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**matador** · 18-02-2009, 13:47

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Lesson 4

In the actual real world the voltage of the battery would drop a litt f_r_o_m- i_t_s- o_p_e_n circuit voltage of 12.8 volts with a 65 amp load. In the case of the yellow top its actual voltage at 65 amps is about 12.2v when fully charged. By the end of the hour it would be down to about 10v. If we use 11 as an average our answer would be........ 2,574,000. Now that's still a lot of joules! Now actually this is not enough to totally kill the battery but at this point there isn't much left in it. This brings us to a very important fact. The energy in a battery will be depleted almost completely by the time it is down to 10 volts.

By the time we have removed those 2.5 million joules from the battery it probably doesn't have more than a hundred thousand joules left. We can almost totally deplete the battery's energy and never drop below 10 volts. This is because the battery doesn't store electricity. It stores chemicals. A chemical reaction produces the electricity. Storing actual electrical charges is very inefficient.

Look at our poor capacitor. Even if we made one as big as a battery it would still only be good for perhaps fifty to one hundred thousand joules---less than that left in a nearly dead battery. But if that were not enough there's more bad news. This exercise will be tonight’s homework.

A capacitor is like a gas tank in a car. The pump can only remove gas down to the pickup point. Any gas below this point can never be removed by the pump. If we charge a 20 farad cap to 14 volts we know from previous lessons that it will contain 1,960 joules. If we use that cap in a system and load it till it drops to 10 volts along with our battery how many joules will we have removed from the cap? How many joules will remain in the cap that we can never benefit from if our system never drops below 10 volts?

Lesson 5

In our last lesson we learned that caps actually store charges on their plates. And of the 1960 joules stored in a 20 Farad cap, 1000 of them sit at a potential below 10 volts. This means there is no way they can ever be used by an operational audio system. Today we will look at another loss factor. It has to do with the loss factor due to the ESR of the cap.

We have already studied voltage drop due to ESR but now let’s view it from an energy/watts standpoint. Let’s clarify things. The power delivered to the stereo by the battery and alternator bypass the cap. They merely flow by its terminals. If the cap charge is lower than the battery/alternator potential current will flow INTO the cap until it reaches equilibrium with the Battery/Alternator. If the B/A potential is lower than the charge potential of the cap current will flow OUT of the cap to the battery and or the amp.

Always remember that voltage always flows from the highest potential to the lowest potential, just like water. Current does not however flow into the alternator even if it is lower than the battery and cap because it has diodes on its output that only let current flow FROM its output. Now whenever any current flows into or out of the cap it must pass thru the ESR of the cap. The resistance is really distributed throughout the cap but it behaves just like it was right on the output terminal as in a series circuit location in the circuit loop does not matter. Now suppose our 20 farad cap is charged to 14.2 volts and we place a load on its output. This load is the same one that we used in lesson 2 to cause 100 amps of current to flow from our unlimited capacity cap. Only now we have our smaller 20 farad cap.

Lesson 5

In our last lesson we learned that caps actually store charges on their plates. And of the 1960 joules stored in a 20 Farad cap, 1000 of them sit at a potential below 10 volts. This means there is no way they can ever be used by an operational audio system. Today we will look at another loss factor. It has to do with the loss factor due to the ESR of the cap.

We have already studied voltage drop due to ESR but now let’s view it from an energy/watts standpoint. Let’s clarify things. The power delivered to the stereo by the battery and alternator bypass the cap. They merely flow by its terminals. If the cap charge is lower than the battery/alternator potential current will flow INTO the cap until it reaches equilibrium with the Battery/Alternator. If the B/A potential is lower than the charge potential of the cap current will flow OUT of the cap to the battery and or the amp.

Always remember that voltage always flows from the highest potential to the lowest potential, just like water. Current does not however flow into the alternator even if it is lower than the battery and cap because it has diodes on its output that only let current flow FROM its output. Now whenever any current flows into or out of the cap it must pass thru the ESR of the cap. The resistance is really distributed throughout the cap but it behaves just like it was right on the output terminal as in a series circuit location in the circuit loop does not matter. Now suppose our 20 farad cap is charged to 14.2 volts and we place a load on its output. This load is the same one that we used in lesson 2 to cause 100 amps of current to flow from our unlimited capacity cap. Only now we have our smaller 20 farad cap.

We know that if 100 amps of current flows out of our cap, those 1.7 volts will drop across the ESR of .017 ohm. This will cause the output to drop to 12.5 volts just like it did with the unlimited cap.

This means that the load (100 ohms resistance) will be consuming 1250 watts from our cap. 12.5 volts x 100amps = 1250 watts. The total wattage output produced by the cap is 1420 watts. 14.2 volts x 100 amps = 1420 watts. Unfortunately 170 watts of power will be lost in heat in the ESR of the cap. This represents a loss of 13% of our total usable joules (960) at this point. Now tonight’s question is if we increase the current draw to 300 amps (300amps x 14.2volts = 4260 watts), how many watts will be dissipated in the ESR of the cap and what percentage of the total 4260 watts does it represent? Of our total usable 960 joules, what percentage will be left for the stereo?

Lesson 6

Ok before the next lesson let’s review lesson five. When I checked the posts no one had the correct answer of 56% but some were close. The important part is that everyone seems to understand the loss mechanism. From lesson five we see that the energy we can get out of a cap is inversely proportional to the rate that we try to take it out. This is because the ESR that is in series with the output stays constant regardless of the load. At very high power levels, this ESR can amount to a sizeable amount.

