Solar street lights are the most functional outdoor lighting system that work automatically from dusk till dawn and use only green and renewable solar energy for their operation. The latest technologies have made solar street lights more practical, attainable and affordable. The main components of a solar street light are solar panel, light source, rechargeable battery, charge controller and interconnecting cables.
The key role of a solar panel composed of multiple solar cells is to absorb solar energy and convert it into usable electricity to illuminate the solar street light. This process is called the photovoltaic effect. The performance of a solar street light majorly depends on the type and wattage of solar panels and the amount of electricity generated is determined by the size of the solar cells. Polycrystalline or monocrystalline solar panels are commonly used in solar street lights. The mounting position and the area of installation also can affect the panel efficiency. Solar panels have the best conversion rate when they are placed in such a way that sufficient direct sunlight strikes the panels throughout the day. Solar panels mostly have a lifespan of around 25 to 30 years.
The main purpose of a battery in a solar street light system is to store the converted electric energy so that this power can be used at night to illuminate the light source. Modern solar street lights use either lithium ion or LiFePO4 batteries. Both these batteries are well known for their backup capacity and durability. The fact that lithium batteries are lightweight and compact makes them the perfect choice for solar street lights. Batteries with good storage capacity can help the solar street lights to continue lighting up even on rainy days when there is not enough sunlight to convert. Unlike lead acid batteries, lithium batteries do not demand any maintenance and knowing the type, total amperage hours and voltage of the battery can help you choose the right light.
The converted electricity gets stored in the battery via the controller. A controller protects the battery from overcharging or undercharging. When the charging process comes to a halt at dusk, the controller prevents backflow of electricity from the battery through the solar cells. PWM and MPPT are the charge controllers commonly used in a solar street light unit. Controllers offer multistage charging and are able to convert excess voltage into amperage which extends the battery life. Understanding the type of charge controller used in your solar street light will help you understand their capabilities and functions better.
The photoreceptors within the lamp sense when the conversion process stops and turn on the light using the electricity stored in the battery. LED is the most common light source used now as it consumes less energy compared to fluorescent and incandescent lamps. LED lights are becoming more and more popular in solar light applications as they do not burn out and emit zero ultraviolet rays. The LED technology helps the lamps to deliver much higher lumens using less energy. LED light fixtures are less prone to failures and offer around 50,000 working hours. They create a pollution-free ambiance and do not produce much heat in the form of infrared radiation. The luminosity per watt and the light distribution pattern of the LED need to be considered while purchasing your solar street light.
The luminary is housed in durable ABS and aluminum alloy with IP65 waterproofing to sustain harsh weather conditions. The working principle of all in one and integrated solar street lights is the same; however, the working pattern of these lights is different. While some of the lights work with motions sensors, others have timer-based dimming options. The panels should be fixed separately if it is an integrated solar street light and the panel and the luminary are connected with the help of the cables given. Solar panels do not require separate installation as all the components are integrated together in all in one solar street lights.