Capacitor vs High Output Alternator: Which is Better?




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One of the biggest dilemmas that car audio enthusiasts face is how to provide that extra amp needed to fuel a powerful audio setup.

This is where the choice between a capacitor and a high-output alternator comes into play, but which one is better for the car audio system? Let’s find out. 

Both capacitors and high-output alternators help to prevent voltage drops and ensure consistent power delivery. However, the choice between the two ultimately depends on the specific needs and characteristics of the system. Capacitors provide a quick burst of power, while high-output alternators provide sustained power over a longer time.

Through this article, I will provide some insight into the roles and benefits of both high-output alternators and capacitors. 

Key Takeaways
Understanding the role of each component is crucial. A capacitor provides quick bursts of power during peak demands, while a high-output alternator supplies a consistent power output.
Analyzing your specific needs is vital. The requirements of your car audio system can dictate whether a capacitor, a high-output alternator, or a combination of both is needed.
Costs should be factored in. While capacitors are typically cheaper upfront, a high-output alternator might provide a more long-term solution for high-performance audio systems.
Safety and proper installation are paramount. Whichever option you choose, ensure it is correctly installed to prevent performance issues and potential damage to your car’s electrical system.
There’s no one-size-fits-all answer in the capacitor vs high-output alternator debate. The decision depends on the unique needs of your car audio system and your budget.

Ready to take your car audio system to the next level? Our article on the role of an alternator in a car audio system has all the information you need.

Understanding Capacitors and High-Output Alternators

Before I dive deeper into the comparison between a capacitor and a high-output alternator, it’s crucial to understand what each of these components is, how they work, and their roles in car audio systems.

What is a Capacitor?

A capacitor, in simple terms, is a device that stores electrical energy. It’s like a mini-battery within your car audio system that accumulates power and then swiftly discharges it when your audio system requires an extra boost.

You might be asking, “Why do I need this extra boost?” Here’s why: music isn’t played at a constant volume. It has peaks and valleys.

adding capacitor or high output alternator for car audio

The peaks, especially in music with heavy bass lines, require more power. If this power isn’t available, you can experience dimming lights or even a drop in performance.

There are a few types of capacitors you could choose for your car audio system, each with their own benefits:

#1. Electrolytic Capacitors: These are common in car audio systems due to their high capacitance and voltage capabilities. They are an economical choice and have a long lifespan.

#2. Super Capacitors: Also known as ultra-capacitors, they can store a lot more energy compared to standard capacitors and can deliver a large amount of power in a short period. However, they tend to be more expensive.

#3. Film Capacitors: They are not typically used in car audio systems but are worth mentioning. Film capacitors are known for their stability and low distortion characteristics, making them ideal for high-end home audio systems.

What is a High-Output Alternator?

A high-output alternator, on the other hand, is like the powerhouse of your vehicle.

The alternator’s primary job is to generate electrical power to run your vehicle’s electrical systems and recharge the battery. A standard alternator can handle the electrical load of a regular car – the lights, ignition, electric controls, and the stock stereo.

But when you start adding power-hungry components like high-performance car audio systems, the standard alternator might not cut it.

A high-output alternator is designed to generate more electrical power, ideal for running these high-powered systems. It continues to produce power as long as your engine is running, providing a steady and continuous supply of electricity.

When considering a high-output alternator, there are a few types you might come across:

#1. Standard Alternators: These are typically rated around 65-100 amps and are sufficient for a car with minimal electrical load beyond the factory components.

#2. High-Output Alternators: These are rated anywhere from 200 to 300 amps and are designed for vehicles with significant additional electrical loads, such as high-performance audio systems, additional lighting, or other aftermarket accessories.

#3. Extreme High-Output Alternators: These alternators can deliver 350 amps or more. They are also used in competition vehicles with extremely high-powered audio systems, and the most popular ones are from Mechman.

