mike1954xxx

Q: MBP Connected to external monitor goes to sleep if power cord unplugged

I have an early 2011 MacBook Pro that is connected via Thunderbolt-to-DVI to an external Gateway monitor, working in clamshell mode.  If I disconnect the power cord, either at the MBP or from the UPS, it immediately goes to sleep.  Is there a fix for this?   Thanks.

MacBook Pro, OS X Mavericks (10.9)

Posted on Dec 13, 2013 6:03 AM

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Q: MBP Connected to external monitor goes to sleep if power cord unplugged

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  • by sanjampet,

    sanjampet sanjampet Dec 13, 2013 6:16 AM in response to mike1954xxx
    Level 5 (7,874 points)
    Dec 13, 2013 6:16 AM in response to mike1954xxx

    Check the battery healt/condition click the Apple logo in the menu bar holding the OPTION key, select system info, select power from the left columm, see if the condition is normal, if you have a high number of cycles.

    Maybe the battery can not supply enough current to support both.

    Maybe it needs replacing. You can take it to an Apple store genius bar for a free eveluation.

     

    You can try a smc reset see if that helps:

    http://support.apple.com/kb/HT3964

     

    Follow directions for a battery you sould not remove yourself.

     

    Also check this:

    http://support.apple.com/kb/HT5309

  • by mike1954xxx,

    mike1954xxx mike1954xxx Dec 13, 2013 6:35 AM in response to sanjampet
    Level 1 (9 points)
    iTunes
    Dec 13, 2013 6:35 AM in response to sanjampet

    Everything looks normal.  Here's what is reported in system info:

     

    Battery Information:

     

      Charge Information:

      Charge Remaining (mAh):          5478

      Fully Charged:          Yes

      Charging:          No

      Full Charge Capacity (mAh):          5553

      Health Information:

      Cycle Count:          158

      Condition:          Normal

      Battery Installed:          Yes

      Amperage (mA):          0

      Voltage (mV):          12464

     

    System Power Settings:

     

      AC Power:

      System Sleep Timer (Minutes):          0

      Disk Sleep Timer (Minutes):          10

      Display Sleep Timer (Minutes):          0

      Wake on AC Change:          No

      Wake on Clamshell Open:          Yes

      Wake on LAN:          Yes

      Current Power Source:          Yes

      Display Sleep Uses Dim:          Yes

      PrioritizeNetworkReachabilityOverSleep:          0

      Standby Delay:          4200

      Standby Enabled:          0

      Battery Power:

      System Sleep Timer (Minutes):          10

      Disk Sleep Timer (Minutes):          10

      Display Sleep Timer (Minutes):          10

      Wake on AC Change:          No

      Wake on Clamshell Open:          Yes

      Display Sleep Uses Dim:          Yes

      Reduce Brightness:          Yes

      Standby Delay:          4200

      Standby Enabled:          0

     

    I wonder if it's one of the sytem power settings?  I only recently started using the MBP heavily, replacing a Win PC (I'd been lobbying the boss - my wife - for an iMac for awhile but she balked at the cost so I finally decided to appropriate the MBP for work) so am still learning some of the nuances and differences between the Mac and Windows.

  • by Wayne Contello,

    Wayne Contello Wayne Contello Dec 13, 2013 6:39 AM in response to mike1954xxx
    Level 6 (19,267 points)
    iWork
    Dec 13, 2013 6:39 AM in response to mike1954xxx

    Mike,

     

    Why would you want to drive an external monitor while running from the battery?  It will discharge the battery quicker, and shorten the life of the battery

  • by mike1954xxx,

    mike1954xxx mike1954xxx Dec 13, 2013 6:46 AM in response to Wayne Contello
    Level 1 (9 points)
    iTunes
    Dec 13, 2013 6:46 AM in response to Wayne Contello

    It's not so much that I want to take it off A/C power.  I first noticed what seemed odd behavior when I was still transitioning from the PC to the Mac.  I had both connected to the monitor and if I switched the display to the PC the Mac would go to sleep.  Then I noted that behavior if I happened to unplug the Mac's power for some reason, say to move it on my desk.  I had also read some comments about its being good to unplug the A/C power periodically in the interest of maintaining the battery life for when A/C isn't avalable.  All things equal, I'm perfectly happy to leave it plugged in all the time.

  • by Wayne Contello,

    Wayne Contello Wayne Contello Dec 13, 2013 6:52 AM in response to mike1954xxx
    Level 6 (19,267 points)
    iWork
    Dec 13, 2013 6:52 AM in response to mike1954xxx

    Mike,

     

    I used to write embedded firmware for gas gauge ICs (at Texas Instruments) which are the device that make a smart battery smart AND are the device in your notebook computer that maintain the battery.

     

    Do NOT wate charge cycles on fully discharging the battery.  When possible run on the charger.  Use the battery when AC power is not available.

