What Size Alternator Is Best for Your Car Audio




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Standard alternators might not be sufficient for high-demand systems, which often necessitates the consideration of a high-output alternator. But what’s the right alternator to use for your audio system in the car? Let’s find out.

The alternator should produce at least 25% more power than the audio system, including the car audio system requires. This ensures that your battery stays charged and your audio system runs smoothly.

Key Takeaways
Understanding your car audio system’s amp requirements is vital for determining your desired alternator size.
The size and power of your car audio system, the type of music you play, and the quality of your vehicle’s electrical system can all influence the alternator size you require.
Using a larger-than-recommended alternator can offer benefits like increased power supply and reduced strain on the electrical system, but also potential downsides like compatibility issues and higher costs.
When upgrading your car audio system, consider the build quality, power output, and reliability of various alternator brands.
There’s no one-size-fits-all solution for alternator size. The right choice depends on your specific audio setup and personal preferences. Balance is key in a car audio system, with every component working in harmony.

Without a properly functioning alternator, the audio system will not work correctly, and the battery will not be able to recharge. For more information, read the article about the function of an alternator in a car audio system.

How to Determine What Size Alternator Your Car Audio System Needs

Determining the correct size alternator for your car audio system can seem daunting, but it’s simpler than you might think! Here’s how you can make it right.

which is the best alternator size for car audio

Understanding Amp Requirements

Before we go any further, let’s talk about amps. In car audio, the term ‘amps’ is commonly used to describe the amount of power an amplifier requires to operate.

Your amp requirement is a crucial factor in determining the size of the alternator your car audio system needs. If your amp needs more power than your alternator can provide, the system will draw power from the battery, draining it quickly and potentially causing damage.

On the other hand, if your alternator is too powerful, you may waste the unused produced power.

What Size Alternator Do I Need for 2 Batteries?

Having additional batteries in your car can significantly change your alternator needs. In this case, you’re going to need an alternator that can keep up with the increased demand for power, but it is not about the number of batteries but about their capacity.

When considering the right alternator size for two batteries, you need to factor in the following:

  • The ampere requirements of your car audio system.
  • The combined capacity of your two batteries.
  • The existing electrical demands of your vehicle.

Factors to Consider When Choosing the Size of Car Audio Alternator

Determining what size alternator is best for your car audio is not just a numbers game. It’s also about understanding various factors that could influence your choice. Let’s take a closer look.

Car Audio System Size

As previously mentioned, the size and power of your car audio system directly affect the size of the alternator you’ll need. It’s not just about loudness, but also about the complexity of your setup.

Do you have multiple amps, high-powered speakers, or a subwoofer? Each component in your audio system has its own power requirements, which adds to the total load that your alternator needs to handle.

For example, if you have a basic car audio system – a head unit, a couple of speakers, and perhaps a small subwoofer – a standard alternator may suffice.

However, if you’re an audio enthusiast with multiple high-powered amps and a collection of large subwoofers, a high-output alternator may be required to meet the amperage demands of your system.

Electrical System Quality

Finally, let’s talk about your vehicle’s electrical system. The quality and capacity of your electrical system play a critical role in determining the size of the alternator your car can handle.

Factors to consider include your vehicle’s belt setup, fuse rating, and gauge amp kit. If these components are not built to handle a high-output alternator, installing one could potentially cause damage.

Here’s how you can assess the quality of your electrical system:

  • Belt Setup: Check if your vehicle’s belt system can handle the increased load of a high-output alternator.
  • Fuse Rating: Ensure your vehicle’s fuses can handle the increased amperage a high-output alternator may produce.
  • Gauge Amp Kit: Verify if the wiring in your vehicle can accommodate the power output of a high-output alternator.

Considerations for Using a Larger Than Recommended Alternator

When it comes to your car’s alternator size, is bigger always better? Let’s explore the potential benefits and drawbacks of using a larger than recommended alternator for your car audio system.

