School me on Farad Caps...

[Paul]

I see 1 Farad & 10 Farad caps...Please give me all your info on them.

[Notladstyle]

1 farad caps will power a 500 watt amplifier for about 4/5th of a second during a 10v drop in supply power.

a 10 farad cap will power the same amp for a little over a second in the same situation but will probably take too long to produce the power because of the higher esr.


Power fluctuations during transients - As an amplifier produces music, it requires a varying degree of current to drive the speaker (assumed to be a subwoofer from this pint forward). The combination of amp design, sub's coil design, impedance, and the frequency being reproduced all have a bearing on the amount of current that will be required to produce sound.

Generally, lower frequencies require more current. Also generally, the first few miliseconds of a low note require more power to overcome a negative or zero inertia (stop the sub and force it to move in the opposite direction).

This momentary extra current demand is often very large albeit very short, for low frequencies - large being two or three times the normal draw of the amp. A battery can efficiently produce very large amounts of current, but not very quickly.

This demand for extra current results in a large voltage drop at the amp's power supply while waiting for the battery to produce the extra current. If the amp's internal power supply(made up of smaller value capacitors) cannot supply the current to the amp, the voltage drops. This is where a capacitor comes in. A capacitor located in very close proximity to the amplifier will supply the massive amount of current needed to maintain the ambient voltage until the battery can supply the additional current.


Do caps stop light dimming?
No, if your voltage drops long enough for you to see your lights dimming a cap will not help. Remember, we are talking about fractions of seconds.

Do caps use more power?
Yes, since you are basically supplying power during the peak demands, that power would otherwise never be supplied hence more power in consumed.

Do caps drain your system when they recharge?
NO! a capacitor will only charge when the voltage is above that of its own value. since the battery is capable of supplying a large amount of current after a brief delay, the recharge of the capacitor is transparent. if the voltage drop is not remedied by the battery after the capacitor discharges, the capacitor WILL NOT charge or pull power from the amplifier.

[Paul]

good info...thanxs a lot..what should I get for my set up?


I have a KX600.1 on a Kicker DVC L7 12"

[Notladstyle]

good info...thanxs a lot..what should I get for my set up?


I have a KX600.1 on a Kicker DVC L7 12"

It's better to use several 1farad capacitors over a single 10 farad capacitor - The 1 farad caps will be able to discharge and recharge faster than a single 10 farad cap.

For a single 600 watt amp I doubt you would need more than one.

Keep in mind, poor wiring will make 10x the difference of a capacitor. I raised my rear voltage by .3v and vastly reduced the light dimming in my car just be soldering the tips of each power wire(including the alternator and supply wires) and soldering the O rings to the wire.

[TJElite]

First lesson...the term Farad Cap is like saying ounce glass. Farad is a unit of measurement...it is not a type of capacitor. A 10 farad cap stores 10 times the energy of a 1 farad cap.

Second lesson...skip them...they are useless (pokes dalton in eye).

Toby

[TJElite]

It's better to use several 1farad capacitors over a single 10 farad capacitor - The 1 farad caps will be able to discharge and recharge faster than a single 10 farad cap.



Interesting thought...I've never really considered this. Is this based on the 1 farad caps having a lower ESR than a single 10? If so, how would the inherent losses of all the seperate connections of the 1 farad caps weigh in?

This is probably thinking way too hard about absolute minutia, but hey, this is AHQ!

Toby

[Paul]

I only ask..because when I play my music for the 1st time of the day..its really loud..as the bass hit...you can tell it falls off...like its getting weak.

would this help the amp's volts from falling off?

[Notladstyle]

I only ask..because when I play my music for the 1st time of the day..its really loud..as the bass hit...you can tell it falls off...like its getting weak.

would this help the amp's volts from falling off?

Nope wont help with gradual decreases, only an instant fraction of as econd demand.

[Skee]

drop in a 2nd batt/

[Notladstyle]

Interesting thought...I've never really considered this. Is this based on the 1 farad caps having a lower ESR than a single 10? If so, how would the inherent losses of all the seperate connections of the 1 farad caps weigh in?

This is probably thinking way too hard about absolute minutia, but hey, this is AHQ!

Toby

the greater esr plus I know theres a logarithmic charge rate difference based on capacity... which I cannot find a source for so I'm going to just lean on the esr.

[TpaS13]

Second lesson...skip them...they are useless (pokes dalton in eye).

Toby



+1 Ive only seen a SLIGHT difference in power on my buddys car, He was using 4 1.5 F Caps...and really it was a waste of space....


Do your "Big 3" if you havent already and that makes a nice difference for some vehicles.

Also, make sure your running the right size wiring. I would run a 4 Ga wire for that amp, and make sure you have a GOOD ground.

And finally, I added an extra 4 Ga ground wire on my battery, and it actually helped I was really supprised to see.

Rob

[aaron1017]

Caps are a bandaid.

[03AcuraCLTypeS]

First lesson...the term Farad Cap is like saying ounce glass. Farad is a unit of measurement...it is not a type of capacitor. A 10 farad cap stores 10 times the energy of a 1 farad cap.

Second lesson...skip them...they are useless (pokes dalton in eye).

Toby


+24529458098245 finally someone who agrees with me .....they are usless especially if your going to be bassing out for a long period of time running a lot of power, for your 600 watt kicker u should even need a cap...im running over 1400 watts in my system and dont have a cap though i do have a spare battery... i look at it this way in order to use the power of the system u have to have enough power to make it work right...adding a cap doesn't add power it jsut stores power thats already there...really not doing a whole lot as compared to a batter which actually adds power... my lights dont dim at all with my current set up...my last set up i had 2 1 farad caps on a 1000 watt system in the same car and i get light dim like a mofo once i bassed out for a while

[Notladstyle]

They are not useless they are inapplicable to a broad range of situations.

[03AcuraCLTypeS]

ok so in a lot of cases they are completely usless

[Notladstyle]

ok so in a lot of cases they are completely usless

exactly.

[MCOR]

Caps look cool and that is why they sell. As far as actually helping in the real world, good battery connections, proper guage wiring and solid sanded ground, that is where we find most problems. If all is good, we install two Optima gel-cells and battery isolator. When we are breaking 3k watts on reallly large systems, we finally do a dual Stinger 160amp alternator setup with 0 guage wiring complete (adding the most recent Denali pickup we just completed like this to our myspace slideshows this weekend-check it out MySpace.com - MCOR AUTOMOTIVE LLC - 32 - Male - Land O' Lakes, Florida - www.myspace.com/mcorautomotive (http://www.myspace.com/mcorautomotive) ).

Bottom line-caps are "pretty" in most cases-we sell quite a few due to customer request-mostly our high school clientelle.