In an earlier lesson we learned that the ESR causes a voltage drop proportional to current flow. When voltage is dropped across a resistance heat is created. Lesson five taught us that with 100 amps (flowing from a cap with .017 ohm ESR) we lose 13% of our joules as heat when we try to remove them. If a cap has an ESR of .017 ohms, and 300 amps flows we will lose 56% of the stored energy when we try to remove it. In our giant cap example with 300 amps of current, we will lose this as 1530 watts of heat. This is the same loss mechanism that causes a battery or amp or power supply to get hot when they are delivering high power levels. Virtually all voltage sources have at least some ESR. At this point we should have a good understanding of how ESR affects a component. The next logical thing to cover is ESL.

ESL stands for equivalent series inductance. Just like the ESR it can be modeled as an inductor in series with the output of our capacitor. Now everyone in car audio knows what inductors do. They resist a change in current flow. Their most common use is in speaker crossovers. When used in series with a woofer they let the slowly changing low frequencies pass, but stop the fast changing high frequencies. The reason an inductor does this is because it behaves like a resistor that changes value with frequency. Unlike a capacitor that decreases in value with increasing frequency an inductor decreases in value with decreasing frequency.

Now I have been told that the ESL value of the giant cap is 0.2 mh. Somebody check my math but I think this would put the reactance of the cap near .063 ohms at 50 Hz. This means that if we wanted to refresh our amps at a rate of 50 Hz (seems reasonable if we were playing bass real loud) our ESL of .07 ohm would be in series with our .017 ohm ESR for a total value of .08 ohms.

Now we know from ohms law that if we try to get 100 amps through .08 ohms we will have a voltage drop of 8 volts and at 300 amps the drop would be about….well it’s pretty clear that we will be left with less than a fraction of a volt if we start out with only 14.2. Is everybody still with me? I know it’s not good news but I’m not making this stuff up.

Now for tonight’s lab lesson to prepare us for lesson 7. Tomorrow, I will post the results of the following test. If you want to check me, go to Radio Shack and buy the following: Bulb # 272-1127, Socket # 272-360, and a nine volt alkaline battery. For the battery a Radio Shack is ok but a Duracell is better. Make sure it is fresh!!!!!

Wire the socket and connect it to the nine volt battery and record how long the bulb stays lit. Be prepared to wait for a couple hours. Charge a giant cap to 14.2 volts and do the same with it. Be prepared to wait about an hour. Charge a 1 or 1.5 Farad cap to 14.2 volts and do the same. This will take only a few minutes. Record the times and we will discuss the importance of this in our next lesson.

Lesson 7

Ok in last lesson I left everyone with instructions to duplicate the results of the test I am going to post tonight. The purpose of this test was to put the capacity of even a giant cap in perspective. As I have pointed out in earlier lessons storing electrons in the form of a charge on a plate is not really very efficient. Some folks think we should stand in awe of a value like 2000 Joules. Well our test tonight puts some reality in this value. If we perform a test like described in the end of lesson 6 we come up with the following results.

1.5 Farad cap lights the bulb for about …………5 minutes and 28 seconds

a giant cap lights the bulb for about……………. 54 minutes

a nine volt alkaline does so about …………………. 2 hours and 14 minutes

did anybody get results similar to these…….are we in agreement on these numbers ?

As for the relationship of these numbers, each of these units has a higher ESR than the previous one. The highest ESR in the group was the nine volt battery. It actually has enough energy to light the bulb far longer but since its ESR is fairly high it loses a lot of its energy as heat internally. But even still it should be apparent that it holds more energy than the giant cap and a whole lot more than a 1.5 farad unit

For now I do not care to concern ourselves with the meaning of this ---we will cover it in the closing. Before going on let’s review a few facts. In lesson 3 we learned that a giant cap can hold 1960 joules at 14 volts. In lesson 4 we learned that only 960 of them sit at a potential above 10 volts. In lesson 5 we learned that if we want to use them at a rate of 100 amps we will lose 13% of the 960 that are left.

If we use them at a rate of 300 amps we will lose 56% of the 960 which will leave us with only about 500 usable joules. And these losses are only for the ESR mechanisms—they do not include the ESL mechanisms that could actually be higher if the demands are quick enough.

It has been suggested that the purpose of these giant caps is to provide quick energy. It has also been suggested that they are for slow energy.

I am not sure what is being claimed so I guess I need to cover both situations. As for slow energy I think the previous test could put that thought out to pasture. For long term energy one of these units is less useful than a nine volt battery and to compare it to a car battery is really useless. After all what good is 500 useable joules when we have over 2 million in the car battery? It should be obvious if one of these devices can be of any use at all it will have to be able to provide energy faster than a car battery. But before we get to that issue lets cover the behavior of alternators and batteries under dynamic load conditions.

Tomorrow is Saturday and I will have time to measure the response time of a few alternators. This will enable me to model my closing explanations more exactly. I will post the results of these tests tomorrow night.

Lesson 8

For this lesson I have done some actual measurements. Here are the test conditions: To measure voltage we used an Audio Precision with a DCX module. It is accurate to three decimal places. For sample time we chose 40 samples per second. For the non audio system test I used a KAL carbon pile load tester. It can do power tests on 12 volt charging systems up to 1200amps continuous. The audio system consisted of a couple of Rockford 1100 amps bridged into four ohm nominal speakers. The alternator was a stock Delco 80 amp CS type unit.

Lesson 5 (continued)

Its case temperature was monitored by a Raytek ST2L IR sensor. Engine speed was regulated with a Thexton #398 IACV tester. The music material was the SPL track # 30 from the IASCA competition disc. The battery was a Stinger spb-1000. All voltage measurements were done directly at the terminals of one of the amps.

