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Thats a good question but I will explain one more time why they don't work. You don't have the power to run your amp(s) and you add a cap. One bass note will drain the cap and then the next bass note you alternator is tring to power your amp and recharge your cap so, your putting way more strain on your alternator. It is a fact that a capacitor cannot add power. The only source of power is the alternator.

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Nik
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there are many posts here where people have ranted about the uselessness of caps for 5+ pages.

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Nik
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well, I have always heard that you should have a 1 farad capacitor for every 1000 watts of power regardless of your alternator output. Because, a capacitor can react faster than your alternator can, and can recharge between bass hits, so that if a little extra power is needed then it wont get that power from your battery it will just get it from the capacitor.

You can add as many caps as you want but its a simple fact that they will do nothing. A cap takes 3-4 times longer to charge than to discharge. And will increase strain on your alternator. I too have heard of adding 1 farad per 1000 watts but that comes the makers of caps. If you add a cap now chances are you will end up adding an alternator anyway.

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Nik
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Because, a capacitor can react faster than your alternator can, and can recharge between bass hits, so that if a little extra power is needed then it wont get that power from your battery it will just get it from the capacitor.
That is the jist of it. Problem is, a lot of guys are trying to fix a power problem by using a cap....or are rookies in this car audio world and buy what their friends or salesmen tell them they should. If you are not having any problems, and would like to add a cap, go for it. But if there is an issue with your system that needs fixed, let's look at that and fix it.
BTW, it was a salesman who came up with the 1 farad per 1000 watts rule. Who else? Gotta have some guidelines, don'tcha?
Oh yeah, your question. You can park another one right next door to the original if you want to, but don't go nuts and keep adding caps. Don't even add the second one, in fact, until you find out why you think you need a second one.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

Basicaly if you don't have a problem, no need for a cap. And if you do have a problem, a cap won't fix it. Sorry for my ranting but I just hate the fact that these multi million dollar companies make up bold faced lies to steal some 16 years old birthday money.

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Nik
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I think caps do indeed have a purpose. but everyone tries to use them to fix their lights dimming or use it to avoid buying a larger altenator. Simple fact is that if I am using my daily driver and are not experiencing any problems with my charging system at the levels I listen to my music then great, but if I also use that same car to compete with and the charging system cannot handle the strain of those big ass 50 hz hits, then a cap might very well help being I am only gonna run for 30 seconds and only need a couple burst durring that time. Its a shame that every second kid thinks they need a cap to put in their 94 cav because the lights blink, but thats word of mouth and thats marketing, plain and simple. As to the original question, you can add as many caps as you want to a system and they can be whatever sizes you want. I think you would be best off to post why you feel you need a cap first so we can figure out if its the best chicken soup for your soul

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double-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer

Five years ago I helped build a 20,000 watt system in a Suburban for a radio station. No caps. None needed (six 300-amp alternators and six batteries. Oh, and an onboard 120V power supply and outboard generator as a backup.)

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Mabye Ill just do that on my next system, that sounds way easier posted_image

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double-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer

OK, don't read the next sentence and judge me before reading the whole post, that should go without saying but I've had people do that before. Basically I am trying to avoid buying a bigger alternator, but hear me out first. I have not installed my system yet and therefore do not know if I will have a problem. I have a 2002 Chrysler PT Cruiser and I want to add a power hx2 sub from Rockford Fosgate which is 1000 watts RMS. I was planning on getting an Audiobahn a1300hct which can run at 1200 watts RMS x 1 at 1 ohm. What I have been told is basically if I am borderline and almost in need of a bigger alternator then a capacitor would help keep me farther towards the safe side. I hope that I wrote that where it makes as much sense as it does in my head.

A properly used stiffening capacitor can help an amplifier sustain peak output during short music transients. It is designed to help the amplifier's power supply maintain peak rail voltage. It helps in vehicles where the max current draw of the system is at or close to the max capcity of the alternator, since a cap can discharge more quickly than an alternator can supply current.

