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How To Wire A Car Stereo To A 12V Battery: A Quick Guide

Last Updated on: May 11, 2024

You would undoubtedly agree that a stereo is an excellent addition to any car and may revitalize your driving experience, giving you hours of enjoyment on your lengthy drives. 


Wiring the audio system to a 12v battery is your best option if you want to test your new car radio to see if it functions or if you want to listen to your car stereo without worrying about draining the battery.

Contrary to popular belief, connecting a stereo directly to a 12 volt battery is simple. To complete the task, you simply need to follow basic instructions. In this article, I’ll outline the procedures. Let’s go!

7 Quick Steps On How To Wire A Car Stereo To A 12V Battery 

A car stereo can function and last a long time when it is connected directly to a 12-volt battery. You may therefore be confident that the stereo will operate to its full potential when placed properly. To connect the car stereo directly to a 12 volt battery, follow the steps outlined below:

1. Ensure The Car Battery Is Charged

Car Battery Is Charged

First, you must ensure the car battery is sufficiently charged. If the battery is low on power, I’d advise you to use a mains battery charger to recharge the battery. Car batteries without sufficient voltage can’t power any radio, so it’s important to charge it up.

2. Strip The Wires

Strip The Wires

Next, you need to strip the wires. Carefully remove the insulation from the ends of the wires using a wire stripper. This can be difficult to do but ensure you do not damage the wires while doing the task. 

Also, ensure the wires are properly stripped and strip only half an inch of insulation from the colored wires on the car stereo’s wiring harness so it can make a good connection. The red and yellow wires are the switched and constant power cables.

3. Connect The Yellow And Red Wires To Each Other

Connect The Yellow And Red Wires To Each Other

The yellow and red wires need to be connected to the positive terminal on your car battery, so you must pair the colored wires by twisting them together. Slide the twisted wires into the alligator clip. Use a crimp tool to crimp the cables into the clip. Then you can now connect them directly to the car battery. 

To ensure a good connection, the metal part of each pair of wires must touch each other. 

If they don’t make contact, the connection will not work. You can test the car stereo to guarantee it works properly.

4. You Must Also Crimp The Black Wire 

Crimp the black wire

The black wire is referred to as the ground wire. It is the main wire responsible for your car stereo’s functionality; the wire must be adequately grounded. You can connect the wire easily to an alligator clip. 

You will also need to use a wire crimper tool to connect the black wire to the negative terminal on your car battery. You can use a screw to connect the ground wire to the car to get a better-grounded connection. Also, when using the crimper tool, ensure it is the accurate size of the crimp connector. 

The size of the ground wire must be the same as the crimp connector. 

When the crimp connector is smaller than the wire, it won’t grip the wire properly, and if the connector is too large, the wire will be crushed. The suitable crimp connector for the wire gives a good connection.

5. Connect To A Battery

Connect To A Battery

You can now connect to a 12-volt battery since all the wires have been stripped and prepared for connection. When using a 12-volt battery, the red and yellow wires need to be connected to the positive terminal. In comparison, the ground wire must be connected to the negative terminal (opposite the colored wires). Locating the positive and negative terminals can be easy. 

If you have no clue, then you can look out for these signs — “+” means positive, while “-” indicates negative.

As soon as you have connected all the wires, you can then switch on your car stereo and enjoy your car audio set.

6. Connect Your Car Stereo To A Speaker

Connect Your Car Stereo To A Speaker

Firstly, you must locate a better place to mount your car stereo. Make sure it is mounted securely, so it doesn’t damage during driving. Then run a power wire from your car battery to where you mounted the car stereo. 

I’d advise you to use a thick wire that can handle the amps of your car stereo. 

The process won’t be complete until you connect the wires from the speakers to the car stereo. The speaker’s positive wire should be attached to the stereo’s positive terminal, and the speaker’s negative wire should be connected to the stereo’s negative terminal.

7. Turn On The Car Audio System

Turn On The Car Audio System

You can now turn on your car radio and listen to music through the speakers after all the tasks associated with connecting your audio system to the vehicle batteries have been completed. But if it’s otherwise, you should double-check the connections to make sure they are securely fastened.

Pro Auto Thought: Congratulations on your first DIY project! You successfully wired your car stereo to your car battery. However, upon switching it on, it doesn’t do anything because you need a code. Don’t fret! Read our post instead and learn how to bypass this minor inconvenience — How To Reset Car Radio Without Code.

Watch This!

Frequently Asked Questions

How To Connect A 12V Power Supply To My Car Stereo?

To wire a car stereo to a 12V power supply, the positive lead from the power supply will need to be connected to the positive electrode on the car stereo, and then connect the negative lead from the 12v power source to the negative electrode on the car stereo. In case your power source doesn’t have a fuse built into it, you can install one.

How Many Amps Does A Car Stereo Draw?

This solely depends on your car stereo, but regular car stereos draw around 10 amps.

Can A Battery Charger Be Used As A 12V Power Supply?

Yes, of course, you can use a battery charger as a 12-volt power source. It’s crucial to point out, though, that the battery charger will not offer enough power like the 12-volt power source. The battery charger is just not strong enough to carry a huge load of electronics. 


Unlike most people’s assumptions, directly connecting your car stereo to a 12-volt battery is not difficult. It is an easy procedure that may be carried out without any problems or technical know-how. 

However, if you have doubts about your capacity to complete this procedure, I suggest you get professional assistance to help you connect the car stereo directly to the vehicle’s battery. The wiring kit will also be installed appropriately, ensuring the car radio operates flawlessly.

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