WHINING, LOWER IDLE

For about 1 month I have been getting a "whining" sound from my engine compartment. To me its sounds like increased load on the belts. Since it has started my idle has gone from a normal of around 950 to about 750 if not moving.
It also gets louder/lower idle if I turn on the rear defroster. It continues and gets a little louder with speed up to around 25 to 30 mph and after that I cannot specifically hear it.

I did change the battery and headlights in the last month. It does also seem like my dash lights will "flicker" now intermittantly. Other than that I have not had any codes or problems recently.

Do I have something electrical that is on the way to failing? Or some other problem? Your answers are appreciated.