Chart 1 Alternator/cap/battery test with 200 amp dummy load

For this test we monitored the voltage of the car with the stereo turned off. With the car running the voltage can be seen to be stable at about 13.7 volts. After 22 seconds (The horizontal scale is 100 seconds-10 sec per major division) we applied a 200 amp load. The voltage can be seen to drop to 11.6 on both traces. This test obviously exceeds the ability of the alternator to keep its regulation set point so its voltage falls. The drop can be seen to be nearly instant (steep curve) until about 12.5 volts where the battery starts to supply a significant amount of the power.

Ultimately the voltage drops to 11.6 and at 26 seconds we turn off the load. The voltage then starts to rise to the regulator set point as the battery is recharged (yellow curve) and as the battery and cap (green curve) are recharged. At a time of 50 seconds I turn the motor off so the alternator stops. The voltage then droops down to the float voltage of the battery—about 12.7. The only reason for the small difference at 50 seconds is because I couldn’t get the timing of the engine shut-off exactly the same every time. I did it several times and these two are within one second. That was as close as I could get it.

I am able to see no difference from these measurements. There are microscopic differences but I believe they are due to the alternator temperature. Alternator regulators are usually temperature sensitive. As they get hotter they tend to fold back. For this reason we let the unit cool off between each test and closely monitored the case temp throughout the tests. For this reason I believe that none of these measurements are meaningful to more than a couple tenths of a volt.

Chart 2 Music tests with an audio system

Note: Between each test the alternator was allowed to cool and the battery was charged until an automatic charger said it was topped off.

Purple curve

For our first test we played the system with the engine off and no cap. The result was the purple trace at the bottom. We played the system as loud as we could get it that seemed to produce no audible distortion. This was track 30 of the IASCA disc. It starts off with fairly low level sounds for the first 34 seconds. In order to insure the electrical system was stable we did not start the measurement until we were 20 seconds into the song. This means that our 0 starting point is: 20 on the CD counter. The battery was able to maintain its voltage just below 12.5 until the loud bass hits at 34 seconds (14 seconds into our chart) At this time it dropped to about 11.5 and had a few large variations due to the music. According to the computer calculations (third chart) the average voltage for this test was 11.7volts. This test was done as a baseline for the following tests.

Yellow curve—no cap

For this test the volume was left as it was for the baseline test. The engine was started. Notice that at low volume the alternator was able to maintain about 14 volts. When the loud music hit the voltage dropped to about 12.5 where it remained except for a few short moments where it actually climbed back to over 13.5 volts. The computer averaged calculations for the average voltage during the 100 seconds of this test was 12.973 volts.

Red curve—cap added

This test was identical to the previous test except the cap (15 farad type) was added 6 inches from the amp with 4 gauge wire—no relays or fuses. The red curve seems to overlay the yellow except that the actual peaks don’t rise as fast or as high during the brief quiet moments. I feel this would be due to the alternator having to recharge the cap. The voltage on loud passages hovered around 12.5 volts. The computer averaged calculations for this test show the average voltage to be 12.878 volts. I see no meaningful differences with or without the cap. I certainly don’t see the voltage sitting solid at 14 volts.

One note I might add is that this was a two thousand watt system driven right to clipping and the average voltage stayed above 12.8 with a stock 80 amp alternator. Under these conditions the battery would never discharge!

The green and blue curves were done just for kicks while we had the system set up. In both these tests we turned the volume up until the system was very distorted. This placed a severe load on the alternator and caused the voltage to dip as low as 12 volts. The curves seem to follow each other so closely that unless you have a good monitor it is doubtful you can tell there are two curves. The average voltage for these two curves was both 12.277 and 12.295 volts. If this volume were sustained for very long periods of time this battery would discharge.

Any questions? Please ask -- I will give everyone a chance to ask them before I sum this all up in lesson 9.

Lesson 9

Now that we have had time to study theory in each of the 8 lessons and the results of the actual tests on a real system it is finally time to bring this discussion to a close. Unfortunately, when this thread started I was unable to explain the concept, as it was obvious that many of the people posting responses just didn’t have a good grasp of the way things really work. Those of you who have taken the time to follow the lessons should know by now why I was so frustrated at the arguments that were so illogical. It is important to keep in mind that this is a technical forum, not a marketing forum. I do not care or want to know about companies or brand names.

Nothing I have said was ever meant to disparage a particular product or company and I would appreciate it if in the future we could always keep that in mind. We should be able to discuss the merits of radial vs. bias ply tires without caring if they are made by Michelin or Goodyear.

In car audio we have little choice of how we are going to power our systems. Presently we have only four things that are practical. Each of them has its own characteristics that incorporate good points and bad points.

Let’s review them

The battery--this device has the ability to provide a very large amount of current. But due to its nature the current is provided at a voltage that is less than optimum –at least for a high powered stereo. Since its float point is 12.8 volts if fully charged, it can provide current only at voltages that are proportionally lower than 12.8 Volts.

The alternator—this device is electronically regulated at a point that allows it to recharge the battery. The alternator is usually designed to output voltage in the 13.8 to 14.5 volt range. Because its output is actively regulated it attempts to maintain this voltage with varying load conditions up to the point where it’s output cannot keep up with the load at which time it’s output drops off very rapidly. While relatively tight regulation is the strong point of the alternator it’s weak point is that it simply is not practical to obtain one that can provide large amounts of current like a battery is capable of.

The capacitor. The advantages of a cap are that it can charge up to whatever the highest voltage source in the system is, (in a car this would be the alternator) and provide current at this elevated voltage. The down side of a cap is that it cannot store very much total energy and only a portion of this energy is available at a usable voltage potential. The fourth type of device is an electronic voltage regulator. These devices have not been part of this discussion so I will pass over them for now.

