Auto-brightness a bit screwy

Discussion in 'MacBook Pro' started by ascender, May 19, 2017.

  1. ascender macrumors 68020

    Dec 8, 2005
    Not sure what other word to use and I can't see anything with the search facility, but on a 13" TB, I'm sitting in a room with no artificial light and no bright light streaming in or anything like that. Every 10 mins or so the laptop seems to auto-dim the display to a near-unreadably dark level.

    It then seems to settle down and be fine for a while before occasionally turning up to 100% (draining battery).

    Has anyone seen this behaviour before? Is it a macOS feature/bug or maybe a faulty sensor? It doesn't happen all the time which is strange, but the lighting conditions aren't changing which makes me think its maybe a fault.
  2. bcbickers macrumors member


    Jan 13, 2011
    Katy, TX
    I have noticed this same behavior, and it seems to be related to the colors being displayed on the screen. If I maximize a Skype session, which has a black background, the screen dims. Switch to Safari, and it brightens up. Very annoying. And it has a big impact on battery life. I have since disabled auto brightness and use the brightness slider on the touch bar to manually adjust. This has taken battery life from roughly four hours with auto brightness on to over six with manual brightness around 50%. My usage pattern has been the same since I got the machine. For instance, I have been powered up and on battery (13" tb model) since 6:45 am this morning. It is now 10:15 am, and I am at 56%. In those 3 1/2 hours, I have been on three Skype calls (2 1/2 hours or so), in and out of Outlook, Word, and PowerPoint, digging through tech articles on various websites using Safari, and running Visio in a Windows VM (Fusion). Coconut Battery reports 4:33 remaining.

    TL/DR - Since disabling auto brightness and setting it manually, I have seen a HUGE jump in battery performance. And my eyes thank me as well. :) This has been my experience, but as always...YMMV.
  3. ascender thread starter macrumors 68020

    Dec 8, 2005
    That does sound like it exactly... What was strange was that its the first time I can remember seeing screen brightness listed as an app using significant battery.

    Thanks, will give it a go on manual brightness and see what happens.

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