Many different systems work together to make outdoor solar lights function. The solar panel has to collect sunlight and turn it into electricity that a battery can store. The light also has to turn on and off at the correct times. 

Then the whole thing has to be protected from the elements so it can do its job. Let’s take a look at each part and see how they all work together.

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So How do Solar Lights Work?

All different types of solar lights use these same components, from solar landscape lights to solar spotlights. The size and power of the parts change, but the overall configuration stays the same. 

There can be a lot of variation in style, but the general functions remain constant.  

How do Solar Lights Work?

Casing and Cover

The casing can be utilitarian, or it can be highly decorative and fun. Either way, the job of the case is to house other components and keep the electronics safe. It will enclose all your circuits, panels, and sensitive material.  

Pro Tip: If your light gets buried or falls in the mud, you might want to check in the case to make sure grim didn’t get in there. 

For outdoor solar lights like solar garden lights and solar Christmas lights, the cover also must be water and dirt-resistant. There are some pool solar lights that are fully waterproof. 

Solar Cells

The solar cell or photovoltaic cell takes sunlight and turns it into usable energy. Solar cells need a direct light source to work, so you want to make sure they get plenty of sunlight. There are many different styles of solar cells that can work with many kinds of solar panels.  

A basic solar panel uses the following steps to turn solar power into usable electricity. 

  1. The solar panel collects sunlight to the solar cell. 
  2. The cell uses photons from the sunlight to remove electrons from atoms.
  3. It funnels electrons into one direction to a battery that stores them for later use.  


A photoresistor or light sensor allows solar lighting to turn on and off based on the brightness in the area. When there is a lot of sunlight, the photoresistor turns the light off and allows the batteries to charge. When it’s dark out, the photoresistor provides electricity to light the bulb.

Did You Know: You can test your photoresistor by putting your finger over the sensor. If the light doesn’t come on, the photoresistor may be bad. 

Photoresistors can get fooled by artificial light. So if there is too much light on them, they can turn off even when it is dark outside. It would be best to space solar pathway lights far enough apart that they don’t accidentally turn themselves off when they come on. 


The battery in an outdoor light takes solar energy from the sunlight and stores it until nighttime. A solar light can have a bunch of different battery systems. 

Some of the most common include NiMH and NiCd batteries. Both of these options can work because they are small batteries that produce a decent amount of power. 

Pro Tip: If you take in NiCd Batteries in the winter, store them someplace with temperature control. A spot in your garage may still be too cold for them. 

Solar lights use NiMH when they have to stay on for a long time and deal with a broad range of elements. They work better in extreme weather conditions. This type of battery works excellent in solar Christmas and solar street lights. 

The older NiCd is still a good option for lighting because it is more affordable. Weather affects them more, and they don’t last as long. They tend to be used in summer lights that come in at the end of the season, like a solar garden and solar fairy lights. 

Controller Board (Lighting vs. Charging)

The controller board tells a solar yard light if it needs to light a path or charge its batteries. Photoresistors allow the controller to know if it’s day or night. 

When it is dark out, the board puts the power to the light source. When sunlight is available, the controller directs electricity to the battery. A charge controller makes sure that your battery doesn’t get overcharged. 

LED Light

Most indoor solar lights and outdoor solar lights use an LED light source. An LED light bulb can be tiny and energy-efficient. Compared to a traditional incandescent bulb, an LED bulb uses 90% less electricity

Solar LED lights save energy by producing less heat. They don’t become hot to the touch, so you don’t have to worry about people or pets brushing by them. LEDs are also safer for solar garden light and solar landscape lighting that may contact dry plants.  

Frequently Asked Questions 

If you have any other questions about solar lights, these answers can help. 

Do Outdoor Solar Lights Charge at Night?

Outdoor solar lighting doesn’t charge at night. The outdoor solar lighting system controller switches over to using the batteries when the unit doesn’t detect sunlight from the solar panel. The light will use energy stored until it runs out. Then it will recharge when in sunlight.

Some artificial light sources will cause outdoor lights to switch over and start storing power again, but when this happens, the bulb will turn off due to the extra light. It would take a long time to charge them with this method. It isn’t practical to recharge the lights this way.

What Batteries do Solar Lights Use?

The most common batteries used for solar lights are NiMH and NiCd batteries. Both of these batteries can store a lot of energy for their size. They can also handle a lot of charging cycles and still store electricity.

NiMH is the newer, longer-lasting, and more versatile battery. It can produce more power longer for outdoor solar lighting and solar flood light units. 

How Long does it Take to Charge a Solar Light?

A solar lighting system can take up to six hours to charge. Decorative solar string lights can charge much quicker because they need less electricity to run. More powerful lights like a solar spotlight or flood lights can take the whole time.

The type of battery can also affect how long it takes to charge. NiMH charges much faster. Some of the better NiMH batteries can fill up in less than three hours. NiCd tends to take the most time and might need up to eight hours for a full charge.

Once charged, the lights can last between a few hours and up to eight hours. Depending on the batteries and the light’s output, it can last longer.

Why are My Solar Lights Not Working?

There are a few reasons a solar light may not be working. Troubleshooting some of these issues is very easy. 

  • Check the Solar Panel. If it is dirty, it may not be getting enough sunlight. Clean the panel and see if that fixes it. 
  • Make sure the light is free from artificial light at night. It won’t turn on if it is too bright. 
  • You can also check the solar battery. These can stop holding a charge, and then the solar light will stop turning on at night. 


There are a lot of systems involved in answering the question, how do solar lights work?

Solar panels have to collect sunlight and turn it into solar energy that a battery can store. Then when the sunlight stops shining, the photoresistors and control boards have to turn on the light. 

Whether you need solar path lights or decorative yard light, there are plenty of lighting options to help you out. It is easy to find a solar light fixture that works best for your needs and saves electricity.