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Published Apr. 14, 2020

You can have the loudest car audio system in the world in your car, but without a high-quality car audio capacitor, it may damage your vehicle. Everything working together can dim the lights, drain power from the battery, or hurt the alternator. However, a premium car audio capacitor can reduce any potential damaging impacts to your car as you drive with the bass cranked up.

Acting as a second power supply for your car, a car audio capacitor or stiffening capacitor is basically a smaller version of your car’s battery and stores energy for other electrical components, such as the lights or amplifier. To make it a bit easier to find the best capacitor, we’ve listed a few of the best in our guide below.

The Best Car Audio Capacitor

For anyone who wants to crank up the volume and get that bass pumping, the 5.0 Farad Digital Power Capacity is impressive. It comes with a powerful five farads to power just about any system you can imagine. It also has a blue digital display to let you know how much charge it has left.

It’s protected by a durable aluminum casing, plus it looks pretty cool as well. The canister is equipped with an electronic polarity protection circuit. An over-voltage protection circuit ensures your speaker system gets maximum performance and remains reliable.

Key Features
  • Five-farad system
  • Features capacitance ± 5%, 20-24 volt surge, 105oC w/DC 12 to 24 volt
Specification
  • Brand Pyle
  • Model PLCAPE50
  • Weight 5.2 pounds
PROS

Powerful

Lightweight

Easy-to-read screen

CONS

Annoying flashing light

May not come with installation hardware

Fragile terminals

Rockville’s four-farad capacitor is built with 12-volt stiffening technology, plus it comes with 24 volts of surge power. The canister also comes with a negative polarity feature that will alert you of any potential issues.

It features a lucite encapsulated display screen complete with red LED text that displays voltage meters when voltage drops or rises, while a blue LED light alerts you to its charger and discharge meter. As a bonus, the kit comes with lucite mounting brackets, plus a hardware and charging resistor with instructions for a much more simple installation.

Key Features
  • Four-farad capacitor
  • 12-volt stiffening technology
  • 24-volts of surge power
Specification
  • Brand Rockville
  • Model RXC4D
  • Weight 4.25 pounds
PROS

LED display screen

Multiple farads

Mounting brackets included

CONS

Flashing light can be distracting

May not be able to handle more powerful amps

Planet Audio’s cap has a powerful 20,000,000 of capacitance, 16 VDC of power, and a surge voltage of 24 VDC. It is one of the most powerful and durable capacitors to make our list, plus it’s capable of keeping the headlights on without any dimming or flashing while you pump the bass.

As an added bonus to you and one of the best features of this unit is the audible alert tone. The noise acts as a reverse polarity warning and will also let you know of a possible voltage overload or a low battery. It also comes with a three-digit, bright blue LED voltage meter with an easy-to-read layout of what’s going on inside the capacitor.

Key Features
  • 16 VDC of power
  • Capacitance of 20,000,000
  • Surge voltage of 24
Specification
  • Brand Planet Audio
  • Model PC20F
  • Weight 4.41 pounds
PROS

Large and robust

20 farads

LED display

CONS

Beeps when the car is turned on

Fragile casing

Not compatible with zero gauge wire

Belva’s one-farad power capacitor is small yet powerful. One of the best parts is you get a complete kit for the price. It’s compatible with four gauge two-channel amplifiers and is capable of handling sound systems up to 1,000 watts RMS. It’s housed inside of a reliable and sturdy aluminum casing, so it’s protected and works flawlessly.

The most surprising thing about it may be its weight. Though it is compact, it actually weighs seven pounds, making it one of the heaviest caps on our list. This doesn’t take away from its functionality but adds a bit of weight to your car. It does have an LED display screen but it is on the smaller side.

Key Features
  • One farad
  • 1,000 watts of RMS
  • Aluminum casing
Specification
  • Brand Belva
  • Model B1DK42BK
  • Weight 7 pounds
PROS

Compact and powerful

LED display

CONS

Heavy

Small screen

Sound Storm’s 3.5-farad car audio capacitor has a working voltage range of 16 VDC with a surge voltage of 24 VDC. Plus, it also has a tolerance percentage of +/- 10 percent. It has a red text display screen so you can read the charge and voltage left in the canister.

It’s designed with chrome-plated posts and includes hardware and mounting brackets to make for an easier installation. It weighs less than four pounds as well.

