How To Wire A Car Stereo To A 12 Volt Battery?

Buying a new car stereo is exciting as it takes your in-car entertainment experience to a new level. When you get a new head unit, you might wonder how you can test it to confirm that it is working well.

You need not install it on the car dashboard to check this. You can simply connect it to a 12 Volt battery that is generally used in electrical systems. 

You don’t need any technical knowledge to wire your car stereo to a 12 Volt battery. It can be done in a few simple steps with some basic tools. In this post, we outline this easy process to have your car stereo powered up in no time.

How To Wire A Car Stereo To A 12 Volt Battery?

What Parts Will I Need?

  • Stereo single or double din (Buy Here)
  • At least two speakers. (Buy Here)
  • A roll or speaker wire if planning to have speakers more than 4 inches from stereo (Buy Here)
  • A 12v Battery, can be lithium ion or lead acid
  • A bundle of red wire for the accessory wire from stereo (Buy Here)
  • A bundle of yellow wire for constant power to stereo (Buy Here)
  • A bundle of black wire for the ground wire from stereo (Buy Here)
  • Terminals for Power and Ground wires from stereo to battery (Buy Here)

Step By Step Guide to Wiring a Car Stereo to a 12 Volt Battery

While connecting a car stereo to a battery is a pretty straightforward task, it is recommended that you keep some simple tools handy to make it easier. You need screwdrivers, wire strippers, a panel removal tool, and tape.

Moreover, when you wire the stereo directly to a power source, you should consider using a fuse. This will protect your radio from any damage in case an electrical error occurs. 

Your fuse rating should be rated at an equal amperage value as the fuse found on the back of your stereo.

If you are using a factory-style OEM stereo you will need to check the back or bottom of the radio for its amperage rating.

Step 1. Ensure Sufficient Battery Charge

checking 12 volt battery

The first step in the process is to make sure that your 12 V battery is charged. If the battery doesn’t have enough charge, you should recharge it by connecting it to a mains charger. A battery without proper charge will not be able to power the stereo. 

Step 2. Identify the Wire Connections

Your car stereo comes with different wires present on the back of the wiring harness that connects to the audio system.

To be able to wire the stereo to the battery, you should first understand what those different wires stand for. It can, sometimes, be challenging to identify the wire connections. 

Look at the back of the harness to find different color-coded wires. Red and yellow are for memory and power while black is meant for ground. All the remaining wires are used for the connection of the stereo to external speakers. 

You should aim to find the positive of the battery, the accessory positive and the ground wire. A test light or a multimeter should make your job easier.

If you face any difficulty, you can refer to the instruction manual that comes with your radio. You should find the wiring diagram that explains these wires.

if you are using a factory stereo you will need to either cut the existing harness from the dash or order a new factory stereo harness that plugs into the back of your OEM stereo.

Step 3. Attach Terminals

crimping ring terminals

After identifying the wires, you need to use two metal terminals that you place above the battery posts.

This step ensures that the wires stay secure and stable and remain protected against knocks and vibrations. With these terminals, you don’t have to worry about vibrations dismantling your connections.

Step 4. Connect the Wires

Wire crimping

Start by connecting the yellow and red wires from the radio to the positive terminal of the 12-volt battery.

You should use a wire stripper to strip the red and yellow wires before attaching them to the battery. Next, take the black wire of the audio system and connect it to the negative terminal of the battery. 

When you attach these wires, you may see some sparks from the battery. This is completely natural and nothing to worry about. It signals that your battery has a good charge. 

Step 5. Secure the Connections

Once you have finished connecting the wires to the appropriate cables on the battery, the final step is to make sure the connections are secure.

You can connect the wires using multiple techniques. Some of the most common methods include twisting the wires together, soldering, using connectors, and wrapping in electrical tape. 

To make the connections durable, you should use a soldering iron to solder the wires together so that they stay for a longer time.

This type of connection ensures that your stereo gets power from the 12 Volt battery without any interruption. Connectors are also a great option because they keep the wires together for a long time by crimping. 

When you want to test the car stereo to confirm it’s working, you can simply use electrical tape to connect the wires. If you want to make the connections durable, consider using some permanent methods like soldering or connectors. 


Do I need a fuse to wire to the Battery?

No, Would I use a fuse? Yes. Using a fuse rated the same as your stereo’s fuse should suffice.

How long will the stereo stay on?

Usually about 3-6 hours.

What is the 12V accessory wire on a car stereo?

The 12v accessory wire is meant for turning on the stereo (allowing it to turn on) when the vehicle is started.


Wiring a car stereo to a 12 Volt battery is quite simple though most people find it daunting at first. With these steps, you can easily do it yourself to test whether your new car stereo works. We hope this guide helps you connect your audio system easily to a battery.