Benefits of a Larger Alternator

It might seem counterintuitive, but there can be benefits to using an alternator that’s larger than what’s typically recommended for your car audio system. Let’s dive into a few of them.

#1. Better Power Handling: A larger alternator can handle high amp loads with more ease than a smaller one. This means it can keep up with power-hungry components in your audio system, like high-output amplifiers and subwoofers.

#2. Reduced Battery Strain: If your alternator can supply the needed power, your battery doesn’t have to work as hard. This can potentially extend your battery’s life.

#3. Prepared for Upgrades: If you plan to upgrade your car audio system in the future, having a larger alternator ensures that your vehicle is ready to handle the increased power demands.

Risks and Downsides

While there are benefits, using a larger than recommended alternator isn’t without its risks. It’s crucial to understand these potential downsides before making a decision.

#1. Potential Overload: If your vehicle’s electrical system (including the belt setup, fuse rating, and gauge amp kit) isn’t equipped to handle a high-output alternator, it could potentially overload and cause damage.

#2. Increased Fuel Consumption: Larger alternators require more energy to operate, which can lead to slightly higher fuel consumption.

#3. Cost: High-output alternators are typically more expensive than their standard counterparts. You’ll need to consider if the benefits outweigh the initial cost.

The Best Brands of Alternators for Car Audio Systems

In the world of car audio, there are a handful of alternator brands that have established a name for themselves due to their high-output alternators marketed specifically towards audio enthusiasts.

Of all the known alternator manufacturers, my favorite is Mechman. If you’ve got a car audio system that needs a lot of power, Mechman has you covered.

Key Features to Look For in an Alternator Brand

Not all alternators are created equal. Some brands may offer a high-output alternator, but it may fall short in terms of build quality or reliability. 

Here are some key features to consider when choosing an alternator brand:

  • Build Quality: The build quality of an alternator is paramount. It’s what ensures your alternator can handle high amp loads consistently without failing. Brands that use high-quality materials and rigorous testing processes often provide better, more reliable alternators.
  • Power Output: Check the amperage rating of the alternator. Remember, you’re looking for an alternator that can handle your vehicle’s basic electrical needs and your audio system’s power requirements.
  • Reliability: An alternator is an investment. You want a brand that has a proven track record of reliability and customer satisfaction. Read reviews and see what other car audio enthusiasts have to say about the brand.
  • Fitment: Make sure the alternator is compatible with your vehicle. The best high-output alternator in the world won’t do you any good if it doesn’t fit your car’s belt setup or exceeds your fuse rating.

Recommendations for Different Car Audio Needs

The best alternator brand for you will depend on your specific car audio setup and needs.

  • For a basic car audio system, brands like Powermaster or XS Power offer robust and reliable alternators that can handle moderate amp loads comfortably.
  • If you’re running a competition-level system, you might want to consider high-output alternators from brands like Mechman or Ohio Generator.

Further Reading About Car Audio Alternators

Choosing the Best Alternator for Car Audio

When it comes to choosing the best alternator for your car’s audio needs, there are a variety of factors to consider. You’ll want to think about the size and power requirements of your sound system, as well as the make and model of your car.

For more details, check out our article on choosing the best alternator for car audio.

Upgrading to a High Output Car Audio Alternator

If you are experiencing problems with your car’s electrical system due to your high-powered sound system, upgrading to a high-output alternator may be the solution.

A high-output alternator is designed to produce more power than a standard alternator, which can help to meet the demands of a high-powered sound system.


Understanding your audio system’s amp requirements is a crucial step in determining the right alternator size. For instance, if you’re running a high-output audio system or using multiple batteries, your amp requirements will be higher, thus demanding a more robust alternator.

The car audio alternator calculator can be a handy tool to help you determine the ideal size alternator based on your audio system’s power needs and your vehicle’s electrical demands.

Remember that the size of your car audio system, the type of music you play, and the quality of your vehicle’s electrical system can all affect the size of the alternator you need.