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  1. #1
    MBP: external monitor won't wake up
    I have a very annoying problem with my 13 inch Macbook Pro mid 12 running Mac Os 10.13.6 and an iyama ProLite E2783QSU 24” display connected via display port.

    When my Macbook goes to sleep while NOT connected to the power chord, the external display does not wake up, once I wake up the MBP. I notice that the MBP still recognises that an external monitor is connected since I can move the mouse into the area where the external monitor is supposed to be.

    (However, the external monitor DOES wake up after sleep when the MBP is connected to the power chord.
    Of course I don’t always want to keep my MBP connected to power cause this will decrease battery life, right?)

    Turning the monitor off and on again does not solve the problem, nor does unplugging and reconnecting the monitor. The only way to solve this is to restart my MBP which is really annoying as you can imagine.

    Connecting the monitor via HDMI is not an option since this somehow restricts the resolution of my external monitor to 1980x1080 but I want to have it in 2560 x 1440.
    Resetting PRAM and SMC did not solve this problem.

    This problem did not occur with my older external monitor (which was connected via a HDMI adapter).

    Can anyone please help me with this?

    Cheers!

  2. #2
    MBP: external monitor won't wake up
    chscag's Avatar
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    Welcome to our forums.

    Apple has clearly stated that when operating a portable Mac (MacBook, MacBook Pro, MacBook Air) on battery alone, an attached display (monitor) will not perform normally. Also, Apple has stated that you can not operate the same Mac from battery in clamshell mode with an attached monitor.

    To make a long story short.... your MacBook Pro and Monitor are performing normally the way they're supposed to.

  3. #3
    MBP: external monitor won't wake up
    RavingMac's Avatar
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    Also, I read the advice about not leaving Laptops on charge, but I always leave my Laptops plugged in . . . always. This included a Gateway Laptop, 2 MacBooks (2006 and 2008 vintage), 2010 MBA, 2007 MBP, 2012 MBP, and a series of Dell Laptops at work.

    Out of that group I had one battery go bad in roughly 20 years of using Laptops (the 2007 MBP). I will accept that as reasonable cost for the convenience of leaving the devices on charge

    EDIT: Also, I really need to get around to editing my Mac Specs in the sidebar. Seriously out of date here
    I've always wanted to be smart, handsome and modest. But, I guess I'll have to be satisfied with two out of three . . .

  4. #4
    MBP: external monitor won't wake up
    chscag's Avatar
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    This included a Gateway Laptop,
    Hey Mike.....

    Remember what we used to call a Gateway computer? Does the term "Cow Box" bring back any memories?

  5. #5
    MBP: external monitor won't wake up
    MacInWin's Avatar
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    Of course I don’t always want to keep my MBP connected to power cause this will decrease battery life, right?
    Well, yes and no. Theoretically, battery life can be extended by holding the battery closer to 80% than 100%, but the difference is pretty small. From these experts: How to Prolong Lithium-based Batteries - Battery University you can read this:
    The question is asked, “Should I disconnect my laptop from the power grid when not in use?” Under normal circumstances this should not be necessary because charging stops when the Li-ion battery is full. A topping charge is only applied when the battery voltage drops to a certain level. Most users do not remove the AC power, and this practice is safe.
    I won't go into all the chemistry, but a good Li-ion battery should last 300-500 full discharges before decay sets in. Assuming you don't drive the battery all the way down every day (which is a really BAD practice and will kill it very quickly), but maybe go to 50% every day, 500 cycles should last you 1000 days before the battery starts to decay for that reason. But all Li-ion batteries start to decay two years after manufacture, so even if the battery were made the day before you got it, it would start decaying about 730 days later. Given that the battery maker makes it, ships it to Apple who puts it in and then ships it to you or to the store, let's say the battery has a more practical life of 700 days before the chemical decay sets in. So if you push it to 50% each day, then recharge over night, the chemistry will start the decay before the usage does, by almost a year (300 days or so). And in any case, the rate of decay for both reasons is pretty small at first. I've used Li-ion batteries for 5 years before I've seen any practical, meaningful decay.

    I leave my MBP on mains all day and my battery is showing that it is 335 days old, with a current full charge of 8698 mAh as opposed to the design capacity of 8755 mAh, which is 99.3%. I have only used 11 full cycles on the battery in that time. (I used coconutBattery for the data.)

    So, technically, yes, you can extend your battery by not leaving it on mains all the time, but in practice, that difference is meaningless. You can extend the life more by not depleting the battery all the way, or at least minimizing the depletions.
    Jake

  6. #6
    MBP: external monitor won't wake up
    RavingMac's Avatar
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    Quote Originally Posted by chscag View Post
    Hey Mike.....

    Remember what we used to call a Gateway computer? Does the term "Cow Box" bring back any memories?
    Absolutely
    I've always wanted to be smart, handsome and modest. But, I guess I'll have to be satisfied with two out of three . . .

  7. #7
    MBP: external monitor won't wake up
    pm-r's Avatar
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    Of course I don’t always want to keep my MBP connected to power cause this will decrease battery life, right?
    Also, I read the advice about not leaving Laptops on charge, but I always leave my Laptops plugged in . . . always.
    In addition to what was already mentioned by Jake, don't forget that computer battery technology has changed somewhat drastically over the last few years and old methods and suggestions often don't apply or work as they used to these days.

    In fact, working a current design computer battery down to its minimum charge state continually and then fully charging them can actually kill them quicker than leaving them plugged into AC power.



    - Patrick
    ======
    Last edited by pm-r; 07-10-2019 at 06:28 PM.

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