im trying to build around a 2 fared capacitor out of numerous small ones. could someone give me a direction on what kind and how many would be best? im trying to have it around 1-1.5" tall thats the only thing that matters.
One has to ask why, when power caps are actually not good for your system. All they do is put strain on the alternator.
Basically you will need to find some capacitors that meet your size requirements, rated at 16 volts or above. Then you will need to purchase 2 million microfarads worth of them. If you use 4700 mic caps, you will need 425 of them. Using 10,000 mic caps you will need 200. Using 50,000 mic caps would require 40 of those.
Sure, paralleling 72 of these 27,000uF 25V capacitors will give you 1.944 Farads.
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=P6897-ND
That's $267.72 worth of capacitors with a layout of roughly 11" x 12.4" x 1.38"
Or, you could just buy a 2F cap marketed for car audio for around $20 and find somewhere else to put it.
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=P6897-ND
That's $267.72 worth of capacitors with a layout of roughly 11" x 12.4" x 1.38"
Or, you could just buy a 2F cap marketed for car audio for around $20 and find somewhere else to put it.
richie00boy said:
It all depends...It works for some and for others it might not work for them...All I know is that it's helped out my system a whole lot to have one as I haven't had any issues for the past year since I put my first one in...It's matter of choice I guess....
theAnonymous1 said:
Which serves to highlight just how much useless junk these car audio power caps are. You simply cannot make a decent cap of that capacity anything like that cheaply.
You are better off upgrading your earth wiring. "The big 3"
Try Bat-Stat Caps instead, there smallest unit is 80 farad equivalent and its a bunch cheaper then any of the electrolytic caps your looking at.
They stack these in Kinetik car battery's. They are fast charge battery's that don't normally vent or leak, and rarely if ever explode like regular electrolytic caps can... Remember to fuse the connections such things no matter which you chose to install....🙂
They stack these in Kinetik car battery's. They are fast charge battery's that don't normally vent or leak, and rarely if ever explode like regular electrolytic caps can... Remember to fuse the connections such things no matter which you chose to install....🙂
Capacitors are a gift and the curse.Depending on the system you are designing,this will generally indicate the usefullness of a cap-bank.
#1 If you are a bass-head or part-time bass-head or a SPL Freak.
Capacitors are not for you.Just as you get a spark(if done the wrong way)from the initial charging of any cap (name brand and design doesnt matter).This spark is because the cap is depleted and electrically rendered a dead short.And now needs a ton of current to charged.The more capacitance 1,2,3,4,5,6,,7,8,9,10 Farrads the more charge to replinish once stored charged is deplinished.And this can continue as your playing your stereo.If the audio demand on the amplifiers calls for extra current guess where it comes from the caps first.If the demand depletes them they are recharged at some what the same rate.And all this occurs in real-time,no sparks just huge loads of current being transferred from battery(and alternator if car is running)to capacitor to amplifier to what-ever speakers. Now thats a mental Transducer
And so large low freq.notes played for extended periods (short crest factor)Renders caps almost useless.And even a hinderance if your into the spl thing.Because the flow of current is now hindered from reaching the amplifiers because of caps trying to recharge themselves to a state of replentishment.
#2 If your a general audiofile or part-time audiofile or you just like your stereo easy like sunday mornings.Then cap might be a option for you.Car audio amps operate by pulsing power from the source ie. battery or Alternator if car is running.This can be problematic at times.And since no one here has fiqured out the Class A debate.PWM is what were stuck with.This pulling of power is in direct proportion with the audio signal.It is how well your electrical system can manage this tug-of-war that will prove or disprove the use of caps.
As long as your listening to music with sensible crest factors and you are not exceeding certain factors.Capacitors will add a certain sense of headroom operation for the ampifiers.Since theres no current-voltage drop.Transferr of Pulsed current has now better regulation(for lack of a better term).
#3 Just be honest with yourself.If you are a in the closet bass-head wanna-be.Only sometimes with my friends,weekends,Forth of July,Cinco De Mayo,Octoberfest,Final Exams,whenever there are fireworks and barbeque,or on Baby Jesus birthday then you need to concentrate on up-grading your cars electrically power-supply not caps.Capacitors don't generate power
#1 If you are a bass-head or part-time bass-head or a SPL Freak.
