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external monitor and power usage.

When connected to an external monitor (samsung 27'), my macbook pro 13' battery drains quicker even though it does not supply power to the monitor. They are connected through a usb c to hdmi port. Any tips to help curb the energy drain from the macbook? Cheers.

Posted on Jun 14, 2021 8:34 PM

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Question marked as Top-ranking reply

Posted on Jun 15, 2021 5:44 AM

I would try few simple resets.


Go step by step and test.


1. Reset PRAM:  Reset NVRAM or PRAM on your Mac - Apple Support

     Settings that can be stored in NVRAM include sound volume, display resolution, startup-disk selection, time zone, 

     and recent kernel panic information. 

     The settings stored in NVRAM  depend on your Mac and the devices that you're using with your Mac.


2. Reset  SMC:   How to reset the SMC of your Mac - Apple Support   Choose the appropriate method.

    Quote:

    Resetting the system management controller (SMC) can resolve certain issues related to power, battery, fans,

    and other features.



3. Startup in Safe mode. https://support.apple.com/en-gb/HT201262

    To leave Safe Mode, choose “Restart” at the bottom.

    Quote:

     Safe mode prevents your Mac from loading certain software when it starts up, including login items, 

     system extensions not required by macOS,

     and fonts not installed by macOS. It  also does a basic check of your startup disk, 

     similar to using First Aid in Disk Utility

     And it deletes some system caches, including font caches and the kernel cache, 

     which will be created again automatically as needed.



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8 replies
Question marked as Top-ranking reply

Jun 15, 2021 5:44 AM in response to windows_user_convert

I would try few simple resets.


Go step by step and test.


1. Reset PRAM:  Reset NVRAM or PRAM on your Mac - Apple Support

     Settings that can be stored in NVRAM include sound volume, display resolution, startup-disk selection, time zone, 

     and recent kernel panic information. 

     The settings stored in NVRAM  depend on your Mac and the devices that you're using with your Mac.


2. Reset  SMC:   How to reset the SMC of your Mac - Apple Support   Choose the appropriate method.

    Quote:

    Resetting the system management controller (SMC) can resolve certain issues related to power, battery, fans,

    and other features.



3. Startup in Safe mode. https://support.apple.com/en-gb/HT201262

    To leave Safe Mode, choose “Restart” at the bottom.

    Quote:

     Safe mode prevents your Mac from loading certain software when it starts up, including login items, 

     system extensions not required by macOS,

     and fonts not installed by macOS. It  also does a basic check of your startup disk, 

     similar to using First Aid in Disk Utility

     And it deletes some system caches, including font caches and the kernel cache, 

     which will be created again automatically as needed.



Jun 15, 2021 7:39 AM in response to windows_user_convert

Your MacBook Pro is battery-capable device, not a battery operated device like an Apple Watch or an iPhone.


If you connect desktop-calibre devices to it, it will use MUCH more power to talk to them, and drain its battery MUCH more quickly.


The simplest solution is to plug in your power adapter when you plug in the (wall powered) display.

Jun 18, 2021 6:54 AM in response to Paul Baughman

Your MacBook Pro computer is not optimized to be run on battery at all times, like an iPhone or Apple Watch.


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. There are three micro-controllers cooperating on battery and charging issues, and your Mac will NEVER over-charge.



Jun 18, 2021 7:00 AM in response to Paul Baughman

It means it is capable of running on battery, but does not do so exclusively. A battery-operated device exclusively runs on battery. Your computer uses the battery when not plugged in; it does not use the battery when plugged in. To reduce the rate of accumulation of battery cycles leave the computer plugged in. When not convenient to plug in the computer, use it on battery power, but expect the battery to drain when doing so.

Jun 18, 2021 8:00 AM in response to BobTheFisherman


When my iphone is plugged in, it charges the battery while running the functions.

When the MBP is plugged in, it charges the battery while running the functions.

When either is not plugged in, it runs from the battery, thus draining the battery.


I'm not a hardware designer/engineer, but this sounds like a Spock-ism. "A difference that makes no difference *is* no difference."

Jun 18, 2021 9:23 AM in response to Paul Baughman

When on battery power alone, your computer has no extra cushion of power, and will perform more slowly.


When you connect desktop-calibre accessories and devices, the battery may drain shockingly fast, and this is NOT seen as a deficiency. It is a feature of a battery-capable device, not intended to run all day every day on battery under any and all conditions.


Your initial query was about external monitor use. Your computer will NOT be able to run all day on battery alone with an external monitor connected. The interface to an external monitor uses more power than can be conveniently supplied from the battery alone. (Unless you plug in the computer when you plug in the external monitor.)

Jun 18, 2021 9:25 AM in response to Paul Baughman

Paul Baughman wrote:


When my iphone is plugged in, it charges the battery while running the functions.
When the MBP is plugged in, it charges the battery while running the functions.
When either is not plugged in, it runs from the battery, thus draining the battery.

I'm not a hardware designer/engineer, but this sounds like a Spock-ism. "A difference that makes no difference *is* no difference."

OK.

external monitor and power usage.

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