Lights Dimming.. Need help!

[gckless 5,000+ posts]

Check your ground on your amp. Make sure it's on bare metal and on the frame or as close to the frame as possible. Also check connection for corrosion. If your using ofc wire you might have some corrosion at your terminals. It's very common and will cause bad voltage. A good way to check your positive wire from the alt to the bat is to check the voltage straight off the pos stud on the back of the alt vs the battery and see if your losing voltage in between.
Sounds like a bad wire or messed up alt. Check those first and then check on a second battery or sell the yt and get you a bigger single battery. I've owned several optimas through the years

optimas=overated

Has nothing to do with the ground on the amp. Talking system voltage here.

But I'll agree with you that Optima's are no good. Not anymore anyway.

 

[swanginfleet]

Has nothing to do with the ground on the amp. Talking system voltage here.

I beg to differ considering his amp is the main component taxing his electrical system. Without a proper ground the amp isn't working efficiently as it's supposed to and may be drawing more power to compensate for the lack of connection.

Know like I said it's just a possibility, maybe not a great one but I wouldn't rule it out.

Like I said before it's probably your alternator.

 

[Dmac1991]

edit: 2x post

 

[Dmac1991]

For 1, you don't need a High Output alternator for the equipment you have.

How are your gains set?

Are you using bass boost?

and another thing. You said when you idle, voltage is at 13.9, turn your radio up, voltage drops .2 - .5, then you turn your headlights and it goes back up, that right there rules out your alternator being the problem.

The more electrical you use, your alternator compensates for it by charging your battery. Just sitting idle with barely anything on, your alternator isn't in use. Once you kick on the headlights and everything else, that tells your alternator that you needed more electrical, so it kicked on and jumped your voltage up.

When I first got into car audio, I had a shop install my system. Was a puny little 500 rms amp. They tuned it by ear, and I had horrid light dimming. So much where I drove at night with my system basically silent. Come to find out, they had the gain **** near maxed out, were using bass boost and only used 8 gauge wire.

Went and searched around on the forums a bit, and learned how to set my gains. Yanked all that old **** out. Got an 1300 rms amp, some 4 gauge wire, tuned my amp the right way, and my light dimming problems went away.

Optimas truly are junk no matter how much of a steal for the price you got it for. Replace your stock battery underhood with a better AGM battery. They're not costly. You can find a solid one for around $150 at your local Sears, Oreilly's, Autozone, etc... Make sure your ground is secured tightly to the chassis on a paint free surface and not corroded. Check your gains and make sure you aren't clipping the amp, causing excess current to be pulled which isn't good for your electrical system.

Report back to us after you have thoroughly checked your system

 

[adulbrich 5,000+ posts]

^^^Yea, really don't nead a HO alt. 120 is plenty for this system.