yes but the load is absorbed before the current spike ends since the amp is no longer requiring current the alt can recharge the cap without affecting current output to the amp. And the capacitor is never emptied since it only drops as low as the nominal voltage that the amp sees which may be 9 volts.

 

YES... but only if you've already completed the big three upgrades.

A cap will allow your amp to use more current faster which will give you a higher peak output(as in harder hitting PUNCHES) with slightly less light dimming.

All amps have stiffening power supply caps. These capicitance variesby the amp from 10,000uf[.01 farad] to 200,000uf [.2 farad]. Generally they are meant to satisfy the amplifiers internal voltage surge requirements but they usually do not take into account the power supply short comings(your 4ga power wire, voltage regulator, and slow battery chemical response).


The two capacitors next to the coil on the right are part of the filter to remove engine hum and to regulate the power supply. The two near the middle are stiffening capacitors valued at 8,200uf each. They will maintain the power supply during peak demands from the internal circutry. By adding external capacitance ** when properly installed ** will allow the amplifier to channel more current faster.


CAPS will allow MORE power to be used BUT NOT BY THE CAP! BY THE AMP!

 

You have to remember that, even in Dalton's liberal example, you will get an extra couple of volts, for a whopping quarter of a second, at 50 amps, with a 1 farad cap. To me, that's worthless.

Now, if you step up to a 10 farad cap, that would give you 2.5 seconds. Starts to sound worthwhile, but like Dalton said, you only need the cap input until your alternator and battery can catch up, which, unless you are at the full capacity of the alternator, won't take 2.5 seconds. So, for the most part, 10 farad becomes useless.

There are places where big caps come into play, and one place is in DB contests, in classes where the engine must be off. In these situations, .1db can mean alot, and you don't have the alternator to save you. Here, 'burps' are sometimes only a couple seconds, and 25 or 50 farads of cap can help.

All that being said, caps are like engine performance chips that promise 10 hp. If you want to believe it, you will notice the difference. And if you've put every other upgrade in, and just have to throw out some more money, you can either upholster your car with it, or really waste it on a cap.

Toby

 

So, first, there is no load. Now, there is a load, but it doesn't count in this case. Man...when are you going to run for office

FWIW, I agree that the load presented by the cap doesn't matter. But, since I think the cap is useless, why have the extra load...

oh, wait...this is Dalton...why didn't I see this before...caps are good because...

 

The differing of opinion here is not in the facts! Thats excellent. Its in whether or not that fraction of a second actually means anything.

As toby said, if you want to see it, you will. Mathmatically there is a gain. Whether or not you will see real world improvements in performance, I couldnt tell you because I dont have the equipment to measure that... maybe someday or when one of my teachers lets me borrow the needed equipment.

I do know my lights dont dim as much with a simple 1farad stiffening cap... that had no blinking lights =( I also know if you hook it up backwards it loses a great deal of its capacitance and makes a big spark.

 

ouch...

Trying to follow this whole debate but its too late to think but I figure I might toss a couple things in.

1.Isn't it true that the discharge rate of a cap would have an effect on how long the cap holds a charge?

2.The discharge rate of a cap is theoryectically inversely proportional to the resistance. Or is the changes in resistance so small that they don't don't really matter and a cap appears to discharge almost instantaniously?

Feel free to correct me or add to it cause i'm pretty much just starting my electrical engineering degree and i'm trying to apply some of the things from my classes to cars. I understand how things go together and why, I'm trying to learn the actual math and science behind it.

 

i remeber that car!!!!!!!!!!!!!!

 

First off, YEY EE!!! Are you going to USF? If so we might run into eachother in some classes.

now for the Qs

1. The discharge rate is directly related to its voltage. So more than 60% of a 1farad capacitor is useless as it will supply current below 9-10 volts. Thats why you will only get about a 1/4th of a second of usable power. But thats all you really need in the intended application.

2. Yes the higher the resistance the slower the capacitor discharge. Thats why the cap must be as close to with parallel connections (+12v AND ground) to the capacitor.

In the same spirit, if you examine the printed circuit board of an amplifier, the power supply conductors to the capacitors are always 300% to 500% larger than the rest of the conductors including the output leads! Also keep in mind that the ESR from the capacitor to the amplifier (even when including the conductors that connect the wires) will be several times less than the length of copper wire to the battery and its own connectors.