Clamshell mode running without power?

[raymondu999]

Hi all... I have just recently begun to notice that if I'm not running on AC power, my MBP refuses to do clamshell mode😕 It just goes to sleep when closed. However, when it's running on AC power, it stays awake. Is this the behavior that it's supposed to exhibit, or am I missing something?

 

[nerdish]

Hi all... I have just recently begun to notice that if I'm not running on AC power, my MBP refuses to do clamshell mode😕 It just goes to sleep when closed. However, when it's running on AC power, it stays awake. Is this the behavior that it's supposed to exhibit, or am I missing something?

Thats how it works!

No AC = it will sleep.

 

[Consultant]

You might need new battery.
Have you calibrated your battery?

 

[halfbelgian]

Hi all... I have just recently begun to notice that if I'm not running on AC power, my MBP refuses to do clamshell mode😕 It just goes to sleep when closed. However, when it's running on AC power, it stays awake. Is this the behavior that it's supposed to exhibit, or am I missing something?

http://support.apple.com/kb/HT3131?viewlocale=en_US

Apple Portables: How to use your computer in closed clamshell (display closed) mode with an external display

Make sure the computer is plugged in to an outlet using the AC power adapter.

 

[kolax]

Use InsomniaX to disable sleep so you can run it with the lid closed.

I have it set to open at start up, and have the key combo "CTRL ALT =" to enable and disable lid sleep. Really useful, and means you don't have to put your Mac to sleep then wake it for clamshell mode to work.

It'll solve your problem with the battery anyway.