone else seeing this?


Posted on Oct 30, 2022 3:39 PM

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User profile for user: HWTech
HWTech
User level: Level 9
60,380 points

Posted on Oct 30, 2022 5:57 PM

Are you connecting the charging cable directly to the laptop? If so, try using another USB-C port especially on the other side of the laptop in case a USB-C port or I/O Board is bad. An adapter (especially the Apple mult-port adapter) may not allow the full power of the charger to reach the laptop.


Disconnect all other external devices in case one of them is causing a problem.


Try an SMC Reset. Make sure to read the instructions carefully since the procedure is different for the 2018+ T2 models than it is for the older Macs. It also never hurts to try a PRAM Reset (hold the PRAM reset for two chimes).


Unplug the charger from the electrical outlet for a few minutes in order to reset the charger's internal circuitry.


Try running the Apple Diagnostics to see if any hardware issues are detected. A passing diagnostic does not necessarily mean everything is Ok.


See this Apple article for troubleshooting USB-C charging issues:

If your USB-C power adapter isn't charging your Mac notebook - Apple Support


Do you have the same issue while booted into Safe Mode which prevents third party apps from automatically launching during boot & login? If Safe Mode is Ok, then it means you have some third party software installed which is affecting the normal operation of macOS. Typical culprits are anti-virus apps, cleaning apps, and third party security software....none of which are needed on a Mac. You can run EtreCheck and post the report here using the "Additional Text" icon which looks like a piece of paper if you want the forum contributors to look for any possible software issues and interpret the report for you.


Another consideration is how the new Battery Management system works beginning with an update in macOS 10.15 Catalina. By default macOS will let the battery charge drain in order to exercise the battery and leave the battery at an 80% charge level at times even if the laptop is always plugged into the charger. See this Apple article for details on the new Battery Management feature:

About battery health management in Mac notebooks - Apple Support


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User profile for user: HWTech
HWTech
User level: Level 9
60,380 points

Oct 30, 2022 5:57 PM in response to zeromancer1972

Are you connecting the charging cable directly to the laptop? If so, try using another USB-C port especially on the other side of the laptop in case a USB-C port or I/O Board is bad. An adapter (especially the Apple mult-port adapter) may not allow the full power of the charger to reach the laptop.


Disconnect all other external devices in case one of them is causing a problem.


Try an SMC Reset. Make sure to read the instructions carefully since the procedure is different for the 2018+ T2 models than it is for the older Macs. It also never hurts to try a PRAM Reset (hold the PRAM reset for two chimes).


Unplug the charger from the electrical outlet for a few minutes in order to reset the charger's internal circuitry.


Try running the Apple Diagnostics to see if any hardware issues are detected. A passing diagnostic does not necessarily mean everything is Ok.


See this Apple article for troubleshooting USB-C charging issues:

If your USB-C power adapter isn't charging your Mac notebook - Apple Support


Do you have the same issue while booted into Safe Mode which prevents third party apps from automatically launching during boot & login? If Safe Mode is Ok, then it means you have some third party software installed which is affecting the normal operation of macOS. Typical culprits are anti-virus apps, cleaning apps, and third party security software....none of which are needed on a Mac. You can run EtreCheck and post the report here using the "Additional Text" icon which looks like a piece of paper if you want the forum contributors to look for any possible software issues and interpret the report for you.


Another consideration is how the new Battery Management system works beginning with an update in macOS 10.15 Catalina. By default macOS will let the battery charge drain in order to exercise the battery and leave the battery at an 80% charge level at times even if the laptop is always plugged into the charger. See this Apple article for details on the new Battery Management feature:

About battery health management in Mac notebooks - Apple Support


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MBP 16" 2019 on power adapter but battery drains constantly

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