How to Wire Headlights Directly to Battery? – 3 Easy Methods

You are not getting enough power to the headlights? Are you tired of your vehicle’s headlight issues? To get more power from the headlights, you should wire them to the battery.

So, In this article, we’ll explore how to wire headlights directly to battery.

You can wire headlights directly to the battery with a relay, or by wiring a parallel connection. Wiring the headlights directly to the battery drains the battery faster. Also, it can overheat the battery and cause a fire. The solutions are to use a relay or connect the batteries in parallel.

We’ll discuss all the possible methods of wiring headlights directly to the battery. Alright, let’s jump into the discussion real quick. 

Can You Wire Car Headlights Directly To Battery?

You can definitely wire car headlights directly to the battery. There are primarily three methods to this. The first one is the method itself, wiring the battery directly to the headlight. Secondly, using a battery relay, and the last one is wiring in parallel.

FactorsMethod 1Method 2Method 3
Wiring MethodsDirect wiringUsing a relayWiring in parallel
Pros and ConsCheck Pros and ConsCheck Pros and ConsCheck Pros and Cons

All of these methods have different steps, advantages, and disadvantages. Also, these methods are more or less similar for both cars and bikes. We will explore all these three methods step by step in detail. Let’s start with the first method.

How To Wire Headlights Directly To The Battery? [For Car]

To wire the car headlights directly to the battery you will be needing some tools first. Look at the checklist below.

Tools required:

Precaution and Safety Tips.

  • Wear protective rubber gloves to prevent getting shocked by the car battery.
  • Wear safety goggles to protect the eyes.
  • Avoid direct skin contact with the battery fluids.
  • Check for visible battery cracks or damages.
  • Be extra careful with the positive and negative wires.
  • Avoid all kinds of ignition sources, such as flames and cigarettes.  

Step 1: Set the Battery in a Suitable Position

Before you start with the process, put the battery in a suitable position so you can easily access the wires. It’s because you will need to connect and disconnect the wires. Also, make sure the battery is placed in a well-ventilated area to prevent overheating issues.

Step 2: Disconnect the Battery.

First of all, make sure the battery is disconnected completely before beginning the wiring process. It’s because if the battery is running while wiring it can fire up. In the worst cases, it can catch fire and cause injury.

Step 3: Prepare the Battery for Wiring.

The next step is preparing the battery after disconnecting the cables. You have to make sure the battery terminals are clean and rust-free. If the terminals have any corrosion or rust, clean them using sandpaper or brush.

Step 4: Disassemble the Headlight Parts

Now remove the headlight assemblies using the Philip head screwdriver. Disconnect all the headlight-related wires connected to the headlight.

Depending on the car model, the disassembly procedure may vary. So, make sure to check the instruction manual provided by the manufacturer of your car.

Step 5: Split and Splice The Wires

You’ll see two pieces of the wires. Now use a wire cutter to split the top part of the wires. By doing this you will get two wires, the electrical wire and the wire that connects the headlight. Now splice the wires together carefully with a wire splicer for convenience.

Step 6: Connect the Wires

Now connect the wires according to the battery terminals. Connect the negative(-) or black cable to the battery’s negative terminal. Then, connect the positive(+) or red cable to the battery’s positive terminal. 

Now turn on the headlight to check if they are working properly or not. If the headlights are working, congratulations on that, you’re done.

Pros and Cons of Connecting Headlight Directly to Battery

More power to the headlight.Brighter and stable lights.Permanent installationMay overheat the lights.Voltage surge may damage the lights.High battery consumption.Drains the battery faster.

As we can see, wiring the headlights directly to the battery has some pros as well as cons. One of the most concerning disadvantages is, this process drains the battery faster. The headlights will run constantly even when your car is turned off completely.

How to Wire Headlights Directly to Battery Using a Relay?

Another method of wiring headlights directly to the battery is by using a relay. Now you might ask, what does a relay do? Also, do you really need one? 

A relay is an electronic device that separates power circuits from control circuits. It’s responsible for controlling the high voltage device such as your car’s headlight. This makes sure that the headlight gets proper and adequate power.

Relay also prevents high power surges to prevent overheating and sudden damage. It also automatizes the power supply directly from the battery. They’re cost-effective and easy to set up.

How to Wire Headlights Directly to Battery Using a Relay

Image Source: 12 Volt Planet

Before we get into the wiring, we must have an idea of the relay’s terminator pins and what they mean. Below a table is added for a quick overview of the relay terminator pins. 

Terminator Pin/NumberConnection
87NO (Normally Open)
87aNC (Normally Closed)
30For both NO and NC terminals

Now that we have an idea of the terminator pins, let’s get to the wiring. To wire headlights with a relay follow all the steps from 1 to 5 as we have done before. Now follow the below instructions thoroughly.