Capacitors are not for you.Just as you get a spark(if done the wrong way)from the initial charging of any cap (name brand and design doesnt matter).This spark is because the cap is depleted and electrically rendered a dead short.And now needs a ton of current to charged.The more capacitance 1,2,3,4,5,6,,7,8,9,10 Farrads the more charge to replinish once stored charged is deplinished.And this can continue as your playing your stereo.If the audio demand on the amplifiers calls for extra current guess where it comes from the caps first.If the demand depletes them they are recharged at some what the same rate.And all this occurs in real-time,no sparks just huge loads of current being transferred from battery(and alternator if car is running)to capacitor to amplifier to what-ever speakers. Now thats a mental Transducer
And so large low freq.notes played for extended periods (short crest factor)Renders caps almost useless.And even a hinderance if your into the spl thing.Because the flow of current is now hindered from reaching the amplifiers because of caps trying to recharge themselves to a state of replentishment.
#2 If your a general audiofile or part-time audiofile or you just like your stereo easy like sunday mornings.Then cap might be a option for you.Car audio amps operate by pulsing power from the source ie. battery or Alternator if car is running.This can be problematic at times.And since no one here has fiqured out the Class A debate.PWM is what were stuck with.This pulling of power is in direct proportion with the audio signal.It is how well your electrical system can manage this tug-of-war that will prove or disprove the use of caps.
As long as your listening to music with sensible crest factors and you are not exceeding certain factors.Capacitors will add a certain sense of headroom operation for the ampifiers.Since theres no current-voltage drop.Transferr of Pulsed current has now better regulation(for lack of a better term).
#3 Just be honest with yourself.If you are a in the closet bass-head wanna-be.Only sometimes with my friends,weekends,Forth of July,Cinco De Mayo,Octoberfest,Final Exams,whenever there are fireworks and barbeque,or on Baby Jesus birthday then you need to concentrate on up-grading your cars electrically power-supply not caps.Capacitors don't generate power
i just had the idea to aid in the quick spikes of voltage. as i have read now if i do get one ill just buy one and not waste my time trying to build one. thanks for the different opinions.
Amc32 about covers what I have found. Some say it is better to add caps to the rails in the amp, yet others say a good amp will have enough. I bought a used 1f for $15 shipped, I still never mounted it even after I found some copper pipe clamps that should work. I listen to lots of different music, I like low bass but not pure basshead music so I figured it might help a little. Beyond that I was thinking a jumper pack or just the battery out of it may help more....especially since I have one sitting here and it is small and sealed, and I don't plan on alternator mods or additional car batteries.
I should add I was putting the cap in more to help my alternator live than help the amps.
I should add I was putting the cap in more to help my alternator live than help the amps.
Amplifiers act as frequency doublers when it comes to draw current from the 12V system. A 40Hz tone will draw most of the current in the form of 80Hz pulses from the 12V system. It's quite important to remember this rule.
The AC impedance of a capacitor is:
Z=1/(2*pi*F*C)
Thus, for 2 farads and a 40Hz tone we get:
Z=1/(2*3.1415*80*2)= 0.001 ohm
The impedance drops proportionally as frequency increases, so for 2 farads and a 80Hz tone Z is 0.0005 ohms. This outperforms almost any battery, particularly when wiring resistance is added to the equation. The best batteries are in the .002 to .003 ohms range.
Then it comes capacitor ESR (equivalent series resistance), which appears in series with Z and determines the actual voltage drop. ESR is a direct indicator of capacitor quality and anything above .001 ohms becomes progressively useless.
The advantage of paralleling many small capacitors is a very low total ESR. In the previous example of 72 pieces of 27000uF 25V, which actually cost $186 (including quantity discount), ESR is 0.025/72=.00035 ohms which is a very good figure and outperforms almost any commercial car audio capacitor. The ESR of electrolytic capacitors may drop by 50% or more when temperature is increased, so they may perform considerably better at 50ºC than at 10ºC.
A capacitor does not increase the stress put on the alternator and the battery. It does not increase system current consumption either, it just shifts the current consumption frequency spectrum towards DC, and it makes the peak to average ratio closer to 1, which actually reduces the stress put on the whole electrical system.
In any system intended to play loud, a capacitor is always advantageous provided that it has low ESR and is placed very close to the LF amplifiers. Wiring resistance will obviously add to ESR. A system having a single standard car battery, long power wire runs, and amplifiers with little internal capacitance is likely to benefit most from a capacitor.
BTW: The results of any analysis on that subject not performed in terms of resistance, impedance, volts and amperes are usually wrong and of little use (not to mention laughable).
The AC impedance of a capacitor is:
Z=1/(2*pi*F*C)
Thus, for 2 farads and a 40Hz tone we get:
Z=1/(2*3.1415*80*2)= 0.001 ohm
The impedance drops proportionally as frequency increases, so for 2 farads and a 80Hz tone Z is 0.0005 ohms. This outperforms almost any battery, particularly when wiring resistance is added to the equation. The best batteries are in the .002 to .003 ohms range.
