Battery or Alternator? help

[ccm2001]

Weird problem I am having. When I use my power windows or turn my HIDs on or w.e uses power , my idle drops a little like it want to die but does not die. Is my Battery Dieng? Also no CEL. 03/sport slt

 

[4FordFamily]

If either, I would vote alternator.

 

[ccm2001]

Usual sign of a bad alternator is the battery light? But no lights on the dash

 

[Number4]

As I understand, at idle, the alternator isn't charging the battery. Could be a battery, alternator or simply wiring.

 

[wifes2011xlt]

How old is the battery? If you don't know, probably should replace it anyways. While you're at the auto parts store, get the alternator tested.