Solar street lights are the most effective outdoor lighting system, which function using clean and renewable solar energy. There is an increasing demand for energy-efficient lighting considering the challenges raised by global warming. As per recent studies, it has been observed that solar-powered lights can bring down greenhouse gas emissions by over 50% in comparison with traditional street lighting applications which can create up to 6% carbon dioxide emission. Solar industry is evolving rapidly and with the aim of making solar lights accessible to every household and business, studies are being conducted to improve solar efficiency and to make the components less expensive.
The main parts of a solar street light system are:
- Solar panel: With suitable inclination to receive maximum direct sunlight throughout the day, solar panels are fixed on top of the pole. Solar panels produce direct current using solar energy, which is used to charge the battery. Mono-crystalline or poly-crystalline solar panels are typically used in a solar street lighting system.
- LED lamp: In the modern solar street lights, the controller and the battery are incorporated in the luminary itself. Fluorescent and incandescent lamps were used in traditional solar street lights but the LED technology is well known to use less energy and lasts longer with zero UV emissions.
- Charge controller: A charge controller’s main function is to increases the battery life by not allowing the battery to overcharge or deep discharge. It works as a regulator by turning off the light during deep discharge and disconnects the PV module during overcharge conditions. PWM or MPPT is the commonly used charge controller in solar street lights
- Battery: The energy generated by solar panels is stored in the battery which is used to light up the LED during night time. Traditionally, lead acid batteries were used in solar street lights. The latest lights use either lithium-ion or LiFePO4 batteries considering their small size and high efficiency along with multiple other advantages.
- Interconnecting wires: Very minimal wiring is required to connect solar panels, luminary and battery during installation.
- Pole: Thermally galvanized steel poles can go without rusting for close to 40 years. The poles are treated and preserved properly before being used to withstand all types of rough weather conditions.
- Energy saving
- Pollution reducing
- No cable work
- Money saving
- Easy installation and maintenance
- Motion sensor and dimming
1. All-in-one solar street light: In this type of light, solar panel, controller, battery and LED are integrated into a single unit. These lights switch on at dusk and after a few seconds’ delay, they automatically go down to 20% brightness. The motion sensors in these lights detect movement and electronically increase the brightness to 100%. After a time delay, if no motion is detected, the light gets adjusted back to 20% brightness.
2. Integrated solar street light: Solar panel comes as a separate unit and battery, controller and luminary are molded into a single unit. Model-I integrated solar street lights remain at full brightness from dusk to dawn. Model-II integrated solar street lights operate at 100% brightness in the first four hours and then at a lower level for the rest of the night.
3. Semi-integrated solar street light: This traditional device is not very common now, where luminary, lighting source and controller were housed into a single unit with external solar panel and battery box.
Solar Street Light Applications
Solar street lights are used to provide security in urban and remote areas with no access to conventional grid electricity. They increase the safety of drivers and pedestrians who use the public spaces past the daylight hours. Along with promoting security, they also improve the quality of life in rural areas. Solar street lights are also being added as a decorative feature in residential properties. A few of the main applications are:
- Street Lighting
- Park Lighting
- Roadway Lighting
- Gate Lighting
- Pathway Lighting
- Yard Lighting
- Ramp Lighting
- Fence Lighting
- Sidewalk Lighting
- Campus Lighting
- Private Road Lighting
- Boat Dock Lighting
- Farm and Ranch Lighting
- Remote Area Lighting
- Wildlife Area Lighting
- Military Base Lighting
- Runway Lighting
- Perimeter Security Lighting
- Jogging and Bike Path Lighting
Installation and maintenance
The installation of solar street lights is quite unchallenging and uncomplicated in comparison to the conventional street lights. The luminary and panel are fixed to the top of the pole before hoisting the pole using basic tools. Once the pole is pulled upright, it is secured to the ground using concrete. One must pay attention to the fact that the panel is tilted at an angle and the solar street light should be placed at an area where maximum direct sunlight falls on the panel throughout the day.
There is almost no maintenance required after installation; however, you may check the panels once in a while to clean them off leaves, dust or snow. Cleaner solar panels can guarantee longevity of the panels. Most of the dirt is washed off during rains. Frequent inspection of the solar fixture can be conducted to look for any problems related to vandalism, weather or wildlife. If required, the components can be cleaned with a soft bristled brush or cloth or you can also wash off the dirt using a jet spray.
- Power outage will not affect areas with solar street lights
- Works in cloudy or rainy days with battery backup
- Easy installation
- No maintenance required
- No operational costs
- Saves money as the light works purely on free solar energy
- Solar modules with warranty up to 25 years
- Eco-friendly and helps in eliminating pollution
- Infra-sensory lights that automatically switch off during the day and turn on at dusk after recharging.
- LED lights with cool and warm light options and work without flickering and with higher brightness compared to sodium lights
- Rust-proof, waterproof and shock-proof
Solar street lights are available in different sizes, features and designs. Consulting a professional from the solar industry will help you decide which solar street light is best suited for your requirements.