Then it comes capacitor ESR (equivalent series resistance), which appears in series with Z and determines the actual voltage drop. ESR is a direct indicator of capacitor quality and anything above .001 ohms becomes progressively useless.
The advantage of paralleling many small capacitors is a very low total ESR. In the previous example of 72 pieces of 27000uF 25V, which actually cost $186 (including quantity discount), ESR is 0.025/72=.00035 ohms which is a very good figure and outperforms almost any commercial car audio capacitor. The ESR of electrolytic capacitors may drop by 50% or more when temperature is increased, so they may perform considerably better at 50ºC than at 10ºC.
A capacitor does not increase the stress put on the alternator and the battery. It does not increase system current consumption either, it just shifts the current consumption frequency spectrum towards DC, and it makes the peak to average ratio closer to 1, which actually reduces the stress put on the whole electrical system.
In any system intended to play loud, a capacitor is always advantageous provided that it has low ESR and is placed very close to the LF amplifiers. Wiring resistance will obviously add to ESR. A system having a single standard car battery, long power wire runs, and amplifiers with little internal capacitance is likely to benefit most from a capacitor.
BTW: The results of any analysis on that subject not performed in terms of resistance, impedance, volts and amperes are usually wrong and of little use (not to mention laughable).
It's unlikely that there will be an audible difference with either type of capacitor (especially if the amplifiers have regulated power supplies).
With capacitors, if the voltage drops because the capacitor couldn't provide the requred current to keep the voltage constant (almost always happens on long bass notes), the alternator will have to try to recharge the capacitor as well as supply current to the amplifier (which may continue to draw significant current after the cap is discharged).
That $200 could be used to have his alternator rebuilt (to produce more current) or put towards an alternator rated for higher current output. A properly designed system will have the alternator it needs to prevent significant voltage drop when listening to the system at high power.
With capacitors, if the voltage drops because the capacitor couldn't provide the requred current to keep the voltage constant (almost always happens on long bass notes), the alternator will have to try to recharge the capacitor as well as supply current to the amplifier (which may continue to draw significant current after the cap is discharged).
That $200 could be used to have his alternator rebuilt (to produce more current) or put towards an alternator rated for higher current output. A properly designed system will have the alternator it needs to prevent significant voltage drop when listening to the system at high power.
Capacitors are linear devices, unlike batteries. The capacitor together with the electrical system will always provide the required current. The sharing depends on frequency and impedances. It does not depend on the magnitude of the load current.
Alternator regulators are very slow acting devices, they may easily take 0.5s to react to a load change. With a capacitor the regulator will no longer be required to swing continuously between maximum output and minimum output following the beat.
The effect of a capacitor is to convert brief high current demands into long low current demands, which put much less stress both on the alternator and the battery. Average current draw is the same.
Batteries have a wide dead band between 12V and 14V. They won't provide serious current until the voltage has dropped to 12V and they won't take any serious charge until it has risen above 14V. This results in serious voltage ripple when audio amplifiers are used without a capacitor due to the "fast" pulsed nature of the power consumption and the slow nature of alternator regulation.
There is nothing else on the electrical system of a car capable of such an unsteady current consumption pattern. The whole system is not intended to be used that way.
All the 12V supply bypass electrolytic capacitors found in every piece of electronics connected to the 12V line will be stressed by this 12V-14V ripple, including the own car electronics.
The advantage is electrical, not sound related. Sound is not likely to change at all, but lights won't dim with the bass, and the small 12V bypass capacitors found on the DVD player, the head unit, the ignition system or the own amplifiers, won't vent or dry and lose its capacitance after some time (they "die" trying to "smooth" the ripple produced by the amplifiers). I've had to replace dozens of these capacitors.
Alternator regulators are very slow acting devices, they may easily take 0.5s to react to a load change. With a capacitor the regulator will no longer be required to swing continuously between maximum output and minimum output following the beat.
The effect of a capacitor is to convert brief high current demands into long low current demands, which put much less stress both on the alternator and the battery. Average current draw is the same.
Batteries have a wide dead band between 12V and 14V. They won't provide serious current until the voltage has dropped to 12V and they won't take any serious charge until it has risen above 14V. This results in serious voltage ripple when audio amplifiers are used without a capacitor due to the "fast" pulsed nature of the power consumption and the slow nature of alternator regulation.
There is nothing else on the electrical system of a car capable of such an unsteady current consumption pattern. The whole system is not intended to be used that way.
All the 12V supply bypass electrolytic capacitors found in every piece of electronics connected to the 12V line will be stressed by this 12V-14V ripple, including the own car electronics.
