Car Audio Capacitor vs Battery, Explained In Detail

Most car owners want to upgrade their car audio with a high-end system however, they hesitate to make any updates considering the possible reduced power performance. Usually, it’s too late as car owners find their headlights dimming or their radios not working the way they ought to work after an upgrade. Are these problems about car audio capacitor vs battery or is there something you may have overlooked? Let’s find out as we venture into car audio capacitors and other power supplies.  


What does a car audio capacitor do?

Car audio capacitor info:

Capacitors are capable of storing power from the battery and then release this power to the amp when there is an increase in power demands to produce consistent bass. Capacitors are buffer zones as these are found between the amp and the electrical components of your car. Car audio capacitors will keep your headlights on, prevent dimming even when your car stereo system is in full blast.

Capacitor uses

When it comes to car battery cap or capacitors, these are large capacitors which are also known as stiffening caps. These components will keep your lights at the brightest setting even when your radio is playing full bass sounds. A capacitor provides power to the amp.

A capacitor will prevent audio from changing and deteriorating in the case of an under-voltage but this does not enhance sounds. Capacitors support the amp by providing power in very short bursts and will not enhance sounds but are necessary for an amp to produce the best output.    

Related: Car Speakers Crackling

Capacitor vs battery car audio

A capacitor is a small electronic component that stores power while a battery for a car store large amounts of power to be distributed to the different car systems. Both capacitors and batteries may store power but the amount or capacity varies.

Capacitors store potential energy inside an electric field while a battery stores potential energy chemically. Because of the energy kept in chemical form, batteries can store denser energy and are capable of keeping the same electrical energy amounts as a tiny capacitor.

The way energy is stored gives you an idea as to how energy is released. When it comes to capacitors, these are faster than batteries and thus offer a better advantage, especially when powering your car audio system.

Finally, the cost should also be considered when comparing a capacitor with a car battery. Purchasing a car battery or another car battery is worth the investment compared to just installing a capacitor. Car owners who have just spent money on a new and updated car audio system will likely rely on a second battery to power their system more efficiently.

Consider the pros and cons of using a car audio capacitor


  • There will always be an instant supply of high voltage power if ever you need to use one.
  • You can avoid dimming headlights with a capacitor.
  • Capacitors will charge quicker compared to car batteries.
  • Capacitors will help avoid voltage drops because these are usually placed near the amps.


  • Capacitors are expensive than batteries although it’s clear that these two perform the same tasks.
  • Capacitors offer a lower-density storage option, these are larger and can be harder to keep in a small vehicle. A car with very little space won’t handle large capacitors.
  • Capacitors add strain to your system because it’s another component that the alternator charges.
  • Capacitors may also affect the regular function of a car audio system as this mostly competes with an amplifier in terms of power. A capacitor will hog all the power until it's fully charged and because of this, it can cause problems with the sound system.
  • Capacitors may take away power going to the subwoofer resulting in poor bass performance.
  • You need a technician to install capacitors to your car’s electrical system while you can DIY battery installation especially if you have basic car electrical system know-how. There is a good chance that there’s going to be some problems if you start tinkering with your car’s system if you are not that experienced.

Check out the pros and cons of using a 2nd car battery


  • A second battery is one of the most common techniques to boost a car’s upgraded audio system. Getting a 2nd car battery is far cheaper than using a capacitor.
  • A car battery is a dense energy-storing device that needs less space compared to a capacitor. Take note that both provide similar amounts of electrical energy.
  • A second battery will not just reduce dimming headlights problems as well as problems with other electrical components but will resolve these completely.
  • You can easily buy car batteries anywhere and are available in different sizes and voltages.
  • You can rely on a second battery option as it’s a permanent solution to your car radio electrical needs.
  • You can use the second battery to power other electrical devices in your car.


  • Not all car batteries are created the same. Beware of cheap batteries that can leak and corrode.
  • Charging a second battery can also affect your engine.

How to charge a car audio capacitor?

You must first charge a capacitor before installing it in your system for the first time. It's easy to charge a capacitor but there are techniques to make charging times faster and more efficient.

Remember when charging a capacitor:

Wire the positive terminal of the capacitor to the positive terminal of your car battery. There must be a resistor in between the two terminals. The resistor adds extra load to your circuit to charge the capacitor.

Wire the negative terminal of the capacitor to a ground chassis. Do not place it near or at the same area where the amplifier is located.

You can charge a capacitor to its maximum battery volt levels. A 12-volt battery can charge your capacitor up to 12-volts only and your capacitor can be 1F to 18F. 2F to 5F would be enough for regular sound systems.