Now modern car audio amplifiers are capable of consuming enormous amounts of power. Even with efficiencies in the range of 60% to 90% an audio system is capable of drawing hundreds or thousands of amps from the cars electrical system. Typically, the audio system is larger than any other electrical device in the car including the engine starter. Fortunately for the car, the demands of an audio system are rarely continuous in nature. The very nature of music rarely demands more than a duty cycle of 10% to 20% from a power standpoint. This means that the audio system is demanding short term, but repetitive peaks of current from the electrical system.

The primary source of this power is the alternator. It should be considered primary for two reasons. The alternator is the only first generation source of power. It ultimately provides all the power for the system either directly or indirectly by restoring power to the battery or cap. It is also primary as it is the power source with the highest voltage potential. In an electrical system current always flows from the source of highest voltage to circuits of lower of lower potential.

All three devices can be used in a system to great advantage. But the dynamic conditions present in a music system determine the role each device plays and to what degree. To understand this lets consider a low current drain condition. In this scenario the alternator will be at or near its set point.

This voltage is designed to be high enough to charge the battery meaning it will be one or two volts above 12.8 volts. This means that the battery will actually be a continuous load on the alternator and provides no power to the system. The size of load it presents is determined by the state of charge of the battery. The higher its state of charge the smaller the load will be. A cap if present in a system in this state will present a load for a finite amount of time until its charge voltage reaches equilibrium with the alternator.

Unlike the battery, the cap will cease to be a load after it is charged except for a factor known as dissipation, which for all practical purposes can be ignored in this application unless it is excessive. Under these circumstances, as long as the alternator can maintain its set point, it will provide all the power for the music system and the rest of the cars accessories. The battery and cap may as well not even be in the car.

Now if we increase the current demands of the music system to an amount that taxes the alternator its output voltage will begin to drop. Even so the alternator will continue to be a source of current to the system –i.e., the car, music system, and battery. It is at this time that the cap will begin to discharge and begin to augment the alternator as a source of current. The degree to which it provides current to the system is dependent on the actual voltage at the alternators terminals. Only when the alternator begins to drop below the caps charge potential does current flow out of the cap.

This is a continuous process and the current provided by the cap tries to maintain the voltage at its charge potential. The degree to which it can do this is dependent on two things. The current provided by the cap is limited to the total capacity of the cap and any series reactance’s (resistive or inductive components) that are part of the cap. The instant the cap starts to output current its charge potential begins to drop.

Now just what can we expect the cap to provide? Suppose we happened to have a cap charged to 14 volts, with a total reactance (made up of either resistive or inductive components) of about .017 ohm. We could figure that at the first instant of discharge it could provide ten amps at 13.83 volts. Of course if we were playing the system at a level enough to load our alternator, ten amps is not likely to provide much relief. But perhaps 30 amps might help—at this modest level our cap could begin to provide current at a potential of 13.5 volts. (lesson 2).

Of course this voltage level would drop at an exponential rate commensurate with the discharge curve that is standard with caps. No doubt the cap could help out a hundred amp alternator with the addition of an extra 30 amps even though it might be for only a brief instant. But it is sort of interesting that at even this modest power level of 130 amps (100 amps alternator + 30 amps cap) the cap is unable to maintain the voltage at 14 volts.

Of course in this scenario we are sitting at 13.5 volts for a brief instant and our poor battery is unable to help at all as its potential is at a lowly 12.8 volts. In fact the battery is still a load on the system!

Now what if we get serious with our stereo and we really crank it up? Lets say we have something like a manufacturers demo van with lots of amplifiers that can draw hundreds of amps on musical peaks. Lets pick a nice round number like 500 (“Cade” said 490) amps. Lets say we have a 200 (“Cade” said 190) amp alternator. Typically such an alternator can maintain a voltage near its set point up to perhaps 80% of its rating-after which its voltage begins to drop as it provides large amounts of current. As I am not familiar with all the different alternators lets just assume these assumptions are close and our alternator is putting out 200 amps. Well our amplifiers in an instant are asking for 500 amps so what happens?

In any constant voltage system when the current capability is exceeded the voltage drops. So let’s say our alternator voltage starts dropping. What does our cap do? Since its charge potential is at 14 volts it starts to discharge and provide a source of current. Since the cap is now sharing the load with the alternator it is called on to provide what the alternator can’t—that would be 300 (see footnote) amps.

What happens to the terminal voltage of our cap when 300amps is flowing? Well for starters, the voltage tries to drop nearly 5 volts inside the cap before it can even get out. Not in a short time but instantly. There is no time constant in the formulas for ohms law. They are instantaneous calculations! But wait. The voltage doesn’t really drop to 9 volts because we have our battery sitting in reserve waiting at 12.8 volts.

Our cap lets our poor alternator down as the voltage plummets and when things hit 12.8 volts our battery jumps in and starts to take over. The battery with its enormous storehouse begins to provide vast amounts of current until things lighten up for our poor cap and alternator. Of course we could add another cap to halve our ESR loss to only 2.5 volts but that would still cause the cap terminal voltage to drop to 11.5 volts.

Let’s see how many caps of this spec we would have to add to keep the voltage at 13.5 for even a few milliseconds. We would need a cap bank with a total ESL of about .001 ohm. Gee it looks like it would take over thirty caps paralleled to maintain 13.5 volts at 300 amps for even a brief instant. And let’s hope we don’t need to do this for long, as the total power contained in thirty units is only about what is in a dozen 9v alkaline batteries! (lesson 7)

It should be clear that if the voltage doesn’t drop the caps don’t do anything. The voltage MUST drop for them to start discharging.

Now, is it possible to have a steady 14 V because we added caps? I don’t think so.

http://forum.sounddomain.com/ubbthreads ... 776/page/1

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**matador** · 18-02-2009, 14:13

dt var den første, nå kommer en annen som er litt enklere forklrt og faktisk meget morsom kommentar i "hva er en kondesator godt for?"...

