A little help with my setup...Thanks.

[PerfectCreature]

So, I'd like some opinions.
I just picked up a Rockford Fosgate Punch 400-4 for a killer deal, I practically robbed it.
I also picked up Phoenix Gold Rsd 6x9s and 5.25 component set. They are rated for 60 wrms each.
I will be getting all of this shortly.
It says that the amp draws 80 amps. My alternator is stock 105. I do not want to kill it by all means, I have a Grand Am, I know they have a lot of electrical stuff.
Can I also add my JBL amp (Which wants a total of 60 amps) and my alternator being fine?

So a break down. JBL wants 60 amps, Rockford wants 80 amps. JBL puts out 360RMS, Rockford would put out 60 per channel for a total of 240RMS.
So, that is a total of base-line 500watts RMS, but 140 amps.
Which should I follow. I do not want to burn up my alternator, I will however be doing the big three upgrade on this vehicle. My battery is just a regular plain-jane battery.

Basically, what I will be doing for the time being until I can get enough money to buy the subwoofers I want, is run just the 4 channel amp. I know that will be more than enough sound, but I also like the subwoofers to kind of fill it all in you know? Since the lowest that my 6x9s are rated to go is 55hz. That leaves a fair gap in bass, plus 6x9s wont give me the thump in the chest.
I had planned on adding the JBL amp in at a later time. Could I do this without killing my car or having my lights dim or what have you?

Thanks so much
Thanks.

[exalted512]

You'll be fine. Your lights might dim...but thats not a bad thing. Doing the big 3 would help for sure though!
-Cody

[Vital]

So 140amps being drawn while alternator is only putting out 105 is ok??

Not saying i disagree, more of a "looking for answer to how it works"

[KaosTsoc]

I would think that going over the amps that your car can produce will only fatigue the alt, and at some point might burn out. I would also think that the watts, and amps kind of go hand in hand. In order to produce watts you need amps.


Thanks.

[arun1963]

Just casue an amp is rated for 60amp doesn't mean its drawing anywhere close to that.

[catch22atplay]

Close to correct Kaos but it's volt*amps=watts

Exactly Arun

But let's take an extreme worse case scenario as an example. Let's assume both amps are class A and not class A/B and have an efficiency rating of 50% vs say 68% for a class A/B. Total wattage you estimated at 500. With a 50% efficiency rating this would require 1,000 watts input to the amps. 1000watts/14.4v=69.44amps. That's the actual current draw with this example.

To continue with the above example. Now if the amps are underrated watt wise and or if they were extremely robust they might peak at say 2x their continuous rating at 1,000 watts. This would require 2,000watts input to the amps which would draw 138.89amps during the peaks in music. Typically when the bass is really slamming hard from my experience.

So with the above you know that regular listening you're ok. And that when the bass hits hard you'll be relying on your battery to supply the added current. Since the continuous rating is well below the alternators rating you know your battery will be charged. But during the big bass hits you'll be robbing amps from the battery and the battery will not be charged during those short peaks. The peaks will also cause the lights to dim. Caps have gotten a bad rap because people don't understand them. But this is actually a perfect example of when to use a Cap.

I ran a 150amp/1,200 watt system with a stock 120amp alt. I had to replace the alt after 5 years and approx 180,000 miles. I had expected to replace it at 5 years or 150,000 miles before upgrading the audio system. So was pleasantly surprised it lasted as long as it did. I used the pos stock battery for the first 3 years and replaced it with a slightly better one. I never added a cap and wish i had to eliminate the light dimming. Other than that it was perfect. My Polk separates sounded fantastic and loud and the 2 JL subs slammed damn hard. I watched others on the freeway adjusting their mirrors as i got near or drove by them.

[KaosTsoc]

catch22, thanks. Yeah it was a quick post. Thanks for the correction. I ment to make it, but forgot.



Thanks.

[PerfectCreature]

Awesome, so. That pretty much says it. That under normal listening levels on 105 amps, I should be golden. However on strained loads (When I want to "show off") A cap should be used to help fight against dimming lights, but those will be expected.

Awesome. So, I will do the big three, and see how long my alternator will last I guess ha!