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i need a cap

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=131147
Printed Date: December 02, 2022 at 5:39 PM


Topic: i need a cap

Posted By: mdlwate357
Subject: i need a cap
Date Posted: April 08, 2012 at 9:12 PM

Never used a capacitor before, but my new system find the headlights everyone the bass hits. After looking on ebay I see mostly low end brand caps....planet audio, , boss, power acoustic, bulls, ect... I only need a 1 farad cap, but I wanna keep it under $ 100. I'm running a JL 500/1 slash and a pioneer premier 400 w 4chat. I have a Pioneer Premier head unit, kicker kq5 equalizer all running a 10 w7, mn quart premium 6.5 components and two boston acoustics 4x6 dash speakers......all crammed in a regular cab s10. So what I'm asking is for recommendations of a good cap in my price range and is there anything I need to know since I've never ran one before?



Replies:

Posted By: i am an idiot
Date Posted: April 08, 2012 at 9:38 PM

Do not waste your money on a capacitor. 





Posted By: mdlwate357
Date Posted: April 08, 2012 at 10:15 PM
Is there another solution to my headlights strobing to the beat while driving down down the road ????




Posted By: mdlwate357
Date Posted: April 08, 2012 at 10:18 PM
Sorry about the first post... I have a new phone and haven't yet disabled the auto-fill feature so it changes my words sometimes and I dont always think to check. I meant that my headlights dim everytime the bass hits.




Posted By: KPierson
Date Posted: April 09, 2012 at 6:44 AM
Yes - fix the problem. Headlights dim when the voltage drops. Voltage drops when too much current is being pulled from the battery. Put more current in to the battery (bigger alternator) or increase the efficiency of the current battery (the big 3) or at a bare minimum put in a better battery.

A cap doesn't create extra current and won't fix your problem. This is why only cheap ones can be found - if they worked everyone would sell them!

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Kevin Pierson




Posted By: mdlwate357
Date Posted: April 09, 2012 at 1:46 PM
No disrespect, but a 1 farad rockford fosgate cap complety fixed the problem. I had just put in a new battery and alternator 6 weeks ago. Together they ran me about $ 32. I just wasn't willing to not only waste that $ 320, but go spend another $ 350 or so on another battery and alternator.....instead I took a chance on a 1 farad fosgate cap for $ 100 and honestly it % 100 fixed the problem. Last might I road with headlights, emergency flashers, windshield wipers and AC all going together and there was ZERO dimming of the headlights.




Posted By: KPierson
Date Posted: April 09, 2012 at 2:14 PM
Give it time and you'll see the cap didn't fix anything. It can't.

For a "fun" experiment start your car and turn your stereo up to the normal listening level. Disconnect the fuse to the sub amp (while still keeping the cap inline). How long does the sub amp stay on?

The point of this exercise is to see how much actual power is stored inside a 1F cap. I think you'll find that that answer is not very much.

Once the cap has been drained of it's power it then becomes a load in parallel with your battery, thus slowing down the recharge of your battery.

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Kevin Pierson




Posted By: mdlwate357
Date Posted: April 09, 2012 at 3:32 PM
Again, I ask questions here because I know that most of you know a lot more about car audio than I do... I greatly appreciate everyone who takes the time to answer my posted questions and never want that to be misunderstood. That being said, if I had a problem and now I don't have the problem....where's the problem? I've been reading a LOT about caps over the past week and while I've heard many people make your same argument, and many refering to caps as "snake oil", I have heard just as many arguments in favor of caps. Both sides with convincing evidence. All I know is this.... I installed a cap (one that is both made by a reputable manufactuer and backed with hundreds of positive reviews) and my headlights no longer dim. I even increased the load that it was under as well as playing time and still not even the slightest hint of dimming headlights. So how can you say for certain that a cap "CAN'T'Re" work ? Obviously it can because it did. Are there majority of worthless caps that will not do a thing when added to a system flooding the market ???? Probably, yes Also, of no cap could possibly work, why are they used so frequently in competitions ? Are they good for other applications ? I have nonplus, but it worked for me and I'm happy. If my lights go back to dimming I will let everybody know and I'll eat crow, but until turnIng rattling walls, windows, setting off ever alarm in the parking lot and doing it with fully functioning headlights ! Thanks again everybody for your time




Posted By: KPierson
Date Posted: April 09, 2012 at 5:13 PM
How did you judge light dimming before installing the cap? How did you judge it after? Were all system settings exactly the same under all circumstances?