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After studying a little history on large 1 Farad capacitors in car audio, you'd be amazed that they even sell at all. How useful are they? What do they really do? Will a Cap 'improve' my sound quality? Will it Prevent my lights from dimming? Will it audibly affect my audio system in any way?

Before you get the truth to any of the above questions, chances are, you've probably spent $100 or more on one of these devices. However, let's study a little history regarding this issue.

A long time ago, in a land far away, 2 elves...Ok, Richard Clark & Wayne Harris (Carsound magazine and the inventor of DB Drag, respectively) separately came up with a solution to preventing their lights from dimming.

WHO WERE THESE GUYZ?

As you may know, Richard Clark is one of the founders of autosound2000 Tech Briefs, Carsound magazine, and a published author of the industry of mobile electronics. In SQ competitions, he posted a record of 1234 1st place finishes, and only ended up NOT 1st in his first event. I've heard that he had minor system problems, but judging by his record, he must have corrected it. (evidently, he needed a Capacitor )

Wayne Harris was previously a leader at Rockford Fosgate in their development. Later, in his free time, he created the organization we call DB DRAG. Wayne was the first SQ World Champion from the organization we know as IASCA (International AutoSound Challenge Association).

Both of these gurus are both legends, and considered the leading experts in the field. During their competition days, both guyz came up with a way to assist in the prevention of voltage drops. In SQ competitions, the look of your system is actually more important than the sound, and having your lights NOT dim under high playing levels is a competitive advantage.

As you may know, amplifiers are made up a bank of little capacitors, resistors, etc. What has been common engineering knowledge is that capacitors store energy, and more or bigger ones assist in balancing the power supply.

Wayne came up with the idea of putting several dozen 'little' (approx 100uF) capacitors on a circuit board to 'extend' the power supplies storage. At about the same time, or shortly afterward, Richard came up with the idea of one huge mondo capacitor (I believe it was 800,000uF or 0.8F) to do the job.

Eventually, Richard won. The large cylindrical tubes won over the complicated 48 caps strapped to a circuit board. However, what did this really accomplish? Let's start here:

WHAT IS A CAPACITOR?

Basically, capacitors are an energy storage device. Large, 1 Farad or more
capacitors store energy (electrons) between their plates. Capacitors differ
from batteries because batteries store energy in the form of chemical
energy--and rely on acid and lead plates, as the place of storage. For a more detailed
description of a capacitor, go here:

http://www.eatel.net/~amptech/elecdisc/caraudio.htm

Then on the right hand side, scroll down to CAPACITOR. Keep in mind the use
of capacitors in an audio system.

WHY DO PEOPLE BUY CAPACITORS?

The number 1 reason would have to be because their lights dim when their
system is playing HARD. In car audio, we are told that a capacitor is
designed to prevent the voltage drop associated with your lights dimming.
The number2 reason is that it is rumored to 'improve' sound quality or
'stiffen' the power supply/source.

WHY DO MY LIGHTS DIM?

Headlights brightness is in direct proportion to the source voltage. For
instance, if your car is running, system voltage is ~12.5 -14.4 VOLTS. Your
lights will be much brighter than when your car is turned off--where battery
voltage is ~12V. Most car alternators put out between 75 to 120 amps of
current. When this current draw threshold of the charging system is
exceeded, system voltage will drop as power demands are now shared by the
alternator and the storage devices (battery & cap). We are using battery
reserves beyond this point until the demand lessens

When playing your system really hard. Your lights dim because your
alternator can't keep up it's charging voltage (around 13.5V) and therefore,
demand exceeds output. When this happens, your electronic devices are
dipping into the power storage of the battery. Since the battery stores
power at ~ 12-12.5V, there is a 1.3 to 1.8V drop in voltage available. This
in turn is why your lights dim down.

HOW MUCH POWER DOES A CAPACITOR STORE?

1 Farad = 100 joules or 100W/second
850cca battery = ~2,200,000 farads

For storage purposes, you'd need ~2,200 1 Farad capacitors to equal the energy of your battery.

Due to its impedence (ESR & ESL), a cap's energy is only 50% available. What's worse, is that in order for a 1 Farad cap to discharge, first the alternator output must have maxed out, and the voltage must have dropped around 1.5 volts. But I thought a cap was supposed to prevent that (voltage drop)!!!!!????? Yep, you got the point.

IF A BATTERY = 2,200 CAPS, THEN WHY BUY A (PUNY) CAP?

My question exactly. Marketing is the reason why people buy caps. In many cases, upgrading wiring will help your system get the maximum transfer of current. Once that has been reached, adding a capacitor may have a minor effect on your system. 50W over the course of a second is not a lot of power considering an amplifier may draw 2000W to put out 1400 watts. Let's look at the situation from a resources standpoint.

Alternator 80 amps
Car accessories (minus stereo) 40 amps
A large Car Audio system (DRAWS ) ~200 amps AT FULL OUTPUT

In this case, you have 240 amps of draw, but only 80 amps of current from the alternator. In your case, you need 160 amps x 12 volts or or let's say 1920 watts of energy. Since a cap stores 50W, how much of a difference do you think it's going to make? A cap is basically a peashooter. W+e need a Howitzer cannon here, to do the job well.

Also, Once a cap is discharged, where does it get it's power from? The alternator, which is already overloaded. Once a cap is discharged, it's worthless. Like SWEZ says, ・.The cap already shot its wad, an does limp til recharged・ I知 not so certain I will allow him to babysit my kids, but you get the drift. (I never said it quiet like that... and oh...I'm great with kids!)

SO, WHAT IS A CAPACITOR GOOD FOR?

