I recently installed some subs and an amplifier in my 2007 Canyon with the 3.7L. In order to fix the dimming, I installed a small XS battery under the seat. I also installed a digital volt meter on the amp itself. I bought a brand new main battery and new terminals. When I first started the truck, the meter would go up to 15.3 and stay there for 30 seconds. Then the voltage slowly drops and stays at 14.7 for a minute and then it slowly drops down to 12.8 and stays there. Now when the bass hits, my voltage drops down to 11.6.
I figured the voltage regulator was shot, so I went out and bought a new alternator. I installed it today. It does the same exact thing as the old one. It doesn't go up to 15.3 anymore but it still sinks down to 12.8(battery voltage) and stays there. Why isnt the alternator kicking? Every once in awhile, I will see it go up to 13.7 and then sink back down to 12.8. Even with the truck running, AC on, radio playing, it will stay at 12.8. It goes down when the bass hits but then back up to 12.8. When its on 12.8 volts, it will drop down to 11.5 volts. When I play the music right after I start the truck up and have 14.5 volts, the voltage will only drop down to 13.2 or so. How can I get it to stay like that?