Just a heads up - RF doesn't manufacture capacitors. No car audio company does. There are only a handful of factories in the world that manufacturer capacitors. All the companies are buying their caps from the same suppliers.

A typical competition vehicle has upgraded/additional alternators with battery banks/etc.

I hope that your problem has been fixed but like I said from an engineering perspective a capacitor doesn't make sense - it simply can't hold enough current to make a noticeable difference.

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Kevin Pierson




Posted By: soundnsecurity
Date Posted: April 10, 2012 at 10:59 AM
caps are used in competitions to help keep a steady voltage supply to the amps. mostly used in sound quality competitions. anyone who uses them for spl competitions either got told something by a sales person or just has them because they look pretty.

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Posted By: tommy...
Date Posted: April 10, 2012 at 4:14 PM
Upgrading Your Charging System
This is a popular topic and many people think there are simple answers. The answers may be simple but the solutions are often very expensive. Some of the problems and solutions will be covered on this page.

Dimming Headlights:
This is the most common complaint for those who have installed high-power sound systems in their vehicles. This problem can sometimes be overcome by installing an alternator rated for higher current but this isn't always the case. Some alternators have a slight regulator lag and, even though the alternator can produce the required current, it doesn't react quickly enough to prevent short-term dimming. This can vary between various alternators, even if they're rated for the same current. In some instances, the owner of a vehicle will install multiple alternators. The OEM alternator will power the vehicle's electronics and charge the OEM battery. One or more alternators will power the amplifiers and charge auxiliary batteries. Since the amplifiers aren't drawing current from the OEM system, the lights cannot dim.

If you replace incandescent headlamps (standard and halogen headlamps) with HID headlamps, the headlamps won't likely dim. HID lamps have a ballast that acts like a regulator. This regulator will keep the voltage/current constant and will therefore prevent dimming.

In some instances, you may be able to use a voltage regulator for incandescent headlamps. This is safer if you only do it for the low beams OR the high beams. This will prevent the loss of light if the regulator fails. A regulator like the Accuvolt can keep the voltage constant. In the near future, LED headlamps will be available. These will be easier to regulate because LEDs don't need the full voltage of the charging system.

Alternators:
As was stated on the charging system basics page, the alternator supplies all of the power to all of the electrical accessories (amplifiers, lights, power windows, power seats...) as long as the engine is running (unless the current demand exceeds the capacity of the alternator).

Many people want to know when they should replace their alternator. The short answer is... when it fails. If you just want the battery to remain charged and your present alternator is keeping it charged, it's doing its job. If you want a system to be as close to perfect as possible and money is no object, replace your alternator when you install the amplifiers.

Multiple alternators was previously mentioned. It's very difficult to install multiple alternators on many of the newer cars because there simply isn't any available space. For older vehicles and trucks, there are more options. You can buy brackets for multiple alternators. THIS is one example.

Extra Batteries:
Extra batteries are great if you want to listen to your system with the engine off. While the alternator is charging, the extra batteries will only draw current which could otherwise be going to your amplifiers. For proof, all you have to do is measure the voltage while the engine is running. It should be approximately 13.5-14.4 volts DC. Then turn the engine off and measure the battery voltage again. Now it'll be around 12-12.5 volts. Whenever the voltage at the battery is near 14 volts, there is current flowing into the battery. The only time that the battery supplies current with the engine running is when the current capacity of the alternator has been exceeded. When that happens and the batteries are the source of power, the voltage supplied by the batteries will be significantly less than the voltage of an alternator that's capable of supplying the required current.