1. Audio Jewelry- impress chicks with large cylindrical shiny thingy
2. Extra weight in winter time
3. A very POOR... BUT expensive distribution block
4. A projectile in the event of a crash
5. Rolling pin--for cooking purposes
6. A neat thing to tell your friend, "..Hey man, lick the top of this..

Please do not try # 6. New hairstyles are always refreshing, but if you are wearing railroad tracks across your teeth, you might have one big filling after it痴 over.

HOW CAN CAPACITORS IMPROVE SOUND QUALITY?

They can't. Sound quality is not dependant upon the presence of large bulky 1 Farad capacitors. How many 1 Farad Capacitors do you think the Boston Pops, Aerosmith, or Snoop dog use in the recording studio?

IN A NUTSHELL.......

When Richard, our fearless inventor, became World renown for winning every competition under the sun, people began copying what he did. Soon, every 'serious' competitor had a 'stiffening' capacitor--not to be confused with the 'loosening' capacitor.

WHY?

In the late 80s, people began sticking out their tongue when dunking the basketball because Michael Jordan did. Did sticking out your tongue improve your dunking ability? Same here with adding a capacitor to your electrical system.

Phoenix Gold's marketing guru had just posted information on how their Powercore (basically the Alumapro CAP15 in a Phoenix shell) had both stabilized their voltage and improved the sound quality. Richard called him on it (all in another post) and the marketing geek was unable to quantify any of the conditions that resulted in the voltage being HELD at 14.2V and the 'improved' sound quality.

Please do not read every stinking post as valid. There are a lot of people that have had the efficacy of capacitors inbred to their minds, and were not (and still not) convinced in the futility of a 1 Farad storage device.

In a final note, Richard relayed a quote regarding battcaps ( www.battcap.net ) as, "..The audio industry is the only place i know of where you can publish specs that show your product is useless and still be able to sell them------and whats worse is that technically ignorant people will argue against the math!!!!!!!..............RC.." when referring to the product. This also relates to most digital readout capacitors, and I wish my Archie Bunker skills could have said it better myself.

Cliff Notes: Caps are pointless. Get a better alternator, do the Big 3 (http://www.the12volt.com/installbay/...TID=73496&PN=1) and get a stronger battery.

-------------------------------THE END??------------------------------

**Erik André** · 18-02-2009, 14:25

What a fucking waste...

**r3mark** · 18-02-2009, 14:36

Litt mye å lese, men BRAVO!

**chin** · 18-02-2009, 15:34

har SÅÅÅÅÅ mange venner som skal få tilsendt denne linken og jeg skal stå bak dem når de leser den..

Nei, jeg har ikke noen kondensator i bilen selv, aldri hatt det, og jeg kommer aldri til å ha det, i hvertfall ikke etter at jeg så effekten som ett nytt batteri hadde på anlegget i bilen i vinter. Og nei, jeg er ikke profesjonell innen bilstereo heller, så det å lytte til erfarne fjellfolk er faktisk ikke så dumt når det kommer til stykket.

Takk for interessant lesing, matador.

**matador** · 18-02-2009, 16:31

fant forresten en link til i bilforumet med samme info men den linken peker til berømte og velkjent "realm of excursions"...selv fant jeg den i en annen utenlansk forum. anyway, det er bare å lese. Det finnes en annen link med mye matematik men den forteller med tall det samme...

--samme info i en annen link--

**Bluum** · 18-02-2009, 23:41

Der var det MYE å lese, også på engelsk da mann!
Hvorfor skal alt være på engelsk når man blir voksen :P

Skal inrømme at jeg hoppet over en god del linjer, men fikk med meg essensen i det hele tror jeg.
Jeg har selv en 10F hybridkondensator i bilen min, og etter å ha lest (deler) av dette her, så skal jeg ta meg tid til å koble fra denne kondensatoren og se\høre etter forskjeller.
Har svært sjelden problemer med lys som dimmer, men det har skjedd en gang og to, på tomgang og med bassen på max. Det blinker ikke i takt med musikken, men etter noen sekunder hvor forsterkeren har trukket det den kan, så har lyset blitt svakere.

Vet ikke helt hvem jeg skal tro, produsentene\forhandlerene, eller kritikerene.
Innen hi-fi vet jeg det finnes mange merkelige meninger og produkter, men hvis jeg merker en positiv forbedring av å ha kondensatoren tilkobla, så blir den. Hvis ikke går den til førstemann med en tusing i neven.
Skal bli artig å faktisk sjekke, ikke bare å tro

**Erik André** · 18-02-2009, 23:57

Originally posted by Bluum View Post

Der var det MYE å lese, også på engelsk da mann!
Hvorfor skal alt være på engelsk når man blir voksen :P

Ja sånn går det når man må copy/paste andre sine teorier, i steden for å stole på sine egne.

Skal inrømme at jeg hoppet over en god del linjer, men fikk med meg essensen i det hele tror jeg.
Jeg har selv en 10F hybridkondensator i bilen min, og etter å ha lest (deler) av dette her, så skal jeg ta meg tid til å koble fra denne kondensatoren og se\høre etter forskjeller.
Har svært sjelden problemer med lys som dimmer, men det har skjedd en gang og to, på tomgang og med bassen på max. Det blinker ikke i takt med musikken, men etter noen sekunder hvor forsterkeren har trukket det den kan, så har lyset blitt svakere.

Dette liker jeg.. praktisk teste dette, teoretikkere med heller dårlig eller ingen lyd i egen bil som er eksperter har vi nok av.. teste ut i praksis gir faktisk resultater du selv kan stole på.

