How Solar Lights Work

Solar Light Components:

• The Case
• Solar Cell Panel
• Controller Board
• LED Light
• AA NiCad batteries
• Photo Resistor
• Diode

A single solar cell panel produces a maximum of 0.45 volts and a varying amount of current depending on the size of the panel and the amount of sun light the solar panel receives. In a typical solar yard light there is four solar cells attached together, and will produce around 1.8 volts and a maximum of about 100 milliamps in full sunlight.

The solar cells wired directly to the battery through a diode (which prevents the battery's current from flowing back through the solar cell at night). The battery is a completely standard AA NiCad battery. These batteries produce about 1.2 volts and can store a maximum of approximately 700 milliamp-hours. During the day, the battery charges, reaching maximum charge except on shorter winter days or days when there is heavy overcast. At night, the solar cells stop producing power. The photo resistor turns on the LED light.

The controller board accepts power from the solar cell and battery, as well as input from the photo resistor. It has a three-transistor circuit that turns on the LED when the photo resistor indicates darkness. The LED draws about 45 milliamps with the battery producing about 1.23 volts (0.055 watts). The NiCad battery, when fully charged, can operate the LED for about 8-12 hours.

Almost all-solar yard lights use LED's as their light source. An LED is a light emitting diode. It is not really a light bulb but an electrical component that emits light. These electrical components proven highly reliable, giving off almost no heat and have a life expectancy of up to 20 years.
Controller Board
Solar Cell PanelSolar lights will work in most areas; however solar lights will work well only as long as the solar cells receive the manufacturers recommended hours of sunlight. Solar lights located in places that receive less sunlight than the solar cells needs, will operate for fewer hours per night than expected. Shading of the solar cells by landscape features, such as vegetation, buildings, etc will also affect battery charging and performance. There is virtually no maintenance required except for occasional cleaning of the panel surface to keep it free of dust and dirt, and replacing the batteries when required.