Car Audio Capacitor Vs. Battery

If you love listening to music at its best while driving, then it is highly likely that you would want to amp up the audio system of your car with crossovers, amplifiers, and subwoofers. However, installing these can reduce the efficiency of the other electrical elements of your vehicle. So, to resolve this, you will need a capacitor or a secondary battery for your car.

To make that kind of an informed decision, you need to tally the advantages of the two together. Here’s how:

  • Capacitor-
    • Acts as a buffer
    • Provides rapid short bursts of charge
    • Is lightweight and has an LED display
  • Battery-
    • Has a more massive power reserve
    • Lasts longer than a capacitor
    • Is affordable

Having to choose between an audio capacitor and a secondary battery can be quite the challenge. However, it becomes easier when you have a better understanding of the two.

What Is an Audio Capacitor?

In simple words, a capacitor is a device that stores electricity. It is usually rectangular or cylindrical. The device is capable of rapidly charging and discharging energy.

However, it should not be confused as a source of power. The capacitor acts more like a buffer. It temporarily stores the electrical charges.

Therefore, whenever there is a sudden demand for energy, the capacitor quickly steps in and stabilizes the voltage, thereby preventing other units like your headlights from dimming because your amplifier is consuming more power.


Advantages of Using an Audio Capacitor

  • LED display – This is one of the convenient features. The audio capacitor has an illuminated LED display screen that shows you the voltage flowing through it. With this, you will know if the voltage is too high or too low at any given time.
  • Quick charging – A majority of the available capacitors are of 1-10 Farad. They can charge quickly, making them perfect for use whenever there is a sudden demand for energy.
  • Lightweight – Even when you take a visual inspection of a capacitor, you can see that it is compact, lightweight, and can fit almost anywhere.
  • Audible tone – It has an audible tone that notifies you whenever there is a change in the voltage or if the polarity has reversed.
  • Surge protection – A capacitor has to frequently deal with the constant rise and fall of high voltage. So, to protect it from getting damaged when the voltage is too high, there is a surge protection unit in the device.
  • Fine finish – Capacitors are available with a polished look. They come in black, chrome, and aluminum. This feature makes them blend effortlessly with the décor of your car.

Disadvantages of Using an Audio Capacitor

  • Complicated installation – Unless you have a fair amount of technical background, plugging in an audio capacitor can be very challenging. In fact, if you make any mistakes during installation, it can cause severe damage to both the capacitor and your audio system.
  • Costly – The price of an audio capacitor is more than the cost of both purchasing and installing a secondary battery.
  • Adds strain – Every time the capacitor needs to draw power, it adds more stress to the alternator of your car.
  • Size – Although most of the capacitors are compact in size, there are a few models that are large and have molded irregular shapes. It makes them less compatible with your car.


What is a Battery?

A battery is a source of electrical energy that stores the charge more permanently than a capacitor. It increases the amperage reserve of the system. Your car’s battery is designed to cater to the electrical needs of the units installed in it.

However, when you install more gadgets to your music system, it demands more energy. For this, you can either upgrade the factory-installed battery or, you can invest in getting a secondary battery for your primary.

However, installing a secondary battery is more tedious than upgrading the factory-installed battery. But, if you look at it in the interest of saving some money, this is the better option.

Advantages of Having a Secondary Battery

  • Ample power supply – we have already established that the more sophisticated your audio system is, the more power supply it demands. Unlike the capacitor, your secondary battery has a surplus reserve of electrical charge that can last for an extended period of time.
  • Affordable – Both the battery and the capacitor perform the same action, and yet, there is a huge difference in their price range. A secondary battery is much cheaper and more affordable than a capacitor.
  • Power source – Having an additional source of power reduces the burden on your primary battery. It handles the electrical demand of your amplifier, and it can also assist in keeping the car lights steady.

Disadvantages of Having a Secondary Battery

  • Accidental leakage – A battery reserves the electrical charge in chemical form. Because of this, it needs to be handled with care at all times. A little mishap can cause it to leak on other devices.
  • Additional strain – The secondary battery recharges itself when the engine of your car is running. This can add more pressure to the alternator, thereby adding unnecessary stress to the engine.

Difference Between Capacitor and Battery

Although a capacitor and a battery serve the same purpose of storing charge, there are a few differences between them, especially in terms of their function and design.

  • Design – The manner in which charge is stored in a device affects their discharge rate. The denser the form, the slower is the rate of discharge. A capacitor stores the potential energy in the form of an electric field while the battery stores it as chemicals.
  • Function – Despite its smaller size, a capacitor can hold the same amount of charge as a battery can. However, it disperses the charge a lot quicker than a battery.
  • Cost – After spending a large amount of money on upgrading your music system, you would like to go for an energy source that is more budget-friendly. In this case, getting an extra battery is more reasonable than buying a capacitor.

Capacitor or Battery: When Do You Use Them?

After knowing the pros and cons of both the capacitor and battery, we know that having one or the other is absolutely necessary when you upgrade your car.

Also, early indications like glitches in the bass of your audio system, dimming of your car lights, or even your windows slowly rolling up and down can help you understand that there is a shortage of electrical supply.

So, the question arises, how do you make the smart decision of choosing the right one? Here are a few pointers.

·      Upgrading the music system

Instruments like subwoofers and amplifiers require an instant power supply to reach that acoustical punch in the music. This demand can only be fulfilled by the capacitor.

Whenever there is a sudden need for energy, the capacitor can provide electrical charges in quick outbursts. This, on the other hand, isn’t possible by the battery, especially in such a short span of time. Also, if you crank up the music all the way to the top without a capacitor, it can cause some severe damage to the other devices.


·      Headlights dimming

When you notice that your car is sitting idle, but it seems to produce technical issues, it could be because of the alternator. It produces less electricity when the vehicle isn’t moving. This causes a temporary deficiency of charge, which can be fulfilled by the capacitor.

·      Replacing the audio system

On average, the battery uses about 50% of the starting amperage to run the electronic system of the car. This allows the engine to turn on at any given time without experiencing any delay.

And the rest of the charge is used for other miscellaneous consumers like the factory-installed sound system. The battery installed in your car can adequately handle all these units.

However, if you are replacing the original music system with a more powerful version, it can disrupt the electrical balance of the car. So, to have a consistent power supply, adding a secondary backup battery can meet all the energy demands of your vehicle.

How to Identify the Right Capacitor or Battery?

It is always useful to have a working knowledge about your electrical devices as it can come in handy when you’re in search of the right one. Nevertheless, the following information can help you.

As we mentioned earlier, 50% of the battery charge is reserved for the electronic system, and the rest is for audio. Therefore, deduct the percentage for the electronic system.

If you are going for a capacitor, bear in mind that, for every thousand watts RMS, 1-farad capacitance is included. So, you can also go for 2 or 3 Farads.

A battery, on the other hand, is more flexible. You have an array of options you can choose from. However, what you need to focus here is on details such as maintenance and battery replacements.


We have reached the finish line to the never-ending debate of car audio capacitor vs. battery. Remember, both the audio capacitor and battery have their own benefits and drawbacks. So, you have to assess your situation, understand what your car needs, and get the right medicine for your car-audio ailments.

Once you cover the information gap, it becomes pretty easy to make a decision. We hope you find what you need, cheers!