For those of you that can help me, I have a stereo system that draws a done of power and my volts when I am at idle and the stereo is cranked up is in the low 11 range so I believe the alternator needs to be upgraded but I am not sure? Could it be the battery needs to be upgrade to Optium? If I am not mistaken when the car is running it is on the alternator not battery but I could be wrong? Or lastly I called the installer in Georgia I am in Florida now and says could be a ground which I don't think that's the case because if the system is not cranked up the volts are fine but when it is cranked and AC on everything is fine until I get to a light and at idle it drops from 13 - 14 range to 10-12 range. Thanks in adavance.

 

It could be a ground, but more likely you need a alternator that puts out more amps. Here's a quite basic explaination of the system:

Battery
Stores power, when charged is around 12 volts. Usually has around 110 Amp hours, whichs means it can put out 110 amps for 1 hour or 1 amp for 110 hours. For example, if you stereo draws 20 amps, you should be able to listen to it for about 5 hours and still start the vehicle (barely), any longer and it wont start.

Alternator
Charges battery while engine is running, it elevates voltage to over 12 volts, usually 13-14.5 or so. If the voltage is not higher when you car is running than when it is not, you are not charging your battery and it will die eventually. As the load in amps increases, the voltage drops, if you are seeing low voltages it means the altenator can't keep up with the loads, meaning you are steady losing batttery power; however, if appears that the voltage increases when you are not at idle, at those times you are charging the battery. Basically at idle you are discharging you battery and above it you are charging it. There is a good chance you chould drive like this and never have any battery problems, but you alternator will fail prematurely becuase it is putting out more current than it was designed for.

If the voltage looks ok when stereo is not running, it is probably not a ground. A good thing to do would be to determine you power requirements by measuring it with a ampmeter or you can calc it if you now how many watts you want to put out (constant, not peak wattage).

 

So if that is true VENDORS does anyone sell a higher output alternator for the C6?

 

I curious about how many watts your system is (continuous and peak)? I don't know what the output of the stock alternator is...

 

If the stereo itself does not have problems when playing loud, (premature clipping/distortion) it's not likely a ground.

On the other hand, if your stereo draws more current than your stock alternator/battery can provide, you either have a poorly designed system or you are almost deaf or about to be deaf.

 

Got a JL audio 500/1 for the subs and a 450/4 for the rest and it rocks.

 

That shouldn't be a problem. Does the voltmeter dip below 12 just on the peaks of loud music or is it down there more steadily? If it's anything more than peaks, there must be an issue somewhere.

 

If those are continuous outputs it is extremely high, 500*1+450*4=2300 watts/12=191.67 amps. I'm pretty sure those are peak numbers, so he is maybe at 1/4 that, which is still a substantial 50 amps. After a start the battery typicals draws 20-30 amps for awhile, so that puts our load at 70-80 amps + all the other electrical stuff on C6....

 

The easiest thing would be to put in the best Optima battery you can fit. Really with a system that draws a lot, it probably needs both an upgrade to the alt and battery.

But a better battery alone would help. Recheck and retighten the main connections after some driving to make sure there are no ground problems.

I'd put in the best Optima. Take it out at night with lights, stereo and a few more things on. See if it runs into problems. If the HIDs stay bright and no warnings come on, probably will be OK.