Assuming your amplifier can actually produce 1200 watts (which is another topic altogether) it will require around 175 amps from your electrical system when it peaks. The continuous draw of that size amplifier would be about 60 amps. This means you need to rate your power cable and fuse for the peak (175 amps) and your alternator will be required to produce ~60 amps continuously over what the vehicle normally requires to run. Since most car alternators have about a 40% reserve capacity (meaning the normal vehicle loads use up about 60% of the alternator's total capacity and you have 40% left for peaks and add-ons) you will need an alternator rated at around 140 amps. THEN a cap can help supply the 175 amp peak and help the amplifier sustain its output and keep your lights from dimming during transient peaks. But only after the alternator is already big enough.

I doubt the OEM alternator in a PT Cruiser is rated at 140 amps. I doubt you are "at the edge." I suspect you are way over it.

This, my friend, is the down-side and hidden cost for wanting to run such a large amplifier.

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I believe the OEM alternator is 110 amps.

Can you tell me what the maximum wattage a 200 amp alternator could handle with a 5 farad capacitor?

it all depends on the amplifier

My amplifier draws a max of 60 amps (since it has 2 30-amp fuses on it :) ). Look at the fuses on the amplifier (if it has any), and know that it won't draw over that many amps....

The cap won't let you run a bigger amp. I have a cap, and it does help, but what it does is keeps my amplifier at about 13.7 volts during hard hits (and I'm not talking about 50Hz hits, I'm talking about 20 or so Hz hits....lol)

I dont know if that was a shot at me but just in case it was, I understand that 50 hz is not a low hit and is no where near the hardest frequency to reproduce in a car, just that serious spl systems, esspecially one not wonders tend to be in the 50-65 hz range. Just clearing myself up here

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double-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer

Edicius: Why are you interested in a second rate solution that probably won't even work for a small difference in money?

Buy an alternator or go with less wattage. I think a capacitor would be a complete waste of money for you.

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New Project: 2003 Pathfinder

Well, I would say that the moderator on this site with almost three times as many posts as you would be a "decent reference". In my opinion.

First, DYohn basically said they're worthless in all but the closest cases and ONLY AFTER the alternator is large.

Second, I still want to see some proof. Why do none of these capacitor manufacturers list any concrete data behind what their products do? I want to see a graph that shows me how they fill in these dips in current. Why don't they show us this? You'd think it would help them sell. This lack of data is because they don't have it.

In the end, buy the cap, makes no difference to me if you don't buy the best solution. Heck, I hear caps still get "street cred" among the uninformed - right up there with chrome flame decorations on the subwoofer.

To me: I see a cap and I say, "9/10 chances that guy doesn't need that and was suckered by the salesman."

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New Project: 2003 Pathfinder

You sure seem angry for someone who doesn't care.

Oh, I'm not angry, I just like to argue my point until someone comes back with a quality rebuttal. I do it all the time. Sometimes I do lace on the sarcasm a bit hard - I'm sorry for that.

I also find it unfortunate that so many people waste their money on products that do relatively nothing. So, in a sense, yes, I am slightly annoyed at the manufacturers for selling their misinformation.

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New Project: 2003 Pathfinder

ya... i agree wit u all. the cap only keep the current from the battery and then the power will push out 4 the amplifier. when the current are empty in the cap, the cap will recharge back from battery. this are also the same. maybe the caps can supply more current and high ampere to your amp just 4 a while not 4 a long time.

4 my experient, in ICE world, the caps are not missing from the wiring in the car. if they use 10 amps, they also use 10 caps. i think the caps only nice to see but it nothings. maybe its beautiful when we can see the digit come out from the cap. he he he.

me also want to buy this caps long time ago, but my friend told me to get a big alternator with the big calcium battery where it can supply more current and more ampere 4 the amps.

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RICK ENGINEERING

Edicius wrote:

Well, I would say that the moderator on this site with almost three times as many posts as you would be a "decent reference". In my opinion.

Whoa, if you got the opinion from my post that caps are a good solution for you, then I must not have written it very well. Let me try to be clear:

Capacitors are a waste of money for most people. Amplifiers do not need external capacitors. A capacitor is not a power source since it must be charged from somewhere. If the charging system is already overloaded, a capacitor will makke things worse, not better; larger capacitors create larger problems in this case. A capacitor can sometimes be used to assist the power supply of an amplifier to maintain peak power but only if sufficient volts and amps are already available from the alternator/battery. The person who told you your system will be fixed by adding a capacitor was wrong. High capacity alternators and matching high capactiry batteries are the only way to provide power needed by a large amplifier. To figure the end cost of installing a high-wattage amplifier you must include the additional costs of a HO alternator, appropriate wiring, etc.

