I just installed a 200amp alternator on my 2005 jetta (old style), did the big 3 with some 1/0, and ran 1/0 power to the trunk. I have a new optima 34r red top. I'm running a 12" shocker super xtreme with an earthquake ph-d2. When I crank it up, the headlights dim real bad. On a steady tone, they stay dim, so I don't think it's the alternator reacting slow. They MAY brighten very slightly on a steady tone, but it's hardly noticeable, if anything at all. The dash will dim slightly also.
If I were to compare it to my old 95' beretta with the stock alt and 2 batteries, the dimming seems worse. This is all while driving. I have no idea what it could be.
I few idea's I have:
-bad ground at the amp (although I don't know why I'm even considering it :\ )
-car's computer limiting output.
-battery is bad. Doubtful because the car cranks over great, but, it was completely drained due to the old alternator going bad. Charged it with 12amps for about 30-60 mins, then 8amps the rest of the way.
-it's just the way it's going to be
I expect some headlight dimming, but not at the level it is now. Not to mention the dashboard.
But as I said, I really don't have a clue.
The first car off battery voltage I got was 12.28-12.35, it was not directly on the battery posts, but on the terminals connected to them. I turned the car on and got a 14.42-14.45 at idle and 2krpm, directly on the posts. Then I measured again directly on the posts with the car off and got a 12.53ish.
Additionally, something came on when the car was running, sounded like a fan (but it wasn't the radiator fan.) I'm pretty sure it was some secondary air intake thing, came from towards the bottom of the engine. I've read about it before but forgot what it's called. Anyways, the voltage dropped to the low-mid 12's then back up to 14 while it was still on I believe. I'm going to get some reading with the sub playing.
I disconnected the battery chassis ground and hooked up my charger with a 2amp charge and the charger reads 14.8 volts, and 80% charge and rising quickly. With my charger, the battery% display climbs very quickly until it get's to the actual level of the battery, then the display slows down to actual charging speed. Maybe there is a slight, but abnormal draw when my car is off?
15.2v and 88% is what it steadied at. Voltage is a little high according to the optima website, but there's nothing I can do about that.