Re: 2002 Chevy Trailblazer / suggestions
The stock alternator (model AD-244) is rated for 150 amps, according to my service manual.
You definitely shouldn't be getting dimming with just 500 watts. Dirty or otherwise crappy connections on the battery could cause it. I run 700 watts in my Jimmy without even a hint of dimming, with all stock electrical, stock battery. Have you checked your battery, is it healthy?
I believe the consensus is you should do the Big 3 for 1500 watts. You could add another battery in the back if you still get dimming after the Big 3. But for 500 watts none of this should be necessary.
Thou hath not so much brain as ear wax.