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Old 04-05-2007, 03:27 AM   #1
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Default Sub setup & recommendations

I have a pair of Sony 1200W Xplod subwoofers in a box with a wall between them. On top of the box, I put a Rockford Fosgate P801 2400W amp with two 1.5 farad capacitors.

Today, I tried charging the capacitors with a resistor on the positive line, but the power trickled so slowly up to 5.36V, and when it went up to 5.37V, it quickly went back down to 5.36V. I took off the resistor and tapped the positive on the + lead of the cap a few times, as I had been instructed by a car audio installation guy. He called it "charging the cap like in the old days." My multimeter showed 11.56V, but it quickly sank down.

This is what a cap is supposed to do, it seems, but how many times do you think I'm supposed to tap the cap to ~12V before I can permanently attach it? I just charged the capacitors with jumper cables, but there'* going to be a 4AWG line with a 60A fuse going to the amp & caps. Should I run the 4AWG cable from an Optima in the trunk to the amp, and then the same cable to the battery from the alternator?

Also, I need recommendations on an alternator. I've been thinking of a dual output alternator for 1 YellowTop Optima in the back and 1 standard-or-so battery in the front. That'* all I've got for now. It'* probably too late for me to think straight enough about what I'm writing, but I'm excited about getting my sound system put together.
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Old 04-05-2007, 03:44 AM   #2
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honestly you should just ditch both caps. if your main power wire is 4 ga with a 60 amp fuse you definately have no need for caps.

Yes you need to run a wire from the battery + to the back. Although I would skip the caps and go directly to the amp.

If you complete the big 3 and have a good ground on the amp, there is no need for the caps. If you are still experiencing dimming then you need to look into a larger output alt.
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Old 04-05-2007, 04:08 AM   #3
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What if I were to run the stock alternator with a Duralast battery, 2 caps and the setup? Too insane?
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Old 04-05-2007, 04:15 AM   #4
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Quote:
Originally Posted by radomirthegreat
What if I were to run the stock alternator with a Duralast battery, 2 caps and the setup? Too insane?
I would still drop the caps and complete the big 3 instead. Then get a bigger alt or better battery if you are having issues.

read this
http://www.forum.realmofexcursion.co...ad.php?t=17970
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Old 04-05-2007, 09:10 AM   #5
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The cap is simply a band-aid, it covers up your problems, but doesn't fix them. Your still putting too high of a drain on your electrical system
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Old 04-05-2007, 02:57 PM   #6
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Considering that I'd need a bigger alternator anyway, couldn't I just keep the caps? They're already mounted on the sub box, and they look "snazzy." No, they don't match either the subs or the amp, but they still look nice. Couldn't I just run them for the heck of it? They don't really need to do much at all, but why the need to take them out? Do they do anything bad? I can't imagine that they do.
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Old 04-05-2007, 03:05 PM   #7
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no, they do not hinder anything at all, you can leave them in if you like them
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Old 04-05-2007, 03:28 PM   #8
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From the link:
"It should be clear that if the voltage doesnít drop the caps donít do anything. The voltage MUST drop for them to start discharging."

I read the page, and it'* very informative. I like how clearly and professionally everything was explained. It seems unfortunate that caps don't do much at all, so I'll just not mention them often.

But for now, I have a 2400W RF amp with dual 1200W Sony subs. There are 4AWG wires running down the length of the car, and I'd like to put a YellowTop Optima in the back. Do you have recommendations for batteries or alternators I should use?
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Old 04-05-2007, 04:32 PM   #9
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Old 04-05-2007, 11:45 PM   #10
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The cap is simply a band-aid, it covers up your problems, but doesn't fix them. Your still putting too high of a drain on your electrical system
_________________
-Aaron-


I agree there is a high drain on the electrical system. However, I don't agree with the band-aid statement. Once the cap is charged it supplies a more constant usable voltage to the amps. The electical system has to run power windows, AC, headlights, defroster etc.. and the cap just supplies power to the amp(*).

My .02

Tim
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