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I'm in no way an expert on this subject, but in my case the 1 farad cap definatly helped with the lights dimming when the bass hit hard. now that I'm thinking about up grading my amp to 2-3 times (1000-1500 wrms) the output that i have right now, i will be back at square one and will probably need the HO alt.

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All Bleeding stops.....eventually!

If you're putting a pansy system in, you might not need crap. (Its pansy if it is like under 300wRMS, as far as I'm concerned.) My friend has some pioneer stuff setup in her car(sigh) and she didn't put anything else in it as far as I know other than amp+subs. It doesn't hit worth much to me, but it works for her and she needed nothin. Now for my system I need an improvement(1300wRMS). My options are:

1) HO Alternator, costs me $200 for 180 amp and some money for cable and shipping. $242 all together.

2) Try and cap it for like $150+ for the appropriate capacitor... *looks* You gotta be f'in kiddin!!!! (This is assuming it'd work and not put so much work on my alternator it dies like in a week and I have to not only buy a new alternator, but one that won't die, so now I'm out on the cap entirely because I was DUMB.)

Now given my car is unique, since no one ever wants to screw with this kinda car due to it being old person car and the special mounted alternator limits it to a max of 180a. But still, I'd rather spend 2x more on something that not only solves a problem BUT it improves the functionality of my car.

Sorry, I just wish I had the money to blow, really.

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1998 Monte Carlo w/
Eclipse CD8454
2xRockford 5.25" Power 2-way T152C
2xRockford 6"x9" Punch 3-way FRC4369
1xMemphis 16-MCH1300 5-channel
2xKicker 12" L5 Solobaric-2 Ohm

"Whoa, if you got the
opinion from my post that caps are a good solution for you,
then I must not have written it very well."

NO, I was saying that what you said was the real purpose of capacitors and therefore was a "decent reference" for them. Not that they would replace a high output alternator. Which is what I'm going to get.

Well I'm glad you finally got the point

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Nik
Jeeputer Progress
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well, that's what i was originally going to do, i just like to make extra sure before i do things so that i don't waste my money. if an alternator was unnecessary, then i could spend that $460.00 somewhere else.

caps do help, they wont solve major problems, if you are going to buy multiple caps there are cap blocks that have 30 -50 farads for a few hundred bucks, like 300 or so, which if you buy regular priced caps at about 75 bucks a farad, that makes a lot more sence, the alternator is definetly the way to go, but if your alt is keeping up fine, then a cap will help a little, but it really wont be THAT noticeable, they do help, but it's not going to be like a 4 db difference, and honestly most people can't really tell much of a difference with only 1 or 2 farads, so i'd worry more about the alternator and battery setup before caps, and also, think about your power wire, i don't know what you are running, but there is a huge difference in running a good 1/0 gauge versus a litle 8 ga. wire, depending on your system size you might not need to go crazy like 0, but a 4 or 2 is a good choice if your doing anything over a good 1000 watt amp, just my $ .02

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Bad Boys Customs
audio - video - security

If you use it. Suport it. Donate to the 12 volt!

and i run an audio store, the one thing i have customers bitching about all the time is this "why don't you stock any capacitors",, really? because there are about 5 things that should be on your list before caps, and most people don't even get to number 3 unless they are DEAD serious about stereo's, i have put a few HO alternators in cars, and it really does help a lot, even just a little extra 40 amps or 50 amps will make the world of a difference, caps would help for competitions, for that one quick burp, but after that,, you have two things draining on that alt, the cap AND the amp. sorry about going on and on like that, so really, the uses for capacitors, a volt meter, some pretty crome sh*t to have back there, and more flashy lights, +10 points to your "fast and furious"ness, really doesn't do much for the audio tho,

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Bad Boys Customs
audio - video - security

If you use it. Suport it. Donate to the 12 volt!

Hey captanham, how 'bout some SENTENCES?!?! What the HELL were you trying to say? I can't make heads or tails of it! If you want to help, then do so, but please use some proper grammar and punctuation.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."