Why Car Audio Capacitors Don't Work

A car audio power Capacitor is a non-powered storage device for electrical power.Sometimes referred to as a cap, power cap or stiffening cap.They come in cylindrical shapes that are three inches in diameter and about a foot long, though rectangular shapes are also available for different technologies.There will be a positive and negative terminal with a third remote turn that can turn on or off the display.They are designed for one thing, to store electrical power.

A car audio power cap works by storing large amounts of electrical power which it can deliver to power hungry components when called upon to do so.They have an advantage over typical lead acid storage batteries because of their low internal resistance.This allows them to deliver a lot of power quickly.The same amount of current can be delivered much faster than a car's charging system.

Current demands can be very large for a car audio power amplifier.This depends on the music being played through the amplifier.Transient peaks are when these currents are needed the most.If the amplifier tries to pull the current from the electrical system, it may cause a drop in voltage.The size of this drop depends on the resistance of the wire from the source to the amplifier.

If you have twenty feet of 8 gauge wire, your amplifier suddenly needs 100 Amps for a bass hit.In this case, the current and the voltage are equal to the resistance.We can see that 8 gauge wire has a resistance of 0.000739 ohms per foot using a power wire resistance table.By the length of the wire, we have to get a total resistance of.01478.That doesn't seem like much, but compared to a vehicle's electrical system it is.Ohm's Law is used to calculate the math.

100 Amps running through a twenty foot run of 8 gauge wire causes the amplifier's voltage to drop.If your vehicle's system is charging at 14 volts, the average range is 13 to 15.You need to know the current draw and wire length in your system.If your amplifier is capable of drawing large currents on a continuous basis, you need to have a large power wire.

What do you mean by that having to do with a car audio powerCapacitor?There are two things.First, a powerCapacitor is placed closer to the amplifier than the battery, so that the voltage drop is going to be less, all other things being equal.Your charging system probably isn't designed to provide large current draws.Your amplifier is going to need the power from the vehicle's battery as well as the alternator.The internal resistance of the battery is much higher than that of a car audio powerCapacitor.It is not an effective means of delivering large amounts of instantaneous current because of the extra internal resistance.The battery is larger than a small tank with a large hose.A large current burst during a music Transient can be delivered with a Capacitor installed.

The diagram shows the Capacitor as a water tank.The water is the electrical energy that a Capacitor stores.The input line comes from the battery.The output line goes to the amplifier.The output line lets the tank drain quickly.If the amplifier tries to pull too much out, the tank will empty and you will have to wait until the battery replenishes it.It's important to make sure your tank is big enough for your amplifier.The "tank size" is measured in Farads.

I don't know.How is that for an answer?Depending on your specific vehicle, car audio amplifier(s) current draw, music type and listening habits, the degree of help a powerCapacitor will give you depends on.

The first thing most people do is dim their headlights.ACapacitor is needed by most car audio enthusiasts with a passing knowledge of electrical systems.Is the headlights dim?You should get a cap.That is a good guess, but not always true and not a guaranteed cure.The powerCapacitor can only do so much.If your electrical system only has a small scratch, it's a good band-aid, but if it is bleeding, you need stitches.There are stitches in the form of an upgraded battery.If the headlights only dim when the engine is running then it's probably not much to worry about.The current draw from the audio system remains the same even though the vehicle is idling.

The accepted rule has been one Farad of capacitance per 1,000 watt of power with a minimum of one.The value was determined by Richard Clark.It doesn't hurt that more is not necessarily better.

If there are no problems with your system, then it probably isn't worth the added expense.I've done vehicles that benefited greatly from caps and others that didn't.The only way to find out is to try it.It's unlikely that a car audio shop will allow you to test drive a powerCapacitor.It is possible to borrow one from a friend that already has one installed.Don't forget to follow the same safety rules for uninstalling and installing aCapacitor as you would for a battery.You can either have an inadequate charging system or a faulty one if installing the powerCapacitor doesn't help with dimming headlights.If the electrical system isn't charging correctly, a qualified mechanic can tell you.They need to check the grounds for the battery, engine block, and power wire.

It is possible to determine if the factory charging system is adequate under ideal conditions.30% of the output rating of your alternator may be available for your audio system.When idling, the rated output will not be available because the output is not constant.The more current the alternator puts out, the faster it spins.The alternator will put out less than its rated current if you use an underdrive pulley on your engine.Under the conditions you will use it, determine the current draw of your audio system.The manufacturer of the amplifier should provide this in the owner's manual.The maximum current draw is used if you crank it to the max.You will probably want to use the "typical" or "with music" rating.If your alternator is rated at 80 Amp, you have 24 Amps available.Current drawing devices like lights and fans are off.Your typical current draw needs to be less than 24 Amps.You'll be pulling additional current from a storage device if it's more than that.Dimming headlights syndrome can be caused by the degree of additional current you need.Small overages can be helped with a Capacitor, while large ones need an upgraded battery and alternator.

You should read the article on car audio Capacitor installation.