     

    I have my MacBook Pro connected to an external monitor and I disconnected the AC Adapter.  The machine stayed on and awake (the MacBooks' display dimmed).

     

    The only settings I am aware of for this are in "Sytem Preferences > Energy Saver"

  • by clintonfrombirmingham,

    clintonfrombirmingham clintonfrombirmingham Dec 13, 2013 6:54 AM in response to mike1954xxx
    Level 7 (30,009 points)
    Mac OS X
    Dec 13, 2013 6:54 AM in response to mike1954xxx

    To be honest - that's the way it's supposed to work. Anytime your MacBook Pro is not plugged into a power source, the Apple Thunderbolt Display will not work.

     

    Just the way it's always been...

     

    Clinton

  • by mike1954xxx,

    mike1954xxx mike1954xxx Dec 13, 2013 6:56 AM in response to Wayne Contello
    Level 1 (9 points)
    iTunes
    Dec 13, 2013 6:56 AM in response to Wayne Contello

    Thanks, Wayne.  I had checked the Energy Saver preferences and didn't really see anything pertinent.  I won't worry about it anymore.  As much as anything I was simply curious about it, as it didn't seem especially logical for it to work the way it does.  I do love doing my work on the Mac now, though I do have to use Windows (running under Parallels) for too much of my work.

  • by mike1954xxx,

    mike1954xxx mike1954xxx Dec 13, 2013 6:58 AM in response to clintonfrombirmingham
    Level 1 (9 points)
    iTunes
    Dec 13, 2013 6:58 AM in response to clintonfrombirmingham

    Ahhhh....well, that clears that up, Clinton.  I definitely won't give it another thought!  Thanks.

  • by clintonfrombirmingham,Solvedanswer

    clintonfrombirmingham clintonfrombirmingham Dec 13, 2013 7:15 AM in response to mike1954xxx
    Level 7 (30,009 points)
    Mac OS X
    Dec 13, 2013 7:15 AM in response to mike1954xxx

    Yeah, I 'discovered' this feature about a year and a half ago when the installer came in to hook up my new modem. I let him fiddle around a bit and my screen went blank. I checked all of the connection and could not figure out what was wrong. Then I noticed my Y adapter had come loose and the I was powered up. Plugged it back in and my Display was suddenly on again!

     

    Just the way it works - not sure if it's documented or not!

     

    But you've found your answer...

     

    Clinton

  • by LittlePagoda,

    LittlePagoda LittlePagoda Dec 11, 2014 5:10 PM in response to mike1954xxx
    Level 1 (0 points)
    Dec 11, 2014 5:10 PM in response to mike1954xxx

    Agree that Clinton solved this issue. But I am still wondering if there is a way to modify the setting? Today, the power went out while I was working. This is the same as my Macbook Air (mid-2012, Yosemite) being disconnected from the charger. The machine went to sleep immediately as it was operating in clamshell mode driving a display port monitor. I was in the middle of installing MS-Office Updates and Adobe Updates. It appeared to be a true sleep and everything came back fine when I opened the clam shell. I would prefer a warning before the sleep, It could say, "Your AC power has been disconnected. Your system will go to sleep in 10 seconds. Press "Wait" to stay awake for 60 seconds." Of course, Apple would never be that wordy, but that's the gist of it.

  • by penx,

    penx penx Jun 23, 2015 7:02 AM in response to mike1954xxx
    Level 1 (120 points)
    Jun 23, 2015 7:02 AM in response to mike1954xxx

    I also have this issue (MacBook Pro Retina, 15-inch, Late 2013), and I don't think it's correct to say that this is by design to save battery life:

     

    It works fine if the MacBook Pro is opened, you can unplug the power without any issue. The issue only occurs when in clamshell mode. I don't see any logical reason Apple would intentionally make it work when the laptop is open but not when it's closed, therefore I think this is a bug.

     

    I agree that you should try keep your laptop plugged in when using an external display, but there are times when this is not possible - i.e. the power slips out or you need to temporarily use your power adapter for a second laptop.

     

    EDIT:

     

    Though Apple do specifically list it here:

    Requirements for closed-display mode

    Power adapter

    https://support.apple.com/en-gb/HT201834

  • by ipstone,

    ipstone ipstone Apr 1, 2016 6:20 AM in response to penx
    Level 1 (4 points)
    Apr 1, 2016 6:20 AM in response to penx

    I had the same issue here on a macbook air - I think this should be a togglable features/setup in preference:

     

    in my case I used the laptop in closed lid on a rack with external monitors, keyboards etc :

         but when I would like to take the laptop to work elsewhere, once power cord 'unplugged':

              because it's magnetic based (very easy), then the computer went to sleep:

                   then making things worse:

                           unplug other usb port, halt the system, that I have to reboot the computer

                        - otherwise the screen keeps blank, wouldn't wake up from sleep!