So I know this topic has been covered but my questions is a bit different. I have an optima yellow top, 160A alternator, 1/0 power and ground wires etc. But my lights still dim a bit. They dim when i have my system at almost full tilt when im sitting at idle but that i doubt could be cured due to the power my amps are drawing. My headlights dim at idle and when i start accelerating they brighten up (or when i jsut tap the gas in park or neutral). How can I fix this as its not affected by my sound system at all. Would I need to upgrade the wires to the headlights themselves or is there something im missing here?

Chances are your 160A alternator is not putting out 14v at idle. Most higher amperage alternators do not put out full voltage at lower RPMs.

Your options are:

1) Smaller pulley on alternator so it spins faster at idle. Bad idea as it spins faster all the time and will have a shortened lifespan.
2) Use a Jacobs Accuvolt on your stock electrical to keep it at 14+v all the time. Kinda pricey ($300+) for a minor problem.
3) Learn to live with it.

i have tested the output at the battery when the car is idling and it reads 14.65 . I also tested it using the 1/0 wire from the alt. and the ground connected to the block and got aroudn the same reading. The lights just dim slightly but im wondering if there is a fix for it?

have you done "the big 3" mod

Yes I have 1/0 from my engine to chassis and 1/0 from my battery to chassis. I also have 1/0 running from my alternator to my battery.

UH>>> You have a 2000x... That's the end of the discussion right there. That amp is capable of drawing well over 300A of current. A single battery and a moderately sized alternator isn't going to have a hope in keeping up.

You need more alternator and / or more battery.

x2
I have a big single battery and my alt will do in excess of 180a hot and good for 140a at idle. 1g wires everywhere. Running voltage is 14.8v and at idle I can make them dim pretty good. Revved up I can still make them dim. :D

The thing is they dim even without the 2000x and Tu-600 not hooked up? I know that with the 2000x and the Tu-600 running i am guranteed to experience dimming but with them not hooked up the headlights still are dimmer at idle.

btw dave does George have an email address, i was talking to him at the CSCS show on the weekend and wanted to get in contact with him.

wow- that's a lot of voltage at idle. What's the reading just above idle?

Considering this information, I don't think your headlights are "dimming" at idle but are simply getting brighter with the increased voltage above idle. Lightbulbs are dumb - feed them more voltage and they get brighter - until they burn up anyway..

When did you test the idling voltage?
It will be highest when just starting your car after sitting.
The car will be at higher RPM if the engine is cold.

Test the idling voltage on the car when it is fully warmed up and see if it is still 14.65 and then test it with the car's RPM's higher to see what the difference is.

If it's a major difference then Dukk hit it on the head.