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Should I Add a Car Audio Capacitor or Battery to My Car?

The benefits of beefing up your car’s audio system are so obvious that we often don’t think about the following power challenges.

An upgrade provides cleaner sound and better audio performance. Nevertheless, the increased power demands will leave you asking, which should I add between a car audio capacitor and battery?

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An audio capacitor is useful when you need extra, instant power when playing bass-heavy music. On the other hand, installing a high-end audio system will require an additional battery rather than a capacitor.

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Tip: Understanding the advantages and disadvantages of each power solution is critical before making a choice. 

When installing a capacitor to protect a large amplifier and subwoofers producing loud bass, you should choose a capacitor that can store at least twice the energy of your amplifier’s peak power output.

So, if you have a 1,000-watt amplifier, you’ll need a 2F capacitor. The excellent capacitors I can recommend are the Planet Audio PC series.

In the article below, I will show you both solutions side by side and help you decide when you need one or the other. After all, you wouldn’t want to install a battery and realize you need a capacitor and vice versa. 

Is a Capacitor Better Than a Battery?

What Does a Car Audio Capacitor Do?

A capacitor is an electronic component that takes and stores energy to release during peak times.

In the case of a car audio capacitor, this device will relay the extra current to the amplifier when it needs a boost when playing bass-heavy or loud music. 

Planet Audio PC10F 10 Farad Car Capacitor for Energy Storage to Enhance Bass Demand from Audio System

Therefore, the amp will not draw energy from the car’s electrical systems, which would cause headlights to dim or windows to stick when playing music. The capacitor buffers or filters sudden circuit voltage changes, smoothing out the audio signal.

Note that a car audio capacitor does not add extra power to your system to improve the sound. Instead, its work is to support the amplifier by giving it the energy it needs in short bursts and preventing the deterioration of sound quality. 

What Does a Car Audio Battery Do?

A car audio battery increases your car’s power and prevents a situation when you have a dead battery due to a powerful car audio system.

The extra battery will feed the amplifier, and it works at full capacity since it stores power better than a capacitor. 

After adding a high-draw amplifier, it’s necessary to have a battery upgrade or a secondary battery. The same case applies when you want to upgrade your stock audio system with a high-end aftermarket system.

Adding a battery reduces strain on the factory power and your charging system. It prevents dimming headlights or a dead battery when running your audio system for hours with the engine off.

Is a Capacitor Better Than a Battery?

A capacitor and a battery fulfill the same goals, but their workings are inherently different.

  • Firstly, a capacitor stores energy using an electrical field while a battery stores its potential energy in chemical form.

Because a battery stores energy in chemical form, it acts as a low-resistance electrochemical voltage source to store large energy reserves. Hence, it can deliver substantial power while only expending a small amount of its reserve chemical energy.

  • On the other hand, a capacitor charges any voltage up to its max rating. 

Still, it can release high amounts of energy. But unlike a car battery, it starts to discharge as soon as it starts to supply current.

A capacitor comes in handy when you want to supply a brief, high-current load to the amplifier. It is better than a battery when it comes to the speed it powers your car’s audio system.

What Are the Pros and Cons of a Capacitor Compared to a Battery?

Pros of a Car Audio Capacitor

  • Have incredible power output when you need an instant high voltage power supply for a short moment
  • Charge quicker than a battery
  • Avoid voltage drops since it sits next to the amplifier.
  • Prevent dimming headlights
  • A high working voltage protects against current surges.
  • Blend well with other accessories owing to attractive black, chromium, and aluminum finishes

Planet Audio PCBLK2.0 – 2 Farad Car Capacitor For Energy Storage To Enhance Bass Demand From Audio System

Cons of a Car Audio Capacitor

  • Perform the same function as batteries but are more expensive
  • Require more technical knowledge to install than a car battery.
  • Quite large in comparison to their energy storage capacity. Its size can also limit the location of installation.
  • Put an extra load on the system since needing an alternator to charge.
  • A cap competes for power with the amplifier until it’s fully charged. In this case, it can prevent the audio system from working at its full potential.
  • Discharge quite fast.

Pros of a Car Audio Battery

  • Come in a variety of sizes and are easy to find
  • Cheaper to buy
  • Simple to install
  • Require less installation space. The amount of energy a battery stores is higher than a capacitor, but it’s significantly smaller than a capacitor.
  • Apart from solving the issue with dimming headlights, provide a solution to other power issues. As such, it can be the permanent powerhouse that you need.
  • A secondary battery can boost power when upgrading to a powerful car audio system. It can also provide extra power for a stationary car, like camping or RVing.

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Cons of a Car Audio Battery

  • Cheap secondary batteries tend to leak their chemical components onto other car parts, causing undue damage.
  • Like a capacitor, an additional battery also needs an alternator to charge. Thus, it will overwhelm your system.

When Do I Need a Capacitor for My Amp?

A power shortage is the number one apparent reason for needing either a capacitor or a battery.

However, there are specific times that a capacitor is more advantageous than a car audio battery. 

Listening to Bass-Heavy Music

If you love punching up the bass in music genres with lots of low-frequency signals, there will be peaks and transients in the songs.

Your amp and subwoofer will need high amounts of extra power for brief moments to handle the peaks and transients. 

An audio capacitor comes in handy to supply the needed energy super fast and balance the voltage. Unfortunately, a battery cannot fulfill the same need at the speed of the capacitor. 

When Electronic Accessories are Acting Up

If your electrical system has no backup reserve capacity, some functions may act abnormally slow when listening to music. It’s the reason why headlights dim every time the car is idle.

This situation happens since the alternator is not producing enough current for the accessories.

Planet Audio PC10F 10 Farad Car Capacitor for Energy Storage to Enhance Bass Demand from Audio System

A capacitor stabilizes the voltage and keeps the functions performing at the same voltage level. Hence, it can meet high voltage needs when your car needs it most.

Removing Signal Noise

A capacitor flows direct current (DC) and blocks alternating current (AC). 

Acting as an open circuit for AC power blocks the signal noise in high-frequency DC power, creating a clear signal. 

When Should I Use an Extra Battery in a Car?

A capacitor has its limits and cannot fulfill the needs that a battery can attain. Here are some of the cases when you need an extra battery. 

Installing a High-End Aftermarket Audio System

Your factory car battery provides enough amperage to start the engine and operate the electrical accessories in your vehicle.

However, adding a powerful audio system stresses the battery, so installing a secondary battery will allow you to run your sound system without draining the primary battery and igniting the engine. 

Using Your Car Stereo With the Engine Off

An extra power reserve is essential if you run the stereo for extended periods without turning on the engine.

It also allows you to run other accessories like the cabin lights in a camping site or car audio competitions without draining the main battery. 

Can A Car Audio Capacitor Drain the Battery?

A car audio capacitor set correctly will not drain the battery.

Nevertheless, if you’re operating a capacitor with caps or third terminals above it, you will need to turn the caps off manually. Otherwise, the capacitor will drain the battery when left to run for hours on end.

If the cause of a drained battery is the capacitor, it’s best to counter-check all its components and ensure you turn them off manually.

However, other things like a faulty accessory or defective alternator could also cause a drained battery. Thus, it’s better to check them off your list too.


Choosing between a capacitor vs. a battery comes down to the purpose you want to fulfill.

A capacitor is suitable for small bouts of power at audio peaks, whereas a battery is ideal for solving voltage drops affecting your stereo’s performance.

So, are you ready to pick from one of these power solutions? 

Now, you’re in the know!