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Best Car Audio Capacitors: Keep the Bass Pumping and Lights Bright

Keep the bass thumping and the lights from dimming with these high-quality car audio capacitors

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BY/ LAST UPDATED ON September 23, 2020

A loud and bassy car audio system is great, but it can also hinder other parts of your vehicle. An overpowered amplifier can drain the juice from your battery, dim the car’s lights, or strain the alternator. To help alleviate any issues or potential damage, you should hook up a high-quality capacitor. It works like a smaller version of your battery and stores energy to be used for other electronic components, such as the amplifier. Here are the best car audio capacitors to consider for your ride.

Best Overall

Planet Audio 10 Farad Car Capacitor

Summary
The Planet Audio unit comes with a powerful capacitance of 10,000,000, 16 VDC of power, and a surge voltage of 24 VDC.
Pros
It features an audible alert warning to let you know if the cap reaches reverse polarity, a voltage overload, or has a low battery. Plus, it has a three-digit, bright blue LED voltage meter.
Cons
It is not compatible with 0 gauge wire, and the casing surrounding the cap is weak and can fall apart during installation. You may also get an annoying beep from the cap every time you start the vehicle.
Best Value

BOSS Audio Systems CPBK2 2 Farad Capacitor

Summary

This is a 2-farad capacitor that only takes seconds to charge. It features a red, three-digit voltage display that’s easy to read even in the dark.

Pros

Audible alert tones that warn you of low voltage, overvoltage, or reverse polarity. Features remote terminal screws that are easy to hook up for charging or connecting to the car audio amp.

Cons

Its small and compact profile stores less energy. May be inadequate for more powerful amplifiers. The screws are somewhat fragile and can break if overtightened.

Honorable Mention

Sound Storm 3.5 Farad Car Capacitor

Summary
This capacitor is rated at 3.5 farads and has a working voltage range of 16 VDC with a surge voltage of 24 VDC and a tolerance percentage of +/- 10 percent.
Pros
It is fitted with a small red text display screen to let you know the exact measure of charge and voltage in the canister. Plus, durable chrome-plated posts with hardware and mounting brackets make for simple installation.
Cons
Its large size may make things more difficult when installing it in place. It may also take up to a minute to charge the capacitor. Another drawback is you need to purchase wires to properly hook it up.
Best Car Audio Capacitors: Keep the Bass Pumping and Lights Bright

Types of Car Audio Capacitors

Electrolytic

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The main difference in the types of car audio capacitors is in their ability to hold a charge. Electrolytic ones generally have a faster recharge rate but less power in their reserve. An electrolytic capacitor will also, typically, come in a round canister, and it should use one farad (the amount of power they can hold) for every 1,000 watts of power.

Carbon

Carbon car capacitors are the opposite of their electrolytic counterparts. While they are able to hold more power to divert back to the amplifier and the entire audio system, they will not be able to recharge as quickly. Generally, they will use the same amount of farads as electrolytic capacitors.

Hybrid

You can also find a blend of both electrolytic and carbon models, but they may be more expensive and larger. They will look like a smaller version of a vehicle’s amplifier, and the recommendation is to use five farads for every 1,000 watts of power. Consider a hybrid audio capacitor if you are in need of a second battery. 

Car Audio Capacitor Pricing

  • Under $50: In this price range, you will find a good amount of car capacitors that will get the job done. They are distinguished by their number of farads; the higher the farad counts the more expensive the capacitor will be. These will also come with two terminal connectors and a lower amount of voltage.
  • Over $50: In this price range, capacitor pricing varies by the number of farads, terminals, and the voltage. The more of each, the stronger and more durable the capacitor will be.

Key Features

Value Rate

The value rate of a capacitor is one of the most important factors of the component. It measures how much charge the device can keep in it by using farads. The range can vary from two farads to several more. The more powerful your amplifier, the more farads you will need.

Surge Value

The second most important thing about a capacitor is its rated and surge voltage values. You will want to be sure the capacitor has a DC higher than your alternator and battery. However, you will want to be careful when finding the correct voltage rate; a capacitor that exceeds its surge level could be damaged beyond repair, while a low voltage could also cause it to short. 

Terminals

The more terminals the capacitor has the more components you can connect to it. While smaller ones will typically come with two terminals, larger ones will come with more. Extra terminals are also useful if you need to use it as a distributor block, and it will make installing the hardware easier.