  • First, prepare the relay by setting it to your desired position. It is recommended to set the relay away from moving parts.
  • Now take the negative or black wire and connect it to the negative terminal of the relay. If you can’t find the negative terminal on the relay, look for “86” written on the terminal. 
  • As we have mentioned in the earlier table, terminal 86 is a coil that completes the circuit. It flows the current from the battery to the headlights. Now use electrical tape to cover the relay terminal. 

Congratulations! You have successfully wired the headlights using a relay. 

Pros and Cons of Using a Relay

Provide the shortest route from the battery to headlights.Prevents voltage drop and surge.Ensure the proper use of the fuse.Can tolerate power loads up to 30 amps.Requires proper setup.May require a good AWG gauge  wire for peak performance.

So, we can see there are many advantages compared to disadvantages. Hence, using a relay while wiring headlights directly to the battery would be a great choice. 

How to Wire Headlights Directly to the Battery in Parallel?

How to Wire Headlights Directly to the Battery in Parallel

Image Source: Technology Student

Most modern vehicles nowadays come with parallel wiring by default. However, the old model cars have the wiring in series. There are proven advantages of parallel wiring over series wiring. That’s why modern cars have shifted their wiring styles.

Now let’s check out how you can wire your car headlights in parallel. Follow the instructions below step-by-step. 

  • First, identify the headlight terminals. The positive terminal is red and the negative is black carved with a minus(-) sign on it.
  • Now, take one wire and connect it to the positive terminal on one headlight. Then connect it to the positive terminal of the other headlight.
  • Follow the same process to wire the negative terminal. Then, connect the negative terminal of both headlights with another length of wire.

In this way, all the positives and negatives become connected. But if one headlight fails it won’t affect the other one because the circuit maintains the same voltage. That’s the core benefit of parallel wiring. 

Now, let’s check out the pros and cons of using parallel wiring.

Pros and Cons of Parallel Wiring

Maintain the same voltage supply.Parallel wiring helps to extend the battery runtime.No interruption if one of the devices fails within the circuit.Parallel connection needs more wires compared to series.Adjusting for specific current flow or voltage is complicated.Increasing the voltage results in increased resistance in the circuit.

We can see that there are valid reasons why the automotive industry prioritizes parallel wiring. So, wiring the headlights in parallel is definitely a good solution.

Our Recommendation: Which is the Better Way?

Our personal recommendation would be the relay one. The relay method is the best and safest way to wire headlights directly to the battery. 

Well no one wants to damage their precious headlights, right? The relay method provides you with the safety of not damaging the lights if something goes wrong.

We’ve also demonstrated how important the role of the relay plays while wiring lights directly with batteries. It can control the current flow to the headlights from the battery. In this way, it prevents sudden voltage surges or voltage drops in the connection. 

Extra: How to Connect Bike Headlights Directly to The Battery?

Wiring the bike headlights directly to the battery is pretty easy comparatively. Now follow the below steps.

  • First disassemble the headlight panel using a screwdriver. Note that the disassembly procedure may vary depending on the bike’s brand and model. So, assure that you check the user manual.
  • Now, after removing the panel, find the wire in full yellow. There can be other yellow-green wire too but we need to find the full yellow one.
  • Then another bunch of black wire. You’ll see 2-3 three wires connected together and all of them should be black. There should be one empty slot.
  • Now, disconnect the yellow wire from the connector. And, plug the wire into the empty slot of the black wires. Use wire tape to insulate the other part of the yellow wire.

Well done! Your headlight is directly connected to the battery now. If you want to go back to the previous mode, just attach the yellow wire to the previous connector.


How Many Led Lights Can A Single Car Battery Connect?

If your car has a 12-volt battery, you can connect 12V/3.5V = 3.4, which means 3 LEDs maximum. Normally, LED lights consume 3.5V per light. You can add 3 lights either in the series or parallel connection. But wiring the LEDs in parallel is recommended.

Why Do Headlights Have Three Wires?

If the headlights have three wires it means the LED is multifunctional. You’ll see the red, black, and white wire. The red one is the positive cable and the black cable works as the second positive. And the white cable is for grounding. You can use multifunctional both as a blinker and brake lights.

Do Headlights Need A Relay?

You’ll only need a relay for high-powered headlights. Headlights have a fuse attached to them to prevent unexpected damage. Similarly, the relay protects the fuse from getting damaged by high current flow. It also ensures proper current flow and prevents voltage drops within the circuit. 


So that’s all we had to discuss regarding your query on how to wire headlights directly to battery. Hopefully, the article was helpful. We tried our best to provide the easiest solutions to solve your issue.

Let us know if we have missed anything. We will try to cover it up in the next one.

Goodbye for now!

Leave a Comment

Your email address will not be published. Required fields are marked *