Why does 2019 Macbook Pro battery discharge while on AC when playing games?

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Level 1

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Why does 2019 Macbook Pro battery discharge while on AC when playing games?

When I play graphic-intensive games on my laptop, for instance Diablo III, the battery will eventually discharge to 0% after an hour or so even though the laptop is plugged in. Why does the device use the battery at all when it's plugged in?

I'm running MacOS 12.5.1 and using the Apple-supplied AC adapter. I am not concerned about the battery health. That's not the problem. I'm more concerned why the OS uses the battery at all when connected to AC. In my opinion, the OS should prioritize AC power when plugged in. That, to me, is common sense.

Is there a setting for AC power override that allows direct use of AC power? Based on my internet search, it appears that this has been a long-standing problem with Macbooks.

Please advise.

MacBook Pro 15″, macOS 12.5

Posted on Sep 2, 2022 11:02 AM

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Answer 1

Top-ranking reply

Grant Bennet-Alder

Level 10

133,777 points

Sep 2, 2022 11:26 AM in response to mjstelly

"playing games", while not stressful for you, is one of the most resource-intensive things you can do on your computer.

Your MacBook Pro 2019 computer is a battery-CAPABLE device. It is not optimized as a battery-operated device. (It is NOT an iPhone.)

Your computer performs best when connected to AC power. It can use the full output of the Power Adapter AND when doing especially challenging work will also freely "borrow" power from the battery. In some cases, even with the power adapter connected, the charged state may even decline during stressful work.

When used only on battery, your computer has no extra cushion of power, and will perform more slowly. However, for ordinary non-stressful tasks this may not be objectionable (possibly not even noticeable.)

In general, you should ALWAYS connect AC power when it is possible to do so, and only run on batteries (which will be somewhat slower) when no AC sources are at hand. Your Mac will NEVER over-charge.

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Answer 2

HWTech

Level 9

61,238 points

Sep 2, 2022 1:38 PM in response to mjstelly

Are you using the original Apple OEM charger? And is it the correct charger for your laptop (a problem if you have more than one Apple laptop)? If you use a smaller charger than shipped with the laptop, then you can have this problem because the battery will end up supplying the missing power the smaller charger cannot provide.

Is the charger connected directly to the laptop? Some multi-port adapters, docks, and hubs may not allow the full power of the charger to reach the laptop.

Try connecting the charger to another USB-C port especially on the other side of the laptop. There is a possibility that you may have a problem with one of the USB-C ports which may not allow the full power of the charger to reach the laptop.

Disconnect all external devices since they may be deriving their power from the laptop.

There is one macOS Battery setting which you can try changing which is related to the new Optimized Charging feature:

If battery charging is paused or on hold on your Mac - Apple Support

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Answer 3

mjstelly Author

Level 1

8 points

Sep 2, 2022 11:28 AM in response to Grant Bennet-Alder

I’m not concerned with overcharge. I guess what you’re saying is that the supplied ac adapter is limited in its ability to supply enough power in all case. Of course, I realize that MacBooks aren’t designed as gaming laptops. So it would make sense that it perform like one. Oh well. I had higher expectations.

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Answer 4

mjstelly Author

Level 1

8 points

Sep 2, 2022 2:41 PM in response to HWTech

It is the OEM charger, it's connected directly to an outlet, and the behavior occurs on all the USB-C ports. The battery charges to full and all systems operate normally under all other conditions.

The only odd behavior is that graphic-intensive apps seem to have power requirements that outstrip the AC adapter's ability so the computer makes up the deficit by pulling from the battery. I have a dual-boot system. So I tried the same game on both MacOS and on Windows 10. The behavior is the same on both. So it's not likely an OS issue but hardware.

Does anyone know if this is by design?

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Answer 5

Sep 3, 2022 12:25 AM in response to mjstelly

Yeah... I've also experienced the discharge to Zero (Until Shutdown) while connected to AC Power. Firstly, try switching off "Manage battery longevity" if on also switch off the "Optimised battery charging" Lastly if you change your mind to care about battery health and cycle count... install AIDente I recommend the paid version for seamless use.

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Answer 6

Sep 2, 2022 11:38 AM in response to mjstelly

the 16-in 2019 model was even worse in terms of speed*power product, and that was just about the LAST Intel MacBook Apple produced.

They switched to Apple-Silicon M1 for the next model-year.

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Why does 2019 Macbook Pro battery discharge while on AC when playing games?

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