Key Features
  • 3.5 farads
  • Voltage range of 16 VDC
  • Surge voltage of 24
Specification
  • Brand Sound Storm
  • Model C352
  • Weight 4 pounds
PROS

Robust

Wide tolerance percentage

Lightweight

CONS

Larger than expected

Installation can be difficult due to size

Charging can take up to one minute

The SoundBox 4 Gauge Amp Kit 2.5 Farad Digital Capacitor is a mouthful to say but it’s a wonderful little piece of machinery. It comes with everything you need to install it to your amplifier and includes a one-year manufacturer’s warranty. Plus, it can handle up to 2,500 watts of peak power.

The wires come surrounded in a heat-resistant jacket to ensure they don’t overheat. It is powerful enough to stop your lights from dimming and flashing like a disco nightclub.

Key Features
  • 2.5 farads
  • 2,500 watts of peak power
  • One-year manufacturer warranty
Specification
  • Brand SoundBox
  • Model 5 pounds
  • Weight B07BW67RFK
PROS

Easy to install

Built out of sturdy material

Very powerful

CONS

Terminals are a bit flimsy

Cables may be too short

Weak mounting brackets

This stunning silver-finished audio capacitor from Boss Audio is a great choice for powering your amp. It has a low-level input voltage of 20 volts and a high input of 24 volts. One huge benefit of the cap is its warning tone that lets you know anything wrong with it. It even comes with an LED display screen.

The capacitor charges rather quickly and boosts the power of your amp and speaker system while reducing light flickering. It is easy to install and has a nice look to it.

Key Features
  • Two-farad system
  • Silver finish
  • Low input voltage of 20 volts
  • High input voltage of 24 volts
Specification
  • Brand Boss Audio
  • Model CAP2S
  • Weight 4 pounds
PROS

Easy to install

Looks great

CONS

Not compatible with higher wattage amps

No extra wires included

May require extra charging

Best Car Audio Capacitor Buying Guide & FAQs

If you have a beefy car stereo system with large speakers and a booming subwoofer, then you may need a car audio capacitor. High wattage amplifiers suck a lot of power from your vehicle’s electrical system. When a deep bass note hits, the system may not be able to supply a high current quickly enough to other components of your car. This is what leads to dimming lights or reduced car battery power.

Capacitors use farads to determine the amount of power they contain. For instance, if your amplifier contains 1,000 watts of power, it’s recommended to get a capacitor with one farad to handle the amp.

Benefits of a Car Audio Capacitor

There are several reasons to get a car audio capacitor for your car, truck, SUV, or Jeep. An impressive audio system is great, but when it siphons energy from other other components, your vehicle loses power. A loss of power can drain your car battery, reduce gas mileage, and damage other electrical parts of your car. But a capacitor can prevent the lights from flickering, increase visibility, and improve the performance of your vehicle.

The best car audio capacitor will help you out in a number of ways. While the battery can focus on powering the lights and other components, the capacitor will enhance your audio system. Since the battery doesn’t have to power the speakers or amplifier, it can send power to every necessary thing without a hiccup while the capacitor focuses on powering your audio system. Having fully functioning lights will allow you to focus more on the road.

  • A car audio capacitor will help prevent any unwanted distractions on the road by making sure the car’s headlights stay on when rocking out to heavy bass.
  • A capacitor will help ensure the battery isn’t drained so everything else on your car functions without an issue.
  • With a capacitor powering your amp and speakers, the battery can power other components.
  • A car capacitor will allow your battery to keep the lights on inside your car.
Car audio capacitor and speakers at the side of door

Types of Car Audio Capacitor

There are three main types of audio capacitors and each one functions differently. By choosing from electrolytic, carbon, or hybrid, you can ensure your audio amplifier continuously pumps music while your battery focuses on the lights and alternator. All three work basically the same, but where they differ is in their ability to hold a charge.

  • Electrolytic

An electrolytic car audio capacitor typically has a more rapid charging system. However, they also tend to have less power in their reserve. Electrolytic capacitors will also come in a round canister similar to a soda can. They will come with around one farad for every 1,000 watts of power.

An electrolytic car audio capacitor is the most standard and basic of the three choices. They are small, lightweight, and compact enough to fit easily and simply in your car. It may even be more beneficial to you to install several so ensure your system is powered efficiently and effectively.

  • Carbon

The next type is known as a carbon car audio capacitor. They work in the exact opposite of their electrolytic cousins. Instead, they focus on holding more power inside their core. This way they can divert even more power back to the amplifier when it requires it.

The one downside is they will not be able to recharge as quickly as an electrolytic type. This means they can hold a lot more power at a time but once it’s expended, it will take more time to regain the energy. They do, however, tend to use the same amount of farads as their electrolytic counterparts.

