Why Car Audio Capacitors Aren't Worth The Money

Car Audio Capacitors

In my experiences, many newbies think they need a capacitor installed along with their amplifier and subwoofers because of the reason that a capacitor will provide power when the amp needs it.

Here's the problem: When bass is playing, the amp always needs power, and whatever "extra" power it needs will be sucked out of your capacitor in a few seconds max. After you have discharged the capacitor due to heavy power draw, the capacitor will need to recharge.

How does it recharge?

Well, the capacitor sits in between your alternator/battery and your amplifier. Once the capacitor is discharged, it will attempt to charge itself by drawing power from your electrical system.

The power that could just pass from your electrical system directly to your amplifier now has to pass through a capacitor before it reaches the amplifier. Then, once the amplifier needs power again, the vicious cycle starts all over.

Most common car audio capacitors are rated at 1 farad, while I've seen some reach as high as 5, 10, 20, and higher. No matter how high the rating, a capacitor will still hamper performance.

capacitors cannot supply the needed current

This is because capacitors cannot supply the needed current for any extended duration of time to a high power amplifier. When your amplifier needs current, it will suck the capacitor dry in a few seconds (usually less), leaving your capacitor to call on your electrical system to charge up.

See where I'm going now? If a capacitor can only hold a charge for a few seconds, while drawing substantial amounts of current from your electrical system in an attempt to charge back up, all while delaying power the amplifier, then what is the point? There is none. What makes that setup better than giving your amplifier direct access to the alternator/battery?

In comparison, imagine two of the same cars driving in two separate. One lane is smooth to the finish and the other lane has a speed bump. Everything constant, the car with the smooth lane will reach its destination before the car in the speed bump lane.

Capacitors are known in the car audio comity as a marketing ploy

Capacitors are known in the car audio comity as a marketing ploy to make people think they need something, when in reality, they really don't. Take your money and invest it in a second battery. A capacitor these days runs between $50-$80. Add a few more dollars and you can get a second battery, which will supply your amplifier with much more power than a capacitor ever could, all while not straining your electrical system.

A Kinetik HC600 is a prime example of a supplementary, inexpensive battery and some searching puts it in the $80-$110 range.

And for the guys who insist that capacitors work, that's probably because they probably don't have large amplifiers. Here's a really good explanation as to why capacitors may "work" for them.

I say "work" because people say capacitors "work" based on the fact that their headlights aren't dimming as much. This article is meant for people with larger systems, say over 1000W RMS at the least.