Solar lights do not need direct sunlight to work. The amount of sunlight determines how much energy the solar panels convert, which is then stored in a battery. If your solar outdoor lights do not receive enough sunlight, they will not run as long.

Outdoor solar lights can still operate without direct sunlight. By changing their position, cleaning them frequently, and checking the batteries, you may gain more illumination during the night. Here is a closer look at how solar lights work without the sun and what you can do about it.

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How Do Solar Lights Charge Without Sun?

How Do Solar Lights Charge Without Sun?

Solar lighting devices, including solar lamps and solar yard lights, operate at maximum efficiency when the sun is shining directly on the solar cells. On cloudy, overcast days, the solar panels are less efficient and convert less solar energy.

A solar-powered light relies on several components to charge during the day and provide light during the night:

  • Solar panel cells
  • Rechargeable battery
  • Light sensor

Without the sun, a solar light may not fully charge, which limits the battery life available for powering the LED bulbs in the evening.

The Solar Panel

A solar-powered garden light includes a solar panel with multiple solar cells. Each solar cell has multiple layers of crystalline silicone and various chemicals.

The layers inside the solar cells contain positively charged spaces and negatively charged electrons. Sunlight passes through the solar cells, which pushes the electrons into the positively charged spaces.

The electrons are transferred as a direct current of electricity. The electricity passes through wires connected from the solar panel to a circuit board inside the enclosure of the solar light.

As the sunlight weakens through the evening or as clouds pass, the solar panels press fewer electrons into the positively charged spaces. Less energy then passes from the solar panel to the battery.

The Battery

The energy passes to a circuit board that controls the charging of the solar light battery. Most outdoor solar lighting includes lithium batteries. The capacity of the battery is measured in amp-hours.

The rechargeable battery used in the typical solar path light may have a capacity between 300 milliamps-hour (mAh) to 1200 mAh. A larger capacity allows the battery to hold more energy. However, without adequate sunlight, it may not receive a full charge.

The Light Sensor

A light sensor, which is typically a simple photoreceptor, is used to detect light. When nighttime arrives, the photoreceptor tells the circuit board to turn on the LED bulb.

Some lights also include a motion sensor to activate the LED light. If the photoreceptor becomes covered in dirt or obstructed by grass or plants, it may trigger the LED bulb during the daytime.

How Do Solar Lights Work in the Shade?

Solar lights still receive sunlight when placed in a shaded area but may not work as efficiently. The solar cell receives less light, which limits the conversion of sunlight to electricity.

The battery continues to charge throughout the day. However, when placed in the shade, the battery may not contain as much energy by the time that night arrives.

What Is the Optimum Position for Solar Lights?

Solar lights should be placed in an unobstructed area with access to direct sunlight for optimal efficiency. Solar panels also tend to work best when placed at an angle of 45 degrees to 60 degrees.

Placement is less of a concern with path lights compared to a solar street light or a security light. Other types of outdoor lighting are often installed on exterior walls, which may limit exposure to the sun during certain times of the day.

How Much Sunlight Does a Solar Light Need to Stay on All Night?

Most outdoor solar lights need at least eight hours of sunlight to stay on all night. However, the duration depends on the light setting. Using a low light mode allows the lights to stay on longer.

How to Get More Sunlight to Your Panels

Using mirrors allows you to redirect sunlight to your panels. Unfortunately, mirrors may not be an attractive addition to your yard. It is also difficult to position a mirror near a string light or other decorative lights affixed to exterior walls or fences.

Other options include trying different positions for your solar landscape light fixtures around the yard, adjusting the angle of the solar panels, and making sure that you keep the solar panels clean.

Different Positions for Solar Lights

If the previous recommendations do not help power your solar garden light, try moving the yard lights to different positions around the yard. You may find a spot that receives less shade. You should also ensure that the outdoor light fixtures are not blocked by nearby objects, such as tall grass or plants.

Clean Your Solar Panels

If the solar panels get dirty, they do not receive as much sunlight. Rain can cause mud and debris to collect on the surface of the panels. To keep your panels working efficiently, occasionally wipe them clean with mild soap and water.

Change the Batteries

Along with cleaning the solar panels, you may need to occasionally change the batteries. Rechargeable batteries gradually lose their ability to hold a charge. Even with direct sunlight, the solar battery may not gain enough of a charge to power the lights all night.


Solar lights do not need direct sunlight to work. However, the amount of light determines the amount of power contained in the battery. If your solar lights only receive indirect sunlight, they are less likely to provide illumination during the night.

Keep your outdoor spaces illuminated by choosing the right location for your solar spotlight or fairy lights. You should also keep them clean and may need to replace the batteries occasionally.