  • Hybrid

If you can’t tell by the name of this capacitor, it is a blend of both the electrolytic type and carbon models. The one downside is they tend to be a bit more expensive, weigh more, and are larger as well.

Instead of the smaller canister style you find in electrolytic capacitors, hybrids are clunky and robust. They are similar in appearance to amplifiers but they contain a lot more power. However, instead of using one farad per 1,000 watts of power, it is recommended to use five farads. They basically function like a second battery for your vehicle but focus on the amplifier.

Features to Look for in Car Audio Capacitor

There are several features of a car audio capacitor you should be aware of. They may appear small in stature, but they make up for it in power and performance. There are three main functions to focus on when considering a car audio capacitor: value rate, surge value, and terminals. Things like voltage protection, charging time, and display are important, but don’t require a lot of explanation. Voltage protection is how the cap is protected when in use. Consider one with protections on the high and low ends of voltage and one with an automatic shutoff. The charging time is how long it takes to charge back up after dispersing energy to the amp, while the display lets you know how much charge is in the cap.

  • Value Rate

The value rate of a car audio cap is perhaps one of the most important factors, as it measures the amount of charge kept in the device in terms of farads. For every 1,000 watts of peak power, you will need around one farad. To make it more simple, the value rate is how many farads are inside the cap.

While a 1,000 watt amp is quite powerful, you can build ones with even more power and bass. If you participate in audio competitions or just want to show off your audio system, consider a capacitor with a few farads. You should see how many watts your amp puts out to determine how many farads you will need.

  • Surge Value

An audio capacitor’s surge value is equally as important as the value rate. The surge value is how much voltage the cap can take before overloading or malfunctioning. Check the DC rating of your alternator and battery and compare it with the cap. You will want to make sure the capacitor’s rating is higher so it provides power to the amp and speaker system.

You will need to be careful when finding the correct voltage rate, however. The capacitor comes with a certain amount and cannot exceed the surge level. If it does, the cap could be damaged beyond repair. The same can be said for a low voltage rating.

  • Terminals

Like an amplifier, an audio car cap will come with several terminals or connections for your audio system. Electrolytic capacitors will generally come with one or two plug-ins due to their small size while larger ones, such as hybrids, can contain more.

You can also buy multiple capacitors if you need to. This will ensure your amp is powered properly and you don’t lose any power when listening to music. If you have any extra terminals leftover after plugging everything in on your amp, they can be used as a distributor block. This will make for a much easier install.

Car audio speakers and capacitor

Tips for Buying and Using Car Audio Capacitor

There are a few things you need to know in order to ensure your car audio capacitor runs smoothly over time. Before you even get it running with your audio system, you should ensure it is properly charged. You also need to make sure it is placed in the proper location so it runs more efficiently.

The good news about most basic car audio caps is they are small and can be placed nearly anywhere in a car, truck, SUV, or Jeep. This means you can put them in the trunk or out of sight or keep them close so you can see how much charge they have left. It’s ultimately up to you.

  • When charging the capacitor for the first time, make sure you do so slowly and monitor it as it charges.
  • You can monitor the charge by using a resistor to limit the speed at which they charge.
  • Place the capacitor near the amplifier for the most amount of power possible.
  • Capacitors have a red positive and a black negative cable; make sure you plug these in correctly.

Best Car Audio Capacitor FAQs

The best car audio capacitor will be one that powers your amplifier quickly. It can be confusing to understand exactly how they work or what a farad is, so we’ve put together a list of questions you may end up asking. Here are a few things to know to better understand your new car audio capacitor.

Q: How do I figure out how many farads the amp needs?

You should start by checking your amplifier. Amps feature watts of peak power and range from a few hundred to a few thousand. You will need around one farad per 1,000 watts of peak power to ensure the amp runs smoothly. If the amp has more watts, then you will need more farads. You can always add more capacitors.

Q: Why does the capacitor come with a resistor?

The resistor is used to slow down the charging rate of the capacitor. If it charges too quickly, it can damage the cap and even weld the terminal connections to the amp. Once the cap is charged, you can remove the resistor until you need it again.

Q: Are capacitors compatible with all amp brands?

Yes. It shouldn’t matter what brand of amplifier you have as long as the capacitor is rated for the correct amount of watts.

Our Top Pick

Our overall choice for best car audio capacitor is the 5.0 Farad Digital Power Capacitor from Pyle. It comes with five farads to keep your amp running smoothly while keeping your lights on as well. It comes with an easy-to-read digital voltage display so you can monitor it on the go. It is protected by a durable aluminum casing and looks great.

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