I have the MacBook Air, and on the charger, there is a LED that is red-orange when charging, and green when charged. Is there any way to change the color of that? To, for instance, make it red when battery power is from 0-25, dark orange when the battery is 25-50, etc.?
I don't think that it could be possible to "change the color" of charger plug led easily without destroying it. It's hardwired. If you are good enough to work with soldering iron under microscope you could.