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Discussion Starter · #1 ·
I hope this is the right place to post this, didn't feel that there was a place in the installation section for this question...

so i recently bought a Stinger SPC5010 10 farad capacitor in hope to help take some of the strain off my electrical system(ive got a subaru impreza 2.5i with stock alternator and battery and plan on powering a mono 1200w and a 4-channel 160X4 ) but im not sure how to wire it up.

It has 4 round 1/0 gauge connections with 2 of them labeled "positive" and 2 labeled "negative". They're the type of connections you find on an amplifier power and ground. Im wondering if it is designed for two separate sets of power and grounds to run through it or what? Should i run the wire from the battery to one "positive" and then another wire from the other "positive" to to the amp with a ground coming out of one of the "negative" connections going to the chassis?

Any help would be nice, thanks
 

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Discussion Starter · #3 ·
Thanks for the reference, ive definetly got some studying to do

I dont really understand what u mean by it adds more strain though?? I was under the impression that a cap will aid in providing power to the amp when it demands more power than the battery and alternater can provide and thus will help prevent such things as headlight dim (which is the reason i thought i needed a cap)

But anyways i guess my original question was more or less does anyone have any experience with capacitors with round inputs rather than the normal type which is a pole that u can stack mutiple O shaped crimps one top of each other.
 

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Thanks for the reference, ive definetly got some studying to do

I dont really understand what u mean by it adds more strain though?? I was under the impression that a cap will aid in providing power to the amp when it demands more power than the battery and alternater can provide and thus will help prevent such things as headlight dim (which is the reason i thought i needed a cap)

But anyways i guess my original question was more or less does anyone have any experience with capacitors with round inputs rather than the normal type which is a pole that u can stack mutiple O shaped crimps one top of each other.
The reason the capacitor will cause more of a strain on your car's electrical system is because when that capacitor "gives" the amp the current it needs, it will need to recharge, that's just what caps do. Well when you drain it, and it becomes empty, it will demand current from the battery. You follow?

So when the cap is empty, not only will you have the big current demand of the amplifier (and the rest of the car), but you will ALSO have the current demand of the capacitor, thus draining the battery even more. So when the capacitor is drained, you're actually hurting your car's electrical system even more so than if you didn't have one.

Do you kinda see what I'm saying? Yes, the capacitor will provide current for the amplifier...... for about what, 2 seconds? I'm not disagreeing with you there, it will do it's job..... but what I'm trying to say is that an upgraded battery/alternator combo will actually FIX your problem, instead of just "covering it up".

If I were you, try to sell the capacitor to some newb (no offense :) ) and spend the money you get for it on a nice alternator.

If you do end up going the alternator route, then we'll talk more. Hope that helps. (sorry for the long post....)
 

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Installing a cap { w/diagram }

Car Audio Capacitor Installation

quote:

They are wired with the negative terminal to ground and the positive terminal wired inline with the amplifier's main power lead. Preferably as close as possible to the amplifier.

quote:

Truth about caps...

The Truth About Power Capacitors

Silly damn engineer loaded my amp down with system drainers [ blue -n- black ones ].

Once I get the caps unsoldered the power should just go to the speakers [ Bwa ha ha ha ! ]



From BCAE

quote>

When using very large capacitors (1/2 farad or more) in your car, the capacitor partially discharges into the amplifier's power supply when the voltage from the alternator or battery starts to fall. Keep in mind that the discharge is only for a fraction of a second. The capacitor can not act like a battery. It only serves to fill in what would otherwise be very small dips in the supply voltage.

quote>
 

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The reason the capacitor will cause more of a strain on your car's electrical system is because when that capacitor "gives" the amp the current it needs, it will need to recharge, that's just what caps do. Well when you drain it, and it becomes empty, it will demand current from the battery. You follow?
Yeah, but the key question is: WHEN is it recharging?

It recharges when the voltage begins to rebound... ie. when the amp stops drawing current. In between transients and such. A cap will actually REDUCE the "strain" because the peak draws will no longer be as large.

Also keep in mind that it's a zero sum game. The cap isn't producing power and it's not dissipating power (except for whatever leakage current exists, which should be negligible in a healthy cap, and its ESR which should also be a non-issue). So the total drain from the electrical system over time is no different with or without the cap.
 

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Installing a cap { w/diagram }

Silly damn engineer loaded my amp down with system strainers [ blue -n- black ones ].

Once I get the caps unsoldered the power should just go to the speakers [ Bwa ha ha ha ! ]

I think I am going to go solar for my audio system, and remove the caps of course. No more strain on my electrical system then. :)
 

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Rootbeer,

You would be FAR better off with a high amp alt... About what did you pay for that huge cap?

If you GIS Maniac Electric Motors, they have a 140A alt for you for about 180$(w/core)..!