Vet ikke helt hvem jeg skal tro, produsentene\forhandlerene, eller kritikerene.
Innen hi-fi vet jeg det finnes mange merkelige meninger og produkter, men hvis jeg merker en positiv forbedring av å ha kondensatoren tilkobla, så blir den. Hvis ikke går den til førstemann med en tusing i neven.
Skal bli artig å faktisk sjekke, ikke bare å tro

Stol og tro på deg selv

**Engen Audio** · 19-02-2009, 00:27

Støtter EA.

Ta en bil som har lagt opp gode kabler, bra dynamo, bra med batterikapasitet, ett bra anlegg og test med og uten kondensatorer. Er det noen her som har gjort det bortsett fra meg ? og hvilket resultat kom dere frem til ?

**Erik André** · 19-02-2009, 01:00

Originally posted by Engen Audio View Post

Støtter EA.

Ta en bil som har lagt opp gode kabler, bra dynamo, bra med batterikapasitet, ett bra anlegg og test med og uten kondensatorer. Er det noen her som har gjort det bortsett fra meg ? og hvilket resultat kom dere frem til ?

Jeg har testet dette for en stund siden, fikk en bedring i dynamikk i bilen. Men dette var testet på musikk som var dynamisk og ikke en spl skive som konstant trekker opp mot maks strøm. Var testet på Audison VRX forsterkere, JL audio subwoofere focal utopia frontsett.
Et batteri montert bak og et foran i original possisjon (begge var av merke Stinger SP1000), kabler overdimensjonert. Dynamo var 120A hvorav 70A var originalt

Var Stinger Pro kondensatorer på 1.2Farad pr stk

**neptyr** · 19-02-2009, 01:05

Hadde vært gøy å hatt en switchboks, slik at man kunne slått dem direkte av uten å måtte koble om.
Burde jo være fult mulig å bruke f.eks en bryter til båt?

**Hifonic** · 19-02-2009, 10:27

Spent på om EA hadde hørt forskjell om man kobla bort kondisen uten at han visste det ja

Og om man leser alt som matador har limt inn skjønner man jo hvorfor kondis ikke funker så bra i praksis som mange skal ha det til.

**matador** · 19-02-2009, 11:14

jeg har prøvd det engen, derfor har jeg alltid ment det samme om kondiser og "desverre" i tilleg så forstår jeg meget godt hvordan den fungerer teoretisk i en kompleks krets. Greie er bare at uansett hva det er så vil jo alltid være andre som mener noe annet

Det er for mange som mener og tror uten å forstå hvorfor og sammenheng, men jeg trenger ikke overvisse det som andre berømheter allrede sier. Jeg ble dritt lei av å nevne det samme hver gang EA. Men helt ærlig det er bare å bruke pengene sine som man selv ønsker -gjør meg ingenting...

men her har du en klar indikasjon om hva folk som virkelig kan dette bedre enn deg og meg mener om saken...

ellers jeg tror at de karene har både skrud og drivet lengre med bilstereo/lyd enn deg EA... og hvis du mente meg så har jeg drivet med det mye lengre enn deg med bilstereo og elektronikk -og det er ikke bare lyd i bil som er min hobby men også hjemme...

men koselig at du er blitt sånn ekspert på disse siste årene

Det jeg også mener at med tanken på hva en kondis koster så er det mye bedre å kjøpe en extra batteri. De eneste gangene en kondis fungerte som en hørbær forbedring var i 90 årene da vi bare hadde elendige baterier med en stor indre mostand. Moderne baterier er langt mye bedre nå, i tilleg så har også moderne strømsforsyninger en annen hastighet (switch frekvens) som er mer effektive.

En ting det ikke blir nevnt forresten er det faktum at de fleste kkondensatorer har en max påtryk spenning på 24 volt... istedenfor 16volt som ville vært mye bedre -men langt ifra så fysisk stor og imponerende...Men hva er viktig ved dette? dette kalles RC tids konstant=teta, som i korte trekk henger sammen med tiden det tar å ladde opp/ned kondensatoren og kurven for oppladning/utladning er en eksponetial kurve og den stigger fortest /raskere til 60% av max påtrykt spenning... den resterende 40% er seint og siden det er en exponetial kurve så vil ALDRI laddes den opp til 100%... så, om du bruker en 24 volts kondis så vil den faktisk forbruke mer strøm enn en kondis på 16volt også selv om anlegget er AV... om jeg noen gang skulle burdert et kondis på den siden av strømsforsyningen hadde det blitt flere mange små kondiser i parallel og på 16volt...

Det er også laget grafer med forklaring på hvordan det er målt og hva som er målt.... og enda en gang: tidskonstanten som visses i grafene forteller klar og tydelig hvor rask og hvor mye kondisen hjelper... men det krever at man forstår det man leser self og det hjelper ikke noe som helt om du ikke vil forstå dette heller...

personlig bruker jeg flere små batterier i paralell, da dette gir en extrem lav indre motstand... enda jeg ikke bruker extreme forsterkere eller spesiele skruer men garantert veldig god lyd... vi kunne ha koblet en kondis i mitt system og prøvd hvor mye den mirakel kondis hadde hjulpet her... men self mange kvakksalvere som mener at de vet bedre om mitt system...