One Farad (and larger) Capacitors:
Large, one Farad, capacitors only help to maintain the charging voltage for a tiny fraction of a second under high current demand situations. They won't really solve your current supply problems if your alternator can't keep up.

NOTE:
Capacitors DO NOT increase the charging system's voltage.

( Borrowed from BCAE1.com...Somehow i missed some posts)...LOL


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M.E.C.P & First-Class
Go slow and drink lots of water...Procrastinators' Unite...Tomorrow!




Posted By: oldspark
Date Posted: April 11, 2012 at 8:42 PM
Good overview Tommy. (With thanks to BCAE.)


To paraphrase or qualify various cap claims...

Caps reduce systems voltage as much as they increase it.

Caps REDUCE the strain on systems (ie, alternators) as do - in most cases - added or bigger batteries.

A small battery will outperform a cap (in the majority of cases) - ie, a$10 1.2AH will crap on a $100 or 1F or 40F cap etc. ("Aux" or 2nd battery consideration apply.)

Many DISCONNECT caps for SPL comps (they can reduce peak SPL, ie, reduce the peak voltage available).

Caps are only used to preserve AGM battery life (excessive current) on big systems (eg, 3kW with only 1 maybe 2 AGMs).

To prevent lamp dimming, caps should be at the lamp end, not the amp. A battery would do better, but its isolation switching may be the detractor.

I'm sure I've missed a few more points. And I haven't mentioned the big-3 etc nor alternator sizing.


Geez - the things I miss out on just because I'm gone a few days! (LOL)




Posted By: still_walkin
Date Posted: April 23, 2012 at 5:02 AM
heres another way to show you caps dont work just a voltometer on the battery numbers dont lie. i been on this forum for a while andd guys never stood me wrong at one point i didnt listen to them and sure as a being out in the desert with a horse with no name my car left me stranded .... because i  didnt listen when they told me your charging system is VERy important long story short HO alt bigger battery and the big three... cant go wrong.

-------------
1993 sdv
Alpine 4x6 6x9 5 1/4 swr-10d4
alpine v60
12.5 VGA flip down
Nettop pc w/10" touch screen
78nova
5-re audio 5x7 ,10" sub &
Xtx-500.5
"Take the faceplate off get the jumperpack"




Posted By: oldspark
Date Posted: April 23, 2012 at 7:06 AM
Thanks - that's good to hear. (imHo of course!)

I've always maintained that the alternator is the first target. (Well, the first after the Big 3, but that can come later unless it's a borderline case.)


If the alternator isn't big enough to handle the load over a typical drive, then the battery(s) is not recharged.
Caps will not change that in any way.
Extra or bigger batteries may extend the battery reserve time, but they will need just as much power to recharge.
And discharged batteries means sulfate build up and premature failure (more discharges & to a greater depth).


If the alternator is big enough to handle the average load (ie, enough to recharge with amps and lights etc off) but not big enough to handle the BIG load (eg, amps), the the voltage drops from (say) 14.2V to under 12.7V (1.5V lower).
So if voltage drop is so important to audio people etc, why do they think more batteries (or caps) are a higher priority than an alternator? They can only output ~12.7V and below; alternators output up to 14.4V (their long term maximum).

It beats me! (Unless promoted by battery or cap sales people & their installers.)


My biggest amusement with caps is the their original proponent (Richard Clark; and partner) has since spent much energy trying to debunk their use.
But too late - once bullsh gets a hold, followers are reluctant to let it go. Maybe they want everyone else to make the same mistakes they did?


For those that can do the cap calculations and know about batteries, the very suggestion of using a cap is ludicrous.

As I say, their only use is to prevent damage to AGM batteries, else where a 2nd battery is undesirable and Big-3 type solutions aren't enough to prevent lamp dipping etc. (One typical solution is to power the lamp relays from the main battery instead of the alternator.)