The advantage is electrical, not sound related. Sound is not likely to change at all, but lights won't dim with the bass, and the small 12V bypass capacitors found on the DVD player, the head unit, the ignition system or the own amplifiers, won't vent or dry and lose its capacitance after some time (they "die" trying to "smooth" the ripple produced by the amplifiers). I've had to replace dozens of these capacitors.
OEM alternator regs are slow. Some aftermarket alternators have faster regulators and can act virtually instantaneously.
If the alternator cannot keep up with demand, the capacitor will not stop the lights from dimming. I don't know of a single reputable shop that pushes capacitors. They will only sell them if the customer insists on buying one. Most are tired of customers complaining because the lights on their car still dim after installing the capacitor.
In 20+ years of repairing car audio equipment, I've never seen a single failed capacitor across the B+/ground input in a head unit. Most head units have inductors that won't allow excessive ripple to get to the filter capacitors. The low frequency that does get to the cap isn't harmful.
Across the pond, things may be different. The batteries are typically smaller and probably can't filter ripple as well as larger batteries. There may be other differences.
If the cap won't stop the lights from dimming (not possible on long bass notes if the alternator can't keep up), won't make it sound better and he isn't having a problem blowing filter capacitors in his head unit, there's really not much point in spending $200 on a capacitor.
If the alternator cannot keep up with demand, the capacitor will not stop the lights from dimming. I don't know of a single reputable shop that pushes capacitors. They will only sell them if the customer insists on buying one. Most are tired of customers complaining because the lights on their car still dim after installing the capacitor.
In 20+ years of repairing car audio equipment, I've never seen a single failed capacitor across the B+/ground input in a head unit. Most head units have inductors that won't allow excessive ripple to get to the filter capacitors. The low frequency that does get to the cap isn't harmful.
Across the pond, things may be different. The batteries are typically smaller and probably can't filter ripple as well as larger batteries. There may be other differences.
If the cap won't stop the lights from dimming (not possible on long bass notes if the alternator can't keep up), won't make it sound better and he isn't having a problem blowing filter capacitors in his head unit, there's really not much point in spending $200 on a capacitor.
Ok time to take off the gloves! Just kidding! (Eva)you come off as a Telsa disciple.I think I speak for everyone when I say we appreciate the Farraday white pages.But car stereo doesnt have to be so techincal to sound good.Look at something for a second{the tread was started by someone named AUDIOBAHNKID}I believe Perry and myself are saying the same thing you are saying,just in more basic terms.These kids only become more confused when they hear so-called experts differ in the minute aspects of an issue.And maybe you might find my initial response comical but it still stands true.I didnt include ESR,induced inductance,current leading voltage aspect because for the inquiring its a no brainer when he or she looked at the cost.
Dont take any of this the wrong way I still need your help on other things.But I just wanted to clear the testosterone,before the fangs and venom were drawn.
And that's my manditory minimum!
Dont take any of this the wrong way I still need your help on other things.But I just wanted to clear the testosterone,before the fangs and venom were drawn.
And that's my manditory minimum!
As far as sound to capacitors are concerned.As I stated earlier"with the proper electrical system caps can provide a persive headroom"this headroom can be heard and also measured(electrical).Yes car amps use PWM powersupplies and it power consumtion is in direct proportion to its audio output( not its sound quality,loosely stated)If someone dedicated themselves to class A audio amplifiers for the car then the debate over Capacitors would be mute.Because its Power comsuption would act also in a Class A fashion.With a fixed freq. and Impedance.Much like the lights in your home either you have the power or you dont.Only in the realm of car audio,can someone actually be some what pregnat.
Who hasn't been an "audiobankid" at some point in life? Ten years ago I was one too. But thanks to internet I started to read scientific explanations of things and to do my own experiments and my mind gradually changed. In the process I learned to do stuff like that (just an example related to car-audio): http://www.diyaudio.com/forums/showthread.php?s=&threadid=111566 Now I specialize in switching mode power electronics, class-D and high efficiency loudspeakers.
The beauty of forums is that everything that you write remains in the database, no matter if the original poster was not interested in your reply because it was too technical. If you write accurate explanations, they may be useful later for anybody else really willing to learn about the subject. The good explanations are still being read by many people months or years after they have been written. Then again, at some point it's unavoidable to become deeply technical when it comes to get the best out of sound systems.
The beauty of forums is that everything that you write remains in the database, no matter if the original poster was not interested in your reply because it was too technical. If you write accurate explanations, they may be useful later for anybody else really willing to learn about the subject. The good explanations are still being read by many people months or years after they have been written. Then again, at some point it's unavoidable to become deeply technical when it comes to get the best out of sound systems.
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