Interesting Issue I wan into

anthlover · 02-13-2013, 10:39 PM

I ran into an interesting issue I found that I could not find documented. It Appears Macbook Pro Retina 15s will not Drive 2 Monitors via its 2 thunderbolt ports unless it is plugged into AC power, despite being at 100 percent battery charge. The Video Signal shutters to life then terminates.

Plugging into AC power resolves the issue. I thought this was a bit ODD. One display did not seem to be an issue.

If it matters the displays in Question were a pair of Dell U2410 24 Inch 1920x 1200 displays connected via Mini to regular Display cables connections.

Marlboro Man · 02-14-2013, 12:40 AM

The typo in the subject line led me to believe it was a networking issue…. On a more serious note, however, the behavior kind of makes sense. If you are using your macbook connected to a monitor (or two in this case), it would logically follow that there is an available power source to plug in the computer as well. I wouldn't think your laptop battery would last very long pushing two monitors that size anyway.

anthlover · 02-14-2013, 07:04 AM

LOL tired when I typed that

Suppose it makes sense but not very elegant interaction with the OS.

chabig · 02-14-2013, 02:56 PM

I have a 2011 13" MacBook Pro. It only drives my Cinema Display when it's plugged in. If I unplug the computer, the display goes dark. I never questioned the behavior.

DeltaMac · 02-14-2013, 03:14 PM

Years back, Powerbooks used to flash a message to plug in the power adapter when an external display was attached. No external video without the power adapter plugged in.
I don't think that's really a software issue.

anthlover · 02-14-2013, 04:22 PM

People use Projectors all the time off Battery Power and as I mentioned a single display was acceptable to the system.

All I meant is it would be nice if a message flashed on the screen as you said used to happen. And actually the image came on both displays very briefly and then shut off.

chabig · 02-14-2013, 04:55 PM

Apple says the computer must be plugged in:

http://support.apple.com/kb/HT3131

anthlover · 02-14-2013, 08:12 PM

Thank you for the link. I imagine having the lid closed was the difference in retrospect as the link indicates That with the Lid open it will do Battery for even both displays despite it not being good to leave it that way long.

02-13-2013, 10:39 PM	#1
anthlover Hall of Famer Join Date: Apr 2003 Posts: 2,671	Interesting Issue I wan into I ran into an interesting issue I found that I could not find documented. It Appears Macbook Pro Retina 15s will not Drive 2 Monitors via its 2 thunderbolt ports unless it is plugged into AC power, despite being at 100 percent battery charge. The Video Signal shutters to life then terminates. Plugging into AC power resolves the issue. I thought this was a bit ODD. One display did not seem to be an issue. If it matters the displays in Question were a pair of Dell U2410 24 Inch 1920x 1200 displays connected via Mini to regular Display cables connections. Last edited by anthlover; 02-13-2013 at 10:42 PM.

02-14-2013, 12:40 AM	#2
Marlboro Man Triple-A Player Join Date: Oct 2007 Posts: 199	The typo in the subject line led me to believe it was a networking issue…. On a more serious note, however, the behavior kind of makes sense. If you are using your macbook connected to a monitor (or two in this case), it would logically follow that there is an available power source to plug in the computer as well. I wouldn't think your laptop battery would last very long pushing two monitors that size anyway. __________________ "Enjoy every sandwich." - Warren Zevon

02-14-2013, 04:22 PM	#6
anthlover Hall of Famer Join Date: Apr 2003 Posts: 2,671	Projectors People use Projectors all the time off Battery Power and as I mentioned a single display was acceptable to the system. All I meant is it would be nice if a message flashed on the screen as you said used to happen. And actually the image came on both displays very briefly and then shut off.

02-14-2013, 08:12 PM	#8
anthlover Hall of Famer Join Date: Apr 2003 Posts: 2,671	Ty Thank you for the link. I imagine having the lid closed was the difference in retrospect as the link indicates That with the Lid open it will do Battery for even both displays despite it not being good to leave it that way long.

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02-14-2013, 07:04 AM	#3
anthlover Hall of Famer Join Date: Apr 2003 Posts: 2,671	LOL tired when I typed that Suppose it makes sense but not very elegant interaction with the OS.

02-14-2013, 02:56 PM	#4
chabig Hall of Famer Join Date: Jan 2002 Posts: 2,934	I have a 2011 13" MacBook Pro. It only drives my Cinema Display when it's plugged in. If I unplug the computer, the display goes dark. I never questioned the behavior.

02-14-2013, 03:14 PM	#5
DeltaMac League Commissioner Join Date: Jan 2002 Posts: 7,960	Years back, Powerbooks used to flash a message to plug in the power adapter when an external display was attached. No external video without the power adapter plugged in. I don't think that's really a software issue.

02-14-2013, 04:55 PM	#7
chabig Hall of Famer Join Date: Jan 2002 Posts: 2,934	Apple says the computer must be plugged in: http://support.apple.com/kb/HT3131