How Do Solar Lights Work?


Outdoor lights use a solar cell to collect sunlight. The energy is stored in batteries then converts sunlight to electricity to illuminate the light at night. Solar lights have a sensor that keeps the light off during daylight hours to conserve energy.

Since their invention by Bell Labs in 1954, modern solar cells have been useful in various applications. Solar cells currently power our satellites, the Mars Rover, toys, homes, and outdoor lighting systems. But how do solar lights work? That discussion should begin with learning what they are.

What Are Solar Lights?

Solar lights are stand-alone, individual lights that provide inexpensive outdoor lighting options. Available in various styles, solar pathway lights are one of the easiest Do-It-Yourself (DIY) enhancements for a homeowner to make. Solar-powered lights are sold as single units or in matched sets. Most good pathway lights have a mounting stake.

Lights can also be connected in a series, similar to traditional lighting solutions, with solar panels set up in direct sunlight as a collector. This type of system has a higher capacity for energy storage which will keep the lights on for a more extended period. Solar lights have many uses, including pathway lighting, wall-mounted area lighting, freestanding lamp posts, security lighting for drives, walking paths, and more.

Because the sun’s energy powers them, they don’t add a penny to your utility bill. Sensors on many lights will illuminate as darkness falls, while others will light when they sense nearby motion.

How Does Solar Power Work?

To understand how solar lights work, let’s start with the four main components: The solar photovoltaic (PV) panel, the battery, electronics, and the fixture (with mount).

Standard outdoor solar lights have a series of PV cells, typically four cells, that produce 1.8 volts (up to 100 milliamps) in full sunlight. The solar panel, measuring about 2 inches by 2 inches, connects to a small battery within the fixture. A diode in the circuit prevents the current stored in the battery from flowing back through the solar cell. Most outdoor lights use a standard AA-size Nicad rechargeable battery. The battery charges throughout the day, although it may not fully charge on cloudy or overcast days.

A sensor turns on the light-emitting diode (LED) when the sun goes down. The length of time that your outdoor lights remain illuminated depends on the amount of charge, the age of your light fixture, and other factors. Most solar lights will remain lit for six to ten hours, although they may be quite dim at the end of that cycle.

Solar Energy Collectors – Optimizing the Sun’s Energy

Placement is essential to optimize the ability of your outdoor lights to collect and store solar power. Most yard lights are self-contained, meaning the solar panel and the light are one item. When you place lights, you want them near a walkway or to provide illumination to a particular area, such as a garden.

Although a solar light system will work almost anywhere within the United States, it needs adequate sunlight. Each light must be fully exposed in an area to receive the recommended number of sunlight hours to charge completely.

How Do Solar Lights Store Energy from Sunlight?

Each independent solar light contains a separate PV cell. Energy is stored in a rechargeable battery within the housing. Each solar cell has layers of crystalline silicon that form positively-charged spaces and negatively-charged electrons.

The negatively charged electrons become excited and push into positive-charged spaces as sunlight travels through the cell. The electron stream then transfers through wires as direct current, stored in the battery.

The process repeats daily, as long as the sun is shining. At night, the stored energy from the battery powers the LED light until it is exhausted or the sun rises again.

Outdoor Solar Lighting Solutions

Solar lighting will never be as bright as an incandescent bulb. The low-voltage LEDs will only supply enough light to illuminate a small area. This usually is adequate to keep pathways safe or to highlight your garden. If you desire brighter lighting options, you should seek an installer for a low-voltage electric lighting system.

When you shop for outdoor lights, be sure to research. Finding a good outdoor solar lights buying guide can be instrumental in cutting through all the finer points.

Determine the type of lighting you want. Some choices include step lights, floodlights, landscape lighting, and even Christmas lights.

How Do You Charge New Solar Lights?

When you get your solar lights, you will need to allow them a full day of bright sunlight to charge them for the first time. We recommend finding the brightest spot in your yard and placing all your lights in a group with the solar receptors facing the direction the sun is coming from.

charging solar lights for the first time

Installing Your Solar Lights for Maximum Efficiency

Lights installed where they receive full sunlight for most of the day will stay illuminated longer through the night. When planning your installation locations, remember to allow for seasonal differences in the sun’s angle. Solar lights can lose 30 to 50 percent of their efficiency during the winter months.

You will also need to be aware of trees, shrubs, and buildings that may block sunlight. Position lights so that they receive optimum exposure to the sun’s rays. Although solar lights will charge in partial shade, they may not receive a complete charge, which can shorten the life of the fixture.

How Long Do Outdoor Solar Lights Last?

This question has several parts. You can expect the fixtures to last 3 to 5 years. You should perform general maintenance, such as checking and cleaning the solar cell yearly.

Batteries will typically last for 12 to 18 months, but some may last as long as 36 months. Batteries that receive a complete charge daily will last longer than those receiving only a partial charge. Your lights should have a data sheet with instructions on battery care.

Average outdoor lights will remain lit for six to ten hours. The variables that determine how long your lights stay illuminated include how well the light charged during the day, the age of the fixture, and the age and condition of the battery.

The bottom line on getting the most out of your solar lighting is taking care of your lights, keeping them clean, checking the batteries, and placing them in an area that receives full sun.

Light up Your Walks and Yard with Outdoor Solar Lighting

Now you understand the basics of how solar lighting can light up your life. Don’t forget the many benefits of having solar-powered yard lights. They are friendly to our environment by reducing your carbon footprint. You will also save money on electrical energy while lowering your risk of fire or burns from traditional lights.

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