How to Wire a Solar Panel to an LED Light (Steps, Extending Switch & Testing Tips)

Follow these simple steps to install a solar panel and use the power generated to light up your garden or driveway.

Powering an LED light from a solar panel is a good long-term energy-saving decision, as it can reduce your electricity bill. Using our guide, you can save on the installation cost and have your solar panel system set up without requiring an electrician.

I will first show you how to wire a solar panel to an LED light. You can easily extend the system to get further benefits when you are confident.

In a simple setup, all you need besides the solar panel and LED light are two wires and a resistor. We will wire the LED light directly to the solar panel. I will then show you how to extend this system by adding a switch, rechargeable batteries, an LED or charge controller, a capacitor, a transistor, and diodes. I will also show you how to test the current, in case you need to do that.

The Things You Will Need

To wire a solar panel to an LED light, you will need the following nine items:

• A solar panel
• LED light
• An LED controller
• Wires
• Connectors
• Wire Stripper
• Crimping tool
• Screwdriver
• Soldering iron

An LED typically requires only a little power, so if you use the solar panel only for the LED light, it doesn’t need to be a large or powerful panel. When you buy the solar panel, you should have a copy of the wiring diagram, but if you don’t, it’s a simple process, as explained below.

Wiring a Solar Panel to an LED Light

A Simple Method

The simple method for wiring a solar panel to LED lights requires little material and preparation.

It is suitable for when you want to get the job done quickly and without much effort. With the optional extras, which I will describe further on, you can extend the capabilities of this system later on.

Besides the solar panel and LED light, you only need an LED controller (optional), two wires, and a resistor.

Let’s get started.

If you inspect the back of the solar panel, you will find two terminals with their polarities marked on them. One should be marked positive or ‘+,’ and the other negative or ‘-.’ Even if only one is marked, you will know that the other is of the opposite polarity.

We will connect the two like polarities with wires and insert a resistor in the positive wire. Here is the wiring diagram:

A wiring diagram for a simple solar panel with LED light setup

To wire the solar panel to an LED light in a simple way:

1. Strip the wire ends (about half an inch).
2. Connect the wires using the crimping tool
3. Attach each contact to a connector for each wire, as indicated in the wiring diagram.
4. Using these connectors, connect the solar panel to the charge controller.
5. Bind with the charging regulator using a screwdriver.
6. Connect the LED controller to the LED.

You can now use the solar panel to power the LED light.

Wiring a separate LED light in the circuit as an indicator can give a visual indication of whether the solar panel is on or off (see picture below).

Other Components You Can Include

The simple setup above is going to be limited.

To better control the LED’s operation, you can wire the LED light to an LED controller and then the latter to the solar panel. But there are other components you can also connect to the solar panel-LED circuit you made.

In particular, you can add the following:

• A switch to control the circuit, i.e., switch it on or off.
• A rechargeable battery if you want to use the LED light connected to the solar panel at any other time during the day than when there is sunlight.
• A charge controller to prevent the batteries from overcharging (if you use a battery and have more than 5 watts of solar power for each 100 AH of battery capacity).
• A capacitor if you want to reduce the interruptions while the solar panel is operating, i.e., when something comes in the way, blocking the light source. It will smoothen the electrical supply from the panel.
• A PNP transistor can be used to detect the darkness level.
• A diode will ensure the current flows in only one direction, i.e., from the solar panel to the LED lamp and batteries, not the other way around.

If you choose to add rechargeable batteries, I would recommend you also include a diode in the circuit that allows current to flow only in one direction. In this case, it will allow it to flow from the solar panel to the battery but not vice versa.

If you use a capacitor, a basic LED light may require a capacitor rated at 5.5 volts, or you can use two at 2.75 volts each.

If you include a transistor, it will be controlled by the solar panel’s voltage so that when the sunlight is too high, the transistor should switch off, and when there is no sunlight, the current should flow to the LED.

Here is one possible wiring diagram that includes a battery, a transistor, and two diodes.

Testing the Current

You may need to test the current for brightness or another power issue with the LED light.

I will show you how this is done using a low-powered LED in electronic circuits. Specifically, I tested this method using a solar panel rated at 3 volts and 100 mA. Also, I used a multimeter, a gooseneck lamp, and a ruler. In addition, you will need a battery for this test.

Here are the steps:

Step 1: Prepare the Multimeter

Set the multimeter to measure DC, in this case, in the range of 200 mA.

Step 2: Connect the Test Lead

Connect the solar panel’s red wire to the long LED lead using one alligator clip test lead. Then connect the multimeter’s red probe to the LED’s short lead and its black probe to the solar panel’s black wire. This should form a series circuit, as shown below.

Step 3: Test an LED

Position the LED to be tested about one foot (12 inches) above the panel and turn it on. The LED should light up. If it doesn’t, then recheck the wiring and the multimeter’s setting.

Step 4: Check the Current

Obtain a current reading on the multimeter. This will show you exactly what current is passing through the LED. You can check the LED’s specifications to see whether this current is sufficient.

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