battery or alternator problem?

[92xltcobrastatus]

at idle my battery dash guage is on the "N" part of "Normal" if i rev it up slightly my headlights get brighter as it goes back to idle speed they dim its even worse when i turn the heater on...whie driving it seems to be charging great (the guage is on the "L" part of normal on the pendulum of the guage) i should get a multimeter but someone just stole my good fluke one and havent been able to pick one up yet...ive checked by battery connections and everything is nice and tight without a meter any guesses? is it just cuz its getting cold? the alternator isnt that old "couple years" maybe but the battery is only a month old any help would be great you smart smart guru explorer gods!

 

[walterd140]

Mine does the same thing, but I think it's because I have added a new radio & fog lights. Also when at idle, if I turn the blower on full I get a drop. If you have added more electronics, you could solve the issue with a higher amp alternater. Otherwise it is not a big deal (for me at least)

 

[BrooklynBay]

You could go to a place like Autozone to have them check your alternator, and load test the battery.