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“How many amps does a car radio use” is one interesting question that most vehicle owners, especially music enthusiasts, have always wanted a more precise or accurate answer to.

We all know the importance of a car radio, especially how incomplete and boring every ride may be in the absence of music or other fun content transmitted across this audio system.

However, little is known about how this entertainment system functions regarding the unit of electric current it uses or draws.

This article will discuss the number of amps a typical car radio or stereo uses and when you perform a few upgrades to your stereo system to achieve a more detailed sound quality.

What Is An Amp?

In a simple sentence, an amp, also known as ampere, is the unit used to measure electric current.

Current, on the other hand, indicates the number of electrons that are passing through a circuit.

How Many Amps Does A Car Radio Use?

This section answers the question- how many amps does a car stereo draw or use in a more detailed way.

This clarifies what you should expect while using the factory stereo and when you decide to upgrade your stereo system to meet your desired sound performance and expectations.

As you know, all stereos are not built the same way. Some designs are more powerful than others.

Also, the output level of the song you play or listen to on your stereo could influence the amount of power the car stereo uses.

Typically, a car stereo uses or draws between 5 and 10 amps. However, if your car stereo isn’t giving you the feeling and performance you deserve and you decide to raise things up a bit, the amps increase significantly.

When you make significant modifications or adjustments to the factory radio/stereo or install a top-quality subwoofer and amplifier, the amps could go as high as 30 to efficiently power them.

Usually, a powerfully built, reliable, top-performance amplifier that improves signal quality and provides cranky sound could draw between 10 to 30 amps.

To calculate amps, divide the wattage by volts. For instance, if you have an amplifier that uses 100W RMS with a 12V supply.

The amount of amps needed to power the amplifier is 100 divided by 12, which gives us about 8amps.

Also, an amplifier with 1000W with the same number of volts (12) will need about 83amps.

However, asides from the regular mathematical estimates or calculations, the amplifier’s efficiency also comes into play.

No matter how efficient an amplifier appears or is being patronized, it can never attain full efficiency.

Hence, you must factor in the system loss while calculating the number of amps that a car stereo uses or draws.

Lastly, you also need to know that the stereo still draws amps in most vehicles even when you turn them off or when they are not powered.

However, the amount of amps used during this period is low. Between 0.003 and 0.075 amps is nothing to be bothered about.

Step by Step Guide of Amps Installation in a Car

Pre-installation preps

Confirm if all the tools and accessories you need to successfully complete the installation are in order. Ensure the installation area is wide enough.

Also, decide if you need a helping hand and brief them about what exactly you want them to do.

Detach the battery

Now is the time to kick-start the process. Engage the parking brake, then disconnect the battery terminal (negative).

Pick a mounting point

Choose where you would like to house the amplifier. Some great location ideas include the trunk and under the seat. Once you have selected a location, you can then go ahead to mount the amp accordingly.

Power wire installation

Usually, the amplifier wiring kit comes with the power wire. The wire has a standard length between 16 and 20 feet.

The power wire is extended from the vehicle’s battery to where the amp is positioned or mounted.

During this exercise, you may search for a grommet (free or already occupied with other wires/cables) with adequate space to hold the power wire in place.

Add the fuse holder

Sometimes, the fuse holder may come already installed or attached to the power wire, right from inside the wiring kit. In case that’s not it, you will have to add it yourself.

Find an installation position or area. A spot that is not far away from the battery is a great idea. According to experts, about 6-inch away from the vehicle’s battery is perfect.

Once you find a suitable spot for the fuse holder, hold it firmly and securely in place using a screw.

Power wire connection

Now, connect the power cable to the battery. This time, directly to the positive terminal.

If your vehicle uses the top-mounted battery post, you may need some adjustments or modifications to your power wire before connecting it to the battery.

In most cases, the power cable has the ring terminal already attached to one end, just as many other cables in the amp wiring kit.

The ring terminal serves as the connector that is directly connected to the battery.

If your power cable doesn’t come with an already attached ring terminal. You can pick out this component in the kit and attached it to the power wire yourself.

Connect the ground wire

This connection is very vital to the success of the installation. Go to where the amplifier is positioned or installed.

Look for a free and clean bolt on the vehicle’s chassis where the ground wire can be connected.

The ground wire also has a ring terminal at one end, which connects directly to the bolt (the grounding source).

Install the turn-on wire

Afterward, install/connect the turn-on wire accordingly. If you use the aftermarket stereo, this wire has a blend of blue and white.

This wire sends a command to your amplifier to come alive whenever you switch on your stereo.

You will have to unseat or detach your stereo to get gain access to this wire. Once identified, you can connect it to the turn-on lead that comes with the amp wiring kit.

If the radio/stereo in your vehicle doesn’t come with the turn-on output, the fuse box can be used to gain a turn-on signal.

You can easily connect the turn-on lead to a fused output terminal of your choice, provided it is powered solely upon the activation of the engine. For instance, the one designed for your stereo.

Once the connection has been established successfully, the next step is to extend the turn-on lead to your amplifier.

One of the easiest ways to get this done is using the RCA cable.

Afterward, activate the signal connections.

Connect the speakers

This is the stage where you make the necessary wire connections to ensure the speakers are connected to the amplifier.

The easiest way to get this done is to disconnect the factory speaker cables.

Afterward, connect a new wire to each amp output and then extend these wires one after the other to each speaker.

Check if all wires are intact and make necessary connections

Check if all the cables used during the whole process are intact and then extend them to their respective ports on the amp.