Posted By: unplugme71
Date Posted: May 21, 2012 at 11:27 AM

Capacitors are widely used in electronic circuits for blocking DC while allowing AC to pass. It is used for smoothing the output of power supplies, stabilizing voltage, and power flow.



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'03 Acura RSX Type-S




Posted By: DYohn
Date Posted: May 21, 2012 at 1:30 PM
Gentlemen, there is no need to do wholesale cut-and-paste from BCAE or anywhere else to this forum.  If you'd like to post a link to the information, that's great, but copying violates their copyright.

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Support the12volt.com




Posted By: still_walkin
Date Posted: May 21, 2012 at 1:35 PM
Its only one way to solve this capacitor war and that's to get the same exact car but add caps to one and and add the big 3 ho alt and a bigger battery to the other run meters on them.I know which one gonna but I don't want to ruin the story.

Well the one without the cap

-------------
1993 sdv
Alpine 4x6 6x9 5 1/4 swr-10d4
alpine v60
12.5 VGA flip down
Nettop pc w/10" touch screen
78nova
5-re audio 5x7 ,10" sub &
Xtx-500.5
"Take the faceplate off get the jumperpack"




Posted By: DYohn
Date Posted: May 21, 2012 at 1:42 PM

For anyone who needs a cap, I recommend one of these:

posted_image



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Support the12volt.com




Posted By: still_walkin
Date Posted: May 21, 2012 at 1:46 PM
Don't forget those cool stickers that auto zone sells

-------------
1993 sdv
Alpine 4x6 6x9 5 1/4 swr-10d4
alpine v60
12.5 VGA flip down
Nettop pc w/10" touch screen
78nova
5-re audio 5x7 ,10" sub &
Xtx-500.5
"Take the faceplate off get the jumperpack"




Posted By: oldspark
Date Posted: May 21, 2012 at 4:23 PM
DYohn] wrote:

...there is no need to do wholesale cut-and-paste from .... or anywhere else to this forum...

LOL! posted_image posted_image




Posted By: jthomsonmain
Date Posted: June 06, 2012 at 6:34 PM
Personally, I would recommend putting a sealed lead acid battery near your amp. Wire it just like you would a cap. A battery will push more current than a Cap will all day. No matter what you do without upgrading your alternator is going to put strain on your charging system.




Posted By: still_walkin
Date Posted: June 06, 2012 at 7:25 PM
True but forget to fuse next to the battery

-------------
1993 sdv
Alpine 4x6 6x9 5 1/4 swr-10d4
alpine v60
12.5 VGA flip down
Nettop pc w/10" touch screen
78nova
5-re audio 5x7 ,10" sub &
Xtx-500.5
"Take the faceplate off get the jumperpack"




Posted By: jthomsonmain
Date Posted: June 07, 2012 at 1:04 AM
Nahh... Who needs fuses? They just keep your car from catching on fire :P




Posted By: still_walkin
Date Posted: June 07, 2012 at 1:10 AM
That's kinda the point ..... fuse within 15" of the battery

-------------
1993 sdv
Alpine 4x6 6x9 5 1/4 swr-10d4
alpine v60
12.5 VGA flip down
Nettop pc w/10" touch screen
78nova
5-re audio 5x7 ,10" sub &
Xtx-500.5
"Take the faceplate off get the jumperpack"




Posted By: oldspark
Date Posted: June 07, 2012 at 3:04 AM
And don't forget to isolate the battery when not being used....
And it's TWO fuses if it's a 2nd battery - ie, one from EACH battery.


But this is a dead thread.
The OP's lamp dipping problem was solved with a cap.
Granted, it is not known if it would have been solved with better wiring (the Big-3 etc) or by using smaller & cheaper battery in lieu of the cap, but in this instance, a cap solved the problem and it has advantages over a battery (ie - maintenance & isolation is not as important).


This was not a case of filtering for amps - it was merely for the filtering of headlight power.





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