Other Considerations

  • Voltage Protection: Look for a capacitor with protection on the high and low ends of voltage. This will ensure the cap lasts for several years. Also, many should come with an automatic shut off. 
  • Charging Time: If a capacitor takes a lengthy time to charge, such as over a minute, consider swapping it out with another one. It can heat up quickly and cause it to burn up and break.
  • Display: A capacitor with an LED display is a great way to monitor the amount of charge inside it.

Best Car Audio Capacitor Reviews & Recommendations

The Planet Audio cap from Boss Audio comes with all sorts of extras to power your audio system. It has a powerful capacitance of 10,000,000, 16 VDC of power, and a surge voltage of 24 VDC. That makes it one of the most robust and durable capacitors on our list, and it’s capable of keeping your headlights bright no matter how loud the music gets.


One of the best features with this unit is its audible alert tone that acts as a reverse polarity warning. It will also let you know of a possible voltage overload or a low battery. The inclusion of its own voltmeter measures the level as well. It’s also equipped with a three-digit, bright blue LED voltage meter, giving you an easy-to-read layout of what’s going on inside the capacitor. 


As far as downsides go, if you have a 0 gauge wire it is not compatible with this capacitor. The casing surrounding the cap is also not strong and can fall apart when installing, but it won’t damage the actual component. You may also get an annoying beep from the cap every time you start the vehicle.

The Boss Audio Systems capacitor is lightweight and compact enough to fit in the smallest places. It can keep up with a high-powered sound system due to the fact that it has a high-level input voltage of 24 volts. In addition, it has a capacitance value of two farads, meaning that it will only take seconds to charge, and thereafter will be ready to power your car audio amplifier.


The unit gives audible tone alerts whenever something’s amiss including instances of overvoltage, low voltage, or reverse voltage. You can also note the capacitor’s voltage on the red, digital voltage display that's easy to read. What's more, the unit is long-lasting thanks to its corrosion- and weather-resistant housing.


While the compact profile makes it blend in seamlessly with your vehicle's upholstery, it stores less energy in comparison to bigger capacitors, and would have to be charged more often. For the same reason, it may not power some larger and higher-powered amplifiers. Also, the terminal screws are rather fragile and can break if overtightened.

While Sound Storm’s capacitor is only rated at 3.5 farads, it holds up to some of the more powerful ones. It has a working voltage range of 16 VDC with a surge voltage of 24 VDC as well. The small capacitor also has a tolerance percentage of +/- 10 percent, giving you a great amount of flexibility with your vehicle’s sound quality and lighting.


It is fitted with a small red text display screen to let you know the exact measures of charge and voltage in the canister. As far as durability goes, the cap is designed with chrome-plated posts with hardware and mounting brackets to make for an easier installation. Altogether, the capacitor is also light. It weighs less than 4 pounds and is available as a two-farad power capacitor as well.


While it may look small, it is actually a bit larger than expected. This may make things more difficult during installation, but it shouldn’t impact the process too much. It also may take up to a minute to charge the capacitor. You should only worry if it takes longer than that. Another drawback is you need to purchase wires to properly hook it up.

Tips

  • The first time you charge a capacitor, make sure to do it slowly. Most capacitors come with a resistor to limit the speed of charging. If you don’t have one you can use a 12-volt automotive light or small LED.
  • To ensure you are getting the most amount of power, make sure the capacitor is placed near the amplifier.
  • Pay close attention when wiring the capacitor up to your vehicle. Similar to batteries, they have a positive red cable and negative black cable.

FAQs

Q: How do I determine the number of farads I need?

A: To figure out exactly how many farads are required to run your audio system, first check your car amplifier. Ones that use less than 2,000 watts only need about one to two farads to successfully power your system. The more power you have, the more farads you will require.

Q: What does the extra terminal on the capacitor do?

A: The extra terminal may be for the voltage meter display. If it is left on for long periods, the battery may be drained. The terminal acts as a remote turn on and off switch to prevent any drainage.

Q: How are capacitors measured?

A: You can measure the energy inside the capacitor by performing a test frequency using 1kHZ or 120Hz.

Final Thoughts

For one of the most powerful and durable car audio capacitors that will leave your lights bright, consider the Planet Audio 10 Farad Car Capacitor

You could select a more budget-friendly option and still keep the bass pumping with the BOSS Audio Systems CPBK2 2 Farad Capacitor.

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