Photo of Solar Lights

How do Solar Lights Work?

Solar lights are a trendy addition to a lawn or garden. They come in all kinds of shapes, from string lights or stake lights to hanging lanterns and even security lights.

They are low maintenance, usually turning on by themselves at night when they are needed most.

Better yet, they don’t require an outlet, an external battery, or a power supply, so they are free to operate. But how do they work? Let’s find out.

Parts of a Solar Light

Whatever specific type of solar light you have, it always consists of these essential parts:

A Light Bulb

Most modern solar lights use LED light bulbs because LEDs emit a lot of light with less energy and can reliably last for a long time.

Solar Cells

Solar cells, or photovoltaic cells, generate electricity from sunlight. Solar lights for the garden use the same technology, but in a smaller size, as the technology used in rooftop solar panels.

A solar cell comprises layers of crystalline silicon that create layers of positively and negatively charged space inside the cell.

When the cells are exposed to sunlight, the electrons become excited and jump free, moving charged particles across the positively or negatively charged barriers.

The motion of electrons generates electricity.

A Battery

Like those on calculators, some solar cells only generate as much electricity as needed at the moment.

But solar lights are made to generate electricity and store it for use later, after dark.

So the electricity produced by the solar cells in the daytime is stored in the battery, where it is later used to provide power for the light bulb.

A Photoreceptor

Solar lights also usually have a light sensor or photoreceptor. This lets the device know when it has become dark outside and triggers the light to come on.

Some solar lights also have timers or other ways to turn the light on and off.

A Charge Controller

A charge controller regulates the current inside the light. It prevents the battery from overcharging during the day or over-discharging at night, protecting the device’s safety and longevity.

They may also prevent overheating or other damage.

In most solar lights, all these parts are integrated into a small collection of components and circuits, each of which helps the light work properly.

How do Solar Lights Work?

Photo of Solar Light in night

When a solar light is working correctly, all these components do their part. A solar light works like this:

  • During the day, sunlight strikes the solar cells. The electrons start moving, which generates electricity
  • Electricity is transmitted to the battery, which recharges
  • The controller regulates the flow of current, preventing the battery from over-charging or over-heating
  • When the sun goes down, the receptor responds to the changed lighting conditions
  • The light bulb is activated, drawing power from the battery
  • Over the night, the battery powers the light bulb and is slowly drained of energy
  • The controller prevents the battery from discharging too much energy at night
  • The next day the cycle starts all over again.

How Long Do Solar Lights Last?

Because solar lights are low maintenance, and the batteries recharge themselves, you may be wondering how long a solar light will last.

For the most part, the light will last for as long as the components will last. For example:

LED Light

An LED light will last for 10-15 years

Solar Cells

A solar cell may last for decades, but it may be damaged if the crystalline structure gets broken or become less efficient at generating electricity if the surface gets dirty or scratched over time.

The Battery

While battery technology has improved exponentially in recent decades, most ordinary rechargeable batteries in a solar light will only last for 3-4 years.

Keeping a solar light clean and in good condition will help it last longer and produce light more efficiently.


Solar lights are a simple, affordable, and long-lasting way to add light just where you need it, indoors or outdoors, without requiring additional electricity or nearby outlets.

These technologies continue to improve, giving you more options in better solar lights that generate more light and last longer.

Now that you know how solar lights work, you have a better idea of choosing solar lights or maintaining any solar lights you already have.

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