Illumination is one of the solutions we all seek whenever we want to improve mobility and security at night. Property owners will install automatic street light using solar panel to brighten up their streets and create a daytime experience.  Commercial buildings use street light systems to light up their parking yards and compounds to improve surveillance.

The green energy movement has brought about a shift in the industry where the street lights get their power from energy from the sun. Solar energy is a reliable and efficient power source, and for decades it has become the best alternative for the traditional source.

The rise in the installation of solar-powered streetlights is a good indicator that with the right equipment, knowledge, and skill, anyone can design and construct one. In this article, we will go a step ahead and learn how to design and construct an automatic street light using a solar panel.

An automatic solar powered street light is different from the standard solar street light in terms of power control. An automatic system allows the luminaries to switch on and off on its own. The standard set up requires manual activation and due to human error, the person in charge forgets to switch it off. The use of automation in street light systems reduces energy consumption.

If you wish to design and construction of automatic street light, then let’s first take a look at how to design one.

Design of automatic street light using solar panel:

For starters, you will need a solar panel, luminaires, switching unit, battery, charge controllers, an inverter, a pole, and some wires or cables.

An automatic street light using solar panels have the following features:

  • The system turns the luminaries on at dusk and turns it off at dawn
  • The system will automatically start charging the battery after the luminaries are off

The size of the battery depends on the amount of power required to produce the light at the required brightness for the set period. On the other hand, the size of the solar panel depends on the power requirement (wattage), efficiency (conversion rate), solar irradiance received, and the climatic temperature of the location.

As for the charge controllers or regulators, their names suggest that they are used to control and regulate the flow of current into the batteries, ensuring that it maintains its maximum charging capacity. They also protect the battery from overcharging and overheating. Modern controllers come with sophisticated technologies such as the maximum power point tracker (MPPT) and Pulse width modulation (PWM), which can adjust the charging rate depending on the battery level.

Since energy stored in the battery is in the form of Direct Current (DC), you will need an inverter to convert it to Alternating Current (AC). You’ll determine the length of your pole by considering the illumination intensity and the shade of the area. On the other hand, the size and length of your interconnecting cable rely on the amount of current required and the distance between the components, respectively.

There are different types of luminaries you can choose from, such as LED lighting, incandescent, gas discharge, discharge, and metal halide lamps. The Automation of a solar-powered street light starts and ends at the switching unit. You will have to connect a  control circuit to the switch so that the system can operate by the presence and absence of the sun.

At dusk, the light-sensing circuit will allow the current to flow from the battery to the luminaries, while at dawn, it closes the path to charge the battery. To achieve this automatic function, you will need a transistor and a sensor mechanism known as Light Dependent Resistor (LDR) or a photodiode or phototransistor.

The theoretical concept of the LDR is that it is a photoresistor (works as a sensor and resistor) at the same time. Its resistance varies depending on the light that falls on its surface; the presence of light reduces the resistance and vice versa. It is the increase in resistance caused by an increase in the darkness that develops a threshold voltage that activates the transistor.

Construction of automatic street light using a solar panel

The construction