Capacitor or a High-Output Alternator for Car Audio System: Comparing the Pros and Cons

Now that you understand what capacitors and high-output alternators are and their functions, let’s dig into a more detailed comparison of their advantages and disadvantages in the context of car audio systems.

Benefits of Using a Capacitor for Car Audio

Capacitors offer unique benefits when used in car audio systems. Here’s why you might consider them:

#1. Quick Energy Boosts: Capacitors are designed to provide quick bursts of energy when your amplifier needs it most.

They’re excellent at ensuring your music maintains a consistent quality, even during those bass-heavy peaks that demand a higher power supply.

#2. Preventing Power Drains: If you’ve noticed your lights dimming when the bass hits, that’s a sign your audio system is drawing more power than your car’s electrical system can provide.

A capacitor can prevent these power drains, storing energy and releasing it quickly when required.

#3. Prolonging the Life of the Battery and Alternator: By storing and supplying energy during high-demand periods, capacitors take some strain off your car’s battery and alternator, potentially extending their life.

#4. Cost-Effective: Generally, capacitors are more affordable than high-output alternators, making them a cost-effective solution for boosting your audio system’s performance.

Benefits of Using a High-Output Alternator for Car Audio

High-output alternators also have their advantages:

#1. Continuous Power Supply: Unlike capacitors, which provide short bursts of energy, high-output alternators supply continuous power. They’re ideal for high-performance car audio systems that regularly draw a lot of power.

#2. Higher Power Output: High-output alternators can produce significantly more power than standard ones, making them suitable for vehicles with large, power-demanding audio systems.

#3. Long-Term Solution: High-output alternators are more of a long-term solution. While the upfront cost may be higher, they provide consistent, reliable power over time, which may save you money in the long run.

Can a High-Output Alternator Damage Car’s Electronics?

A common question I often hear is, “Can a high-output alternator damage a car’s electronics?” It’s a valid concern, but in most cases, a high-output alternator won’t cause any harm.

Here’s why: your car’s electronics only use the amount of power they need. Having more power available doesn’t mean your electronics will use more than necessary.

However, proper installation is critical. An incorrectly installed high-output alternator can lead to problems. Therefore, I highly recommend having it installed by a professional.

Also, keep in mind that you may need to upgrade other parts of your electrical system (like cables and fuses) to handle the higher output.

Using a Capacitor and a High-Output Alternator Together

The choice between a capacitor and a high-output alternator isn’t always an either/or situation.

Depending on your specific needs and the requirements of your car audio system, you might find that using both can provide the optimal power solution.

The Benefits of Pairing a Capacitor and High-Output Alternator

Here’s why using both a capacitor and a high-output alternator in tandem can be beneficial:

#1. Continuous and Burst Power: A high-output alternator provides a continuous power supply for your car’s electrical needs, including your high-performance audio system.

The capacitor, on the other hand, can give those quick bursts of power when the music demands it, especially during intense bass lines. Essentially, you’re equipping your system with the best of both sides.

#2. Minimize Power Strains: While the high-output alternator handles the heavy lifting of powering your advanced audio system, the capacitor can step in during peak demands, preventing any power strains on your vehicle’s electrical system with an extremely heavy load from the subwoofer’s amps.

This can be particularly beneficial in preserving the longevity of your car’s battery and the alternator itself.

#3. Improved Audio Performance: Combining a capacitor with a high-output alternator can result in overall improved audio performance. You’ll have the high continuous power output you need for a powerful sound system and a capacitor to provide those quick energy jolts for consistent sound quality.

While using a capacitor and a high-output alternator together can offer these advantages, there are some considerations to keep in mind.

Considerations When Using Both

#1. Increased Costs: Of course, using both a capacitor and a high-output alternator will involve higher costs—not just for the components themselves but potentially for professional installation as well.

#2. Space Constraints: You’ll also need to consider the physical space within your vehicle.

Both these components will need to be installed in your car, so ensure there’s enough room to accommodate them.

