2018 15" MPB Battery Usage/Q's

Discussion in 'MacBook Pro' started by dstama, Dec 3, 2018.

  1. dstama macrumors newbie

    Dec 1, 2018
    Hi everyone

    Have a 1 month old 2018 15" MPB i7 2.6Ghz 512GB model and I feel like my battery is not performing anywhere near it should.

    Before I conclude that it is in fact the battery, I thought I would ask a few questions.

    1. Does the dongle drain power when plugged in? I have been using this for connecting a 2nd 21" HD display and accessing USB devices from time to time. I feel like it simply drains battery by having it plugged in so have no disconnected it when not in use


    2. Does using an external monitor drain battery faster?

    So far, I have only really been browsing the internet and have been getting around 2-3hours max usage with the external monitor. Is that normal?

    I'm now testing the battery drain without the external monitor and no dongle and it does appear to be much better but need more time to ascertain what type of time I'll get out of a full charge.
  2. maflynn Moderator


    Staff Member

    May 3, 2009
    When you use an external monitor, you force the laptop to use the dGPU, which consumes a lot of power, as opposed to the integrated gpu, so its not that surprising you're only getting a few hours worth.

    As for the USB hub, it does draw a little power, my Satechi has a light and there's circuitry, but I would assume the hub itself won't draw much power, but the more items you plug in, will increase the power draw
  3. dstama thread starter macrumors newbie

    Dec 1, 2018
    Thank you. I was hoping it would be the case rather than the battery being a dud given the laptop is only a month old and I have barely installed anything!

    I'll continue to test it out without the monitor and will see how long of a charge I get
  4. dstama thread starter macrumors newbie

    Dec 1, 2018
    Ok, I had it closed/in sleep all night from 11pm to 730pm the next day, and battery dropped from 65% to 58%

    Is that normal for about 20hrs in sleep mode?
    --- Post Merged, Dec 4, 2018 ---
    and now my battery is depleting at a rate of about 10% per 10mins, this is only using Safari
    --- Post Merged, Dec 4, 2018 ---
    What would this beDoes anyone know what this would be?

    This com.apple.WebKit.WebContent seems to be chewing up a lot of battery

    Attached Files:

  5. leman macrumors G3

    Oct 14, 2008
    You probably have a website open that requests a lot of CPU time. Some websites run crypto-miners and other nasty stuff. I’ve also seen ad and tracking scripts take a lot of resources. Rather than looking at energy impact, have a look at CPU. Ideally, your CPU should be under 6-7% if you are not doing anything.
  6. dstama thread starter macrumors newbie

    Dec 1, 2018
    Thanks leman

    I just find it odd that in the first month, I've barely able to get more than 3hours out of a full charge and I've barely being doing anything

    Pretty dissapointing tbh especially considering I get almost a full day charge at work on a 1st gen surface pro, browsing and using spreadsheets etc
  7. Samuelsan2001 macrumors 604

    Oct 24, 2013
    Firstly look at activity monitor and see what is eating your energy. Then what screen brightness are you running on the laptop?? are you gaming or editing 4K video or running 3D simulations, without knowing your use case it’s impossible to tell whether that’s a reasonable battery life or not. Gaming outputting to an external monitor for example will give about 2.5-3 hours.

    I also really cannot understand why you have a dock and a screen plugged in and run it on the battery!! It’s not like it’s portable like that, use it as a desktop in this setup. You should not be running off battery with lots of externals running.

    You can only really test the battery when using it as a laptop try a day using it as it is and see how the battery does.
  8. jerryk macrumors 601

    Nov 3, 2011
    SF Bay Area
    A couple of thoughts. First, some dongles/adapters do drain, especially if they are powering something attached. For example, I create video training classes. As part of this I record voice narrations through an Audio Interface. If I connect this interface (USB A connector) to my laptop through a dongle it drains that battery at 15-20%/hour, regardless of whether or not I am recording.

    To make matters worse, the dongle will even drain at 5% hour if NO USB-A device is connected. I believe this because the thing has LED lights that show the manufacturer's name

    So give that given that you are connecting to USB devices that may be powered via the USB, and an external HD display, which may trigger the GPU to run all the time, I am not surprised you are seeing battery drain.

    If it were me, when I was plugged into these external devices, I would plug the computer into the mains.

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7 December 3, 2018