External monitor not working when no AC plug?

[l3lack J4ck]

why is that when i unplug my power cord from my macbook pro (which i have a 22" widescreen display hooked to it) the external monitor turns off? It goes into no signal, even though i have 100% battery left? I usually have my macbook plugged in and this is kind of an annoyance when it accidentally comes unplugged.

Any way to keep the external on when mbp is not plugged in?


thanks

 

[j26]

Try Detect Displays in System Preferences and see if it spots the external monitor.

 

[plinden]

Any way to keep the external on when mbp is not plugged in?

thanks

No, that's just the way it works. You need to be plugged in to work with an external monitor.

 

[orangemacapple]

it'll work if you have the lid open.

open the lid and then unplug the ac. everything stays the same.

strange, i know.