How to charge a car capacitor? You must have the following: a power wire (a wire that's similar in size to your audio system wire), wire crimpers or strippers, connectors, pliers, and a memory saver.

Updated capacitors will have a charging device which is made up of a charging plate equipped with4 wires and a resistor. Two of these wires will connect to the positive and the negative points of the capacitor. A positive wire will connect to the positive terminal of the car battery and a second wire will connect to the car chassis ground. Never connect the negative point to the car audio system ground.

Here are the steps on how to charge a capacitor with a battery

  1. Park your car on even ground and activate the parking brake mechanism.
  2. Install the memory saver. This device will save all your settings including car audio settings so your radio will work after you’re done. If you don’t install a memory saver, you need to input a car radio code on your radio for it to work. You need a memory saver if you’re using a battery and capacitor.
  3. Remove the ground wire from your car battery with the negative cable of the battery. As you start removing the positive terminal wire, you may feel a short as you hold the vehicle.
  4. Get the wire for the battery’s positive connection. This wire must have no fuse as this will blow up when you have completed the connection.
  5. Install the connectors on the wires.
  6. Start connecting the positive end of the capacitor to your car audio system. Afterward, mount the device on the vehicle.
  7. Connect the negative end of the capacitor to the ground but be sure to avoid connecting it near the amplifier.

The capacitor is now connected to the car battery. How long does it take to charge a capacitor? It will be ready and charged to full in just a few minutes.

How to tell if a car audio capacitor is bad?

Just like any other electrical component, car audio capacitors can eventually become bad. Once your capacitor acts up, it won’t be able to stabilize the voltage in your vehicle. Electrical issues such as car audio problems and dimming headlights may occur more frequently.

Why do capacitors fail? Typically, a car audio capacitor will last many years. This is a solid-state electrical component made of ceramics and thus, it can survive constant vibration and extreme weather conditions. However, using a capacitor for longer periods can cause failure. Mechanical stress and prolonged exposure to extreme weather and temperatures can lead to failure as well.

All capacitors have a Working Voltage Direct Current or WVDC rating. This means that if the capacitor has exceeded this value, it will soon fail.

There are also supercapacitors that claim to last a long time however, these may last longer but will eventually fail when exposed to the elements. Experts measured capacitor failure according to the number of times the component was charged and discharged and this may be from 100,000 to a million charge cycles.

But is there a way to tell early that your audio capacitors are starting to go bad? Here are some symptoms of bad capacitors in the amplifier. It may be time to charge your capacitor or it’s time to replace it.

  • Your headlights are starting to flicker and dim more often. You may even notice that the headlights are failing especially when you need them, at night. Also, the only time that the lights work is when you start the engine.

Although there are many possible causes of your headlights dimming but consider that an old stereo capacitor may be the culprit.

  • If your car radio is starting to act up, audio can’t be heard from your new speakers, assume that your capacitor could be the reason.
  • Stiffening capacitor car audio.
  • If all other electrical components are failing like your amplifier, car TV, and other devices installed in your vehicle.

Have your car audio capacitor checked if you notice any of these symptoms. Also, it's best to use quality components and not cheap, questionable ones and have them installed by a professional.


Here are the most frequently asked questions about car audio capacitors vs batteries.

  • How to choose a capacitor for car audio?
    You should place 1 Farad of capacitance = 1,000 watts RMS of your system's total power. When using a larger value farad capacitor, there is no penalty and many users see awesome results with a 2-3 Farads of capacitance = 1,000 watts RMS. If you’re unsure about these values, consider the help of a professional installer.

  • How long will car audio capacitors last?
    Audio capacitors for cars can last from 2 to 20 years. The lifespan depends on the make of your capacitor, the car's environmental paly, and other significant factors. If you're wondering about capacitor vs battery car audio, capacitors may last only a few years (depending on their use) compared to car audio batteries.

  • What will bad capacitors sound like?
    Bad or failing capacitors will sound dull, midrange, and even lifeless. You will easily notice that the capacitors are failing when your car audio speakers are no longer working as expected.

  • Should you use a cap for your car audio?
    Capacitors are common in electronic circuitry as they can block current directly but will allow any alternating currents to pass through. When capacitors are in analog filter systems, these can enhance the output of the device's power supply. These can also help tune radios so these can take different frequencies.

Wrap Up

When you’re considering whether car audio capacitor vs battery for a new car audio system, it would be wise to invest in a quality capacitor but a more stable and less complicated power supply is a car battery. If you decide to go with a capacitor, always have it professionally installed to avoid any problems in the future. Don’t use any car audio capacitor troubleshooting steps unless you know what you’re doing.

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