Buzzy noise when on battery.

So i noticed that from around my keyboard area, theres a noticeable buzzing noise that alternates in pitch every second or so. It is there also while plugged in, but its alot harder to hear while plugged in vs while on battery.
Is this normal? Could it be capacitor whine?

 

Will check my notebook for you since we have the same one.

EDIT: Not having the same problem, there is absolutely no noise difference at all between battery and AC...

 

yeah but i had to literally put my ear to the keyboard to make out the sound when plugged in.
its a bit louder on battery

I wonder what it is.

 

http://forum.notebookreview.com/showpost.php?p=4979407&postcount=6

 

Oh, nice thanks.

On another note, its 2 am, really quiet, and while i was studying i heard a random high pitched screech/metallic sound come from my lappy
This is actually the second time i have heard this but the last one happened about 1-2 months ago and it was noisy around me so i just thought i heard it from the environment, since nothing happened to my laptop then, and nothing happened now. I also initially thought that it came from my external, but it wasn't even on, so I'm guessing that this definitely isnt normal, but what component is the most likely cause?

 

I had this problem before on my (crap) MSI, and on a few desktops too. I figured out it was the CPU, throttling, it stopped doing the screechy noise when i used the Overclock button on the latop. to remedy that i went in Bios and deactivated C states i think. You might not want to do that tho if you care about your battery. try it to test it out.