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when using an external monitor with a macbook pro (clamshell mode) does the macbook have to stay plugged in to AC in order for the monitor to maintain display? And if so, how does that affect the battery to remain healthy?

when using an external monitor with a macbook pro (clamshell mode) does the macbook have to stay plugged in to AC in order for the external monitor to maintain display? And if so, how does that affect the battery to remain healthy (since you aren't supposed to keep it plugged in after it reaches 100%)?

MacBook Pro (13-inch Mid 2012), iOS 6.1.4

Posted on Sep 7, 2013 8:31 PM

Best reply

clintonfrombirmingham

Level 7

30,100 points

Posted on Sep 10, 2013 7:16 AM

The short answer...

...yes, you have to keep the power adapter plugged in to use the external monitor.

If you're using your MacBook Pro with th external monitor and the computer plugged in, you needn't worry about the computer 'overcharging' - it won't and it can't. I use my MacBook Pro plugged into my Apple Thunderbolt Display 97% of the time. I have a reminder set every two weeks to disconnect from mains and let the battery run down to 30-40% and then plug it back up. My battery health is still at 99% even after using this method for well over a year now.

Clinton

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19 replies

NiqueXyZ

Level 1

8 points

Apr 26, 2016 4:33 PM in response to Csound1

This is absolutely ridiculous...I was just recording in ProTools a moment ago, and while I was nailing this guitar part, someone accidentally unplugged the power cord to the MacBook Pro...It instantly threw it into sleep mode and stopped recording and screwed up everything! Surely there MUST be a way to disable this behavior? This is supposed to be a "Pro" machine after all, right?

steve359

Level 6

17,175 points

Apr 26, 2016 4:40 PM in response to NiqueXyZ

How old is the battery? How many times has the battery been run too low (accidental or not)?

A good battery should at most cause a slowdown of operating without external, not a shutdown.

If not the battery ... keep a keyboard and mouse plugged into USB to maintain a reason to not sleep. Any cheap keyboard and mouse will trigger the "stay awake".

NiqueXyZ

Level 1

8 points

Apr 26, 2016 4:51 PM in response to steve359

It doesn't have anything to do with the battery, I don't think.

The macbook is closed and using an external monitor.

For keyboard and mouse -- both are bluetooth.

Whenever I unplug the magSafe power cable it throws the computer into sleep mode automatically.

I'm guessing this is the *intended* behavior...I guess what I am asking for is how to disable this.

I don't want to disable sleep mode entirely but to have a 100% charged battery and then have someone accidentally trip the magSafe cord and have the computer sleep right away instantly, I think that's a bit ridiculous, especially since it's a magnetic cable and can come undone easily, at times.

I REALLY do not want this to happen again 🙂 🙂

If there is a checkbox somewhere that says something like "Prevent computer from sleeping on full battery power when connected to external display" I am not seeing it. IIRC, there is an option like this in Windows

bgood34

Level 1

4 points

Nov 9, 2016 8:08 AM in response to inquiring1mind

I just had to change my battery from having it plugged in during work every day, all day. I think letting it drain every couple of weeks is helpful and more than what I did but not a good answer

when using an external monitor with a macbook pro (clamshell mode) does the macbook have to stay plugged in to AC in order for the monitor to maintain display? And if so, how does that affect the battery to remain healthy?