I just put one on my 00' Impreza and kept the stock alt in case something happens.. so I payed ~200$

Caps have their place, but it's not really in a cars charging system anymore... I guess there was a time, but with todays amps and all... It's like everyone is saying...

Do yourself another favor and search out every ground you can find on the car and freshen it up.. un-bolt it, sand off some paint the the circle left from the terminal, apply some dielectric grease and bolt it back up...

Subies are known for lame ground connections... You might be surprised that there could be a few MPG and maybe a few HP, in just freshening up the grounds.. So any, under the hood, under the motor (there are a few on the rad support down low) and in the kick panels and center cluster area.. Finding the ECU ground is another big one..

All of this will help toward a better charging system... you need 3 things to move a vehicle... Air, fuel and spark.. the better you make any of those systems the better it will run...

also search out "the big 3" and try and determine if your car is setup with it...
 

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The reason that particular cap has 2 connections for each terminal, it's meant to use one as an input and one as an output. the in and out are paralleled which is fine, normally a cap would have one terminal for positive and one for negative and you'd use 2 wires to each- yours just makes installation easier.

Positive in from battery to one part of the (+) terminal, positive out to your amp(s) from the other part of the (+) terminal.

One part of the (-) terminal goes to ground, the other part of the (-) terminal goes to the (-) of your amp(s).

You'll want to charge the cap before completing the wiring, you can either use a resistor in series or what I've always done is use a light bulb (a test light works great) in series with one of the terminals. When the light goes out, the cap is charged. Most capacitors discharge to almost a dead short, you don't want to wire a dead short into your charging system. That's why you charge it first.
[edit] Your cap has a "remote" input also, so it might have electronics on board to aid the initial charge. I'm not sure. The remote terminal may only trigger the power meter. I'd charge it manually first just in case.
 

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Discussion Starter · #10 ·
Thanks for all this great info and thanks for the heads up on the alternator Aaron'z 2.5RS/WRX, i definitely might look into that. Was it a pain to install the new alt?

The whole reason i bought the cap in the first place was because i was new to ebay and there was all this stuff at totally rad prices and i didnt really have the cash to put into a new alt and battery. I figured i'd just get this cap which is a hybrid thing that apparently works partly as a battery with more storage than a normal cap and it would mostly solve the problem untill i had enough for the alt and battery. i got the cap for about $180 which is a lot cheaper than the $400ish it was looking otherwise.

It wouldn't hurt to just use the cap for now and then later when i got some more cash if i still get headlight dim i could just leave the cap in but add the new alt and battery, or is the battery something i should even be taking into consideration? My cars an 07 so the battery's pretty new.

also i didnt know that you would connect the ground on the amp to the one on the cap and then to some metal, definetly thought you kept them seperate but it probably doesnt matter
 

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If the battery's new, I would think that it should be ok, right? Maybe I shouldn't be making that assumption. I don't know.

If you already bought the cap, then I guess it's all a non-issue. Install it, and see if it takes care of whatever problems you were experiencing before.
 

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Get an alternator. Having the cap will help, but not until you can supply it the power it needs...
 

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do you currently(sorry bad pun) have a problem? lights dimming? car stalling? dome light fading?

NO... A cap is no different than another battery, a pair of fog lights, a set of neon tubes or a cobra-snake shift knob with glowing eyes... its a LOAD on the alternator.. period.

your vehicle electrical system is designed so that the alternator provides enough charge to RUN the car AND recharge the battery after starting. the battery's ONLY function is to store enough energy to START the car. PERIOD. end of discussion. Beyond the concept that electrons flow neg to pos, this is the single most misunderstood concept in vehicle electronics: the battery is only there as a storage device to START the car.. nothing else. If you have to pull from the battery to support additional loads, you are exceeding the alternator's capacity. FAIL!

What are the fuse ratings on the 1200w :rolleyes: & 4ch amp? take that & look at the 2.5i stock alternator rating.. the stock alt has just enough to support the car... upgraded alt's are available all over for Subbie's... even my crashed one.. lol..

upgrade the alt & the supporting wiring first (yes including grounds). main battery second. if you still have an actual problem.. then look for options which do NOT include caps.....

Rob
 

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<bow> (turn left) <bow>

thank you... thank you very mush...

Rob
 

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Rob, have you ever pulled the battery out of your running vehicle and then cranked the tunes? Well, first of all, don't do it. ;) But, if you...let's say...accidentally do it, I think you'll reverse a few things that you say above.

What will often happen is that the amp shuts off.

How can this be, if everything is running off the alternator? Well, the battery does help out a little. During extended transient demands, it can actually supplement the current delivery. If you monitor the electrical system's voltage on an o-scope, you'll see why. The voltage can periodically dip at times, coinciding with peak current draw. When it would otherwise get below the battery's nominal voltage (usually around ~12.5v or even higher), the battery supplies some current along with the alternator.