#3. Proper Installation: As with any component in your car’s electrical system, proper installation is critical. An incorrectly installed capacitor or alternator can lead to problems down the line, so with these elements, there is no room for error.

Deciding Between a Capacitor and a High-Output Alternator: Factors to Consider

Making the right choice between a capacitor and a high-output alternator can seem tricky. As you already know, both can provide enhanced power for your car audio system, but your specific needs and circumstances will determine which is best for you.

Let’s explore some key factors to help you make an informed decision.

Consider a High-Output Alternator if:

#1. You Have a High-Performance Car Audio System: If your car audio system frequently draws a lot of power—think subwoofers, amplifiers, and high-volume audio—then a high-output alternator could be your best bet for providing the necessary continuous power.

#2. Your Current Alternator Can’t Keep Up: If you notice your battery struggling to keep charged or your lights dimming when the music is playing loud, it could be a sign your current alternator can’t handle the power needs of your audio system.

Upgrading to a high-output alternator could resolve this issue.

Consider a Capacitor if:

#1. You Experience Power Spikes: If your music involves heavy bass or high-power peaks and you notice brief moments where the sound quality drops, but the amplifiers are not extremely powerful, and the alternator charges the battery with no issues, a capacitor could be the solution.

It can provide those quick power jolts to ensure consistent sound quality.

#2. You Want to Prolong Your Battery and Alternator Life: A capacitor can take some strain off your car’s battery and alternator during peak power demands, potentially prolonging their lifespan.

Installation Costs: Capacitor vs High-Output Alternator

Now, let’s talk about costs. The overall expense will depend on several factors, including the specific models chosen, professional installation fees, and potential additional costs for system upgrades.

#1. Capacitor Costs: Capacitor costs are generally the more affordable option, with most within the $50 – $80 range.

However, keep in mind that while a lower upfront cost may be appealing, capacitors might not provide the continuous power needed for more demanding car audio systems.

#2. High-Output Alternator Costs: High-output alternators are more expensive, and the previously mentioned Mechman range between $300 to over $600, depending on the produced amperage.

They are however robust, long-term solutions for high-performance audio systems. Despite the higher initial investment, the reliable, continuous power supply could offer better value in the long run.

Further Reading About Car Alternators

Want to make the most out of your car’s audio system? Learn about the potential need for alternator upgrades in our detailed article about when to upgrade car audio alternators.

Why Am I Hearing Alternator Noise Through Car Speakers

Wondering why you can hear alternator noise through the car speakers? This issue, often known as alternator whine, is surprisingly common among vehicle owners. It’s caused by what’s known as electromagnetic interference (EMI), which the alternator generates, and the audio system subsequently picks up.

To delve deeper into why this occurs and how you can combat it, I invite you to visit our detailed guide on the causes and potential solutions for alternator noise in car speakers.


To wrap things up, let’s highlight a few key points:

#1. Understand the Role of Each Component: A capacitor provides quick bursts of power during peak demands, while a high-output alternator ensures a steady and continuous power supply.

Knowing the specific role of each component is essential in making an informed decision.

#2. Analyze Your Specific Needs: Consider the requirements of your car audio system, and assess whether you’re dealing with power spikes during high-volume music or a consistent demand for high power.

This will help guide your decision towards a capacitor, a high-output alternator, or possibly a combination of both.

#3. Factor in Costs: While capacitors tend to be the more affordable option upfront, a high-output alternator may provide a more robust, long-term solution, particularly for high-performance audio systems. 

Remember to factor in additional accessories, wiring, and potential installation costs as well.

#4. Safety and Proper Installation: Whichever component you choose, ensure it is correctly installed. Incorrect installation can lead to performance issues and potentially damage your car’s entire electrical system.

I’d like to end on this note: in the capacitor vs high-output alternator debate, there’s no definitive answer that’s perfect for everyone.

It depends on your unique needs, the specifics of your car audio system, and your budget. Take your time to understand these components and make the decision that’s right for you.