Ensure they are well connected and securely held or attached in position.

Also, check if detached components or parts such as the negative battery terminal is replaced or reattached accordingly.

Try it out

Now that you have followed the installation steps and all the tips the manufacturer has advised and recommended, your amp should be ready for use.

Turn on the ignition and power on the radio/stereo. Check if the amplifier is active.

Play your favorite music and confirm if you are satisfied with the experience.

You can then adjust the controls and turn on the necessary features that support/enhance sound quality on the amp.

You may need to check the wiring at each connection point to confirm they are in the proper order if the amp fails to come up or doesn’t deliver on the expected expectation.

Best Car Radio Amp Reviews

01. BOSS Audio Systems R1100M


Highlighted Features

  • 1100 Watts maximum power
  • 13 x 10.44 x 2.25 inches in dimension
  • Single-channel
  • 8 pounds in weight
  • Switchable bass boost

A well-packaged product which you will fall in love with straight from inside the box. BOSS Audio Systems R1100M offers an impressive improvement in sound quality.

The functions can be easily controlled via the remote that comes with it.

This is a product that you can rely on if you are looking for an amplifier that doesn’t cost more yet offers outstanding improvement in sound experience.

It has gained thousands of positive reviews on Amazon, indicating how satisfied and fulfilled existing users are about its overall performance.


  • Comes with a remote for easy operation
  • Offers clean, loud, and smooth sound
  • Durable and affordable design


  • No wiring accessories

02. Planet Audio AC1500.1M Monoblock Car Amplifier


Highlighted Features

  • 1500W max power
  • Remote subwoofer control
  • 10 x 10 x 2.4 inches in dimension
  • Variable bass boost
  • MOSFET power supply
  • 69 pounds in weight

If you are looking for a product that supports a remarkable upgrade of the vehicle’s factory stereo setup without breaking the bank, here is an excellent choice for you.

The Planet Audio AC1500.1M Monoblock Car Amplifier is designed to offer outstanding improvement in sound quality.

Impressively, this amp eliminates noise and interference completely, ensuring you enjoy a clean sound at every use.


  • Comes with a user manual to support easy installation
  • A great product choice for individuals on a budget
  • Works excellently with your stereo/audio setup
  • Reliable, consistent, and long-lasting performance


  • Gets hot after long hours of use

03. BOSS Audio Systems R1004


Highlighted Features

  • 4 channel
  • 400 Watt max power
  • 8 x 9 x 2 inches in dimension
  • Power LED Indicator
  • Switchable input sensitivity
  • 1 pound in weight

BOSS Audio Systems R1004 is designed to provide both new and experienced amplifier users with an affordable design that offers improved sound and performance.

If you are looking for a compact and lightweight amp that won’t accommodate excessive space in your truck.

This product fits perfectly into your descriptions. The installation is easy, and it handles your audio system without any flaws.

This amplifier is dependable, and it provides impressive power and enhances your sound experience greatly.


  • Guarantees desirable balance between both sound quality and power
  • Goes off on its own when it becomes extremely hot after long hours of use
  • Provides remarkable power, volume, and sound clarity.


  • Produces some whining sound. You may need to invest in noise filters to solve this issue

Common problems of Radio Amps

  • Amp won’t come on: When this happens, check the wire connections to see if they are in excellent condition or well connected.
  • No sound: If your speakers fail to give out sound, check the speakers for fault or damage. Also, confirm if the wires that extend from the speakers to the amplifier are still properly connected. You may want to unplug these cables and reconnect them back.
  • Distortion: When you experience sound interference from the speakers, you may want to check if the wires, including the ground wiring, are in good condition. You can also reach out to a professional to fix this issue for you.

FAQ’s About How Many Amps Does a Car Radio Use

What gauge wire is applicable for a 1000W amplifier?

If you own an amplifier that uses 1000 watt RMS, a 4 gauge wire is applicable in that case.

Also, the power cable’s gauge and the ground cable’s gauge must be similar to guarantee a proper and consistent current flow.

How do I choose the ideal type of amplifier for my audio system?

If you are looking at powering only your speakers, a 2-channel amp will do the job perfectly.

To power the speakers and a subwoofer, a 3-channel amp is a great choice.

However, if you are looking at achieving a more powerful audio performance and as well create space for future expansion. A 4-channel amp is what you need.

What are the pros and cons of installing or housing the amplifier in the trunk?

If you are investing in a bigger amplifier, the trunk provides enough space to house or store it.

Asides from that, another advantage is the easy access to the amplifier controls.

Talking about the cons, you will need to buy more cables. Also, the installation reduces the space you have available to store your luggage or goods.

How long should the ground wire be?

Ideally, the shorter the length of the grounding wire, the better the performance.

While grounding your amplifier, ensure the distance between the grounding spot and the amp is at most 18-inch.

What wiring and accessories are required for amp installation?

When shopping for an amplifier to install in your vehicle, ensure you purchase the wires and accessories that you need for the project.

Usually, amplifiers do not have any wiring components packed inside the kit.

You have to buy the supporting accessories separately. You will need the RC cables, inline fuse, power, speaker, ground, and turn-on wires.


We hope you have gotten a more precise answer to “how many amps does a car radio use.”

Whenever you are thinking about getting the best out of your audio system, ensure all the components (the radio/stereo, speakers, and amplifier) are rightly connected and well managed.

This is the only way you can achieve a mind-blowing sound experience at every point in time.

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