This is one reason why the battery is so incredibly important. The other reason is because a healthy battery is generally going to draw less current while charging than an unhealthy one. It will act as less of a load, so to speak.

As for the cap issue, like I mentioned in my other post, when the amp is at full bore, drawing a massive amount of current from the alternator/battery... and the cap is discharging into the amp... the cap is NOT drawing any current from the electrical system. It's doing the opposite. It's delivering current TO the electrical system (by way of the amp). The cap only charges when the electrical system rebounds -- ie. when the electrical system's voltage begins to go back up. But this isn't the problem, right? The problem all of us in the car audio world are trying to deal with is our big ass amps sucking all this current. We don't really care what happens when the amps AREN'T drawing so much current. But that's precisely when the cap looks like a load to the electrical system.

Long story short... it's only a load during downtimes. During musical transients, it's an anti-load. :)

Edit: One other way of looking at it.. We have a name for a circuit where a capacitor is in parallel with a load. It's called a low-pass filter. The only difference between it and the low-pass filter we use on speakers is that there's no series inductor.

[The only reason we use the inductor in the passive crossover is so that the amp isn't seeing a dead short at high frequencies. Preamp level crossovers tend not to use inductors.]

So, when you use a capacitor, you're introducing a low pass filter into the circuit. This is going to smooth these transient draws. If the transients are fast, and the cap is big enough (and its ESL is low enough), it can completely eliminate the transient draw from being seen by the alternator/battery -- much like a low-pass filter eliminates high frequencies in a speaker circuit. The alternator and battery would just chug along seeing the average current draw from the downstream circuit, not caring about peak draws or anything like that.
 

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From my first car (which Is till have,'75 mustang II) to my currently crunched WRX, I can disconnect the battery & my car will run fine (as designed) & the system will play just fine. Since I have properly planned the amperage draw to meet the demands. I know the current draw the CAR needs & I off-set it with the system needs. Simple really.

Amp won't shut off if the alternator is up to the task.. I don't want to depend on a battery to provide my current needs.. or future needs either.. (another pun!)

Hell my 2002 F150 had nearly 150 amps of "peak" fused amplifier power that I never once tapped with the factory 130amp alternator.. go figure.. its about the application.

Caps are a band-aid & marketing joke. Low ESR is critical, no denying that, caps can enhance a properly laid out power system. they won't solve anything.

the whole "only a drain sometimes "is just marketing hype to sell caps.

If anyone has access to the original Autosound2000 white papers on ESR/Cap design & cap theory... please link them up....

Caps are a joke.. If you are going to spend $$ on caps.. Go HUGE or go for a beer.. if you choose to put another load on your electrical system be sure it has enough capacity to store lots of power in the interim.. its a waste.. but hey... its there..

the fact is there are sooooo many short cuts taken in the stock automotive electrical systems, by all companies, that upgrades in wiring, alternators, grounds, & simply solid connections will yield more gains than any cap...

I won't get into a pissing match. Do the research... test you own car.. upgrading power & ground wires makes a HUGE difference in the entire vehicle's performance. its E-L-E-C-T-R-N-O-N-I-C fuel injection. its electrical flow. remove the bottle neck, improve the final outcome..

I've been down the road of the "big 3" doesn't matter (it does) & fought that battle. I've been down the road that caps are important (they aren't).. whatever..

Spend your $$ how you see fit.. you can't argue real world applications..

Rob
 

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follow up... if traditional cap design is so realistic... why did Richard Clark & David Navone have to create an "active cap" system to defeat the inherent issue with the electrical system?

Please read this next part carefully: In a REAL WORLD, daily driven car caps are a hindrance not a help. In an SPL vehicle, designed to only produce a single note to get a score, they were outlawed.. everyday cars with even the most elaborate systems do not need caps. The owners are SOLD caps to offset system design flaws.

Rob
 

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Well, you're certainly entitled to your opinion. And I agree with a lot of what you say. People who sell caps for a living overstate their case. I don't believe that caps are terribly important, or that they even have a place in most vehicles! But I do think there are certain situations (dimming headlights, specifically) where they can be a cheap and easy solution. I say "cheap" because you can buy a 1F cap on ebay for peanuts. Unless you insist on having the latest blow-me features and the big name on the side. :)

But the part I think you're not being accurate about is this whole "load" business. There are no deleterious effects of adding capacitance to the circuit. As I've explained, it doesn't behave as a load. I didn't get that from a marketing department. In fact, I don't think marketing departments even SAY that. It's really a non-debatable point. It's ohm's law + joule's law of heating. A cap does not dissipate power (if we neglect the negligible current flow through the ESR, which I think if you run the numbers you'll see is a reasonable assumption).

BTW, regarding the battery issue, you should check out what ray had to say in the linear power thread about that issue. It's worth the read.
 
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