**Erik André** · 19-02-2009, 14:20

Originally posted by matador View Post

jeg har prøvd det engen, derfor har jeg alltid ment det samme om kondiser og "desverre" i tilleg så forstår jeg meget godt hvordan den fungerer teoretisk i en kompleks krets. Greie er bare at uansett hva det er så vil jo alltid være andre som mener noe annet

Det er for mange som mener og tror uten å forstå hvorfor og sammenheng, men jeg trenger ikke overvisse det som andre berømheter allrede sier. Jeg ble dritt lei av å nevne det samme hver gang EA. Men helt ærlig det er bare å bruke pengene sine som man selv ønsker -gjør meg ingenting...

men her har du en klar indikasjon om hva folk som virkelig kan dette bedre enn deg og meg mener om saken...

ellers jeg tror at de karene har både skrud og drivet lengre med bilstereo/lyd enn deg EA... og hvis du mente meg så har jeg drivet med det mye lengre enn deg med bilstereo og elektronikk -og det er ikke bare lyd i bil som er min hobby men også hjemme...

men koselig at du er blitt sånn ekspert på disse siste årene

Har hørt dette før, at du har drevet på så jævlig mye lenger enn meg.. kommentaren fra Bergene var vel at jeg gikk i bleier når du vant din første nasca konkuranse.
Jeg har nå drevet med lyd i bil siden 1990-1991 engang og frem til nå, de siste årene jeg har vist meg frem. At jeg valgte å holde på med lyd for meg selv i så mange år har ikke noe med hva jeg har skaffet meg av erfaring opp mellom. Selv om kunnskaps nivået har eksplodert nå i det siste.

Det jeg også mener at med tanken på hva en kondis koster så er det mye bedre å kjøpe en extra batteri. De eneste gangene en kondis fungerte som en hørbær forbedring var i 90 årene da vi bare hadde elendige baterier med en stor indre mostand. Moderne baterier er langt mye bedre nå, i tilleg så har også moderne strømsforsyninger en annen hastighet (switch frekvens) som er mer effektive.

Moderne strømforsyninger du nevner her gjør så en kondensator (kondis er forøvring hvor lenge man klarer å holde ut i f.eks løping) blir som du sier ubruklige, men som jeg skrev over testet jeg den på en forsterker som har en gammel teknologi, jeg forstår hvorfor den ikke er videreutviklet.. fordi den fungerer. Her fungerer det med en kondensator.. jeg hørte nå ihvertfall forskjell.

En ting det ikke blir nevnt forresten er det faktum at de fleste kkondensatorer har en max påtryk spenning på 24 volt... istedenfor 16volt som ville vært mye bedre -men langt ifra så fysisk stor og imponerende...Men hva er viktig ved dette? dette kalles RC tids konstant=teta, som i korte trekk henger sammen med tiden det tar å ladde opp/ned kondensatoren og kurven for oppladning/utladning er en eksponetial kurve og den stigger fortest /raskere til 60% av max påtrykt spenning... den resterende 40% er seint og siden det er en exponetial kurve så vil ALDRI laddes den opp til 100%... så, om du bruker en 24 volts kondis så vil den faktisk forbruke mer strøm enn en kondis på 16volt også selv om anlegget er AV... om jeg noen gang skulle burdert et kondis på den siden av strømsforsyningen hadde det blitt flere mange små kondiser i parallel og på 16volt...

lurer bare på hva du mener med forbruk av strøm her? Har du en billig biltema kondensator som er tørka ut skjønner jeg at den har et strømforbruk, men de stinger sakene jeg hadde målte 12.4volt de, 3 timer etter jeg demonterte de.. måtte da ta av toppen når jeg testet dette siden toppen har en innebygd utladnings krets montert.

Det er også laget grafer med forklaring på hvordan det er målt og hva som er målt.... og enda en gang: tidskonstanten som visses i grafene forteller klar og tydelig hvor rask og hvor mye kondisen hjelper... men det krever at man forstår det man leser self og det hjelper ikke noe som helt om du ikke vil forstå dette heller...

Ikke det at jeg ikke vil forstå James, men når jeg har gjort meg en erfaring så stoler jeg faktisk på denne nok til å stå for det. Jeg juger ikke når jeg sier jeg har opplevd forbedring, hvis du tror det fordi teoriene dine sier noe annet så skal du få lov til det.

personlig bruker jeg flere små batterier i paralell, da dette gir en extrem lav indre motstand... enda jeg ikke bruker extreme forsterkere eller spesiele skruer men garantert veldig god lyd... vi kunne ha koblet en kondis i mitt system og prøvd hvor mye den mirakel kondis hadde hjulpet her... men self mange kvakksalvere som mener at de vet bedre om mitt system...

Jeg bruker heller ikke kondensatorer og jeg har strømsterke forsterkere som krever litt strøm, men disse har nyere teknologi i seg enn den gamle vrx blokka og jeg kjører alt i 4ohm i dag og ikke i 1ohm som vrx blokka fikk jobbe med. Jeg er helt med på hva du mener og jeg ville nok ikke ha hørt forskjell på anlegget mitt i dag med og uten kondensator. Men at det er forbedrings potensiale i eldre forsterkere med kondensator er det i mine øyne liten tvil om.
En tanke er alle sier har du 3000kr så kjøp et batteri, helt enig.. Har du 6000kr så kjøp to batterier.. men har du 30 000kr så vil jeg påstå at 10 batterier blir tullete.. du nevnte selv vekt økning av bil som et teit tillegg for hva kondensator er godt for (dvs du copy/paste).. med 10 batterier blir i hvertfall bilen min ukjørbar.

Hva spessielle skruer har med saken å gjøre vet nok bare du, men for meg så virker det som negativ EMMA omtale siden Engen bruker snakeeyes fordi han skal stille i master og få bonus poeng for at anlegget hans blir vanskligere å stjele, dette har da ikke noe med lyd å gjøre. Dette vet du og det vet jeg, men emma handler faktisk om installasjon også. Om man ikke ønsker å stille mot dette har man da klasser som advanced der alle kan stille. Der får man poeng for sikker montering og om anlegget ser ferdig montert ut. EMMA handler tross alt litt om at ikke vi skal ha bilbomber kjørende rundt på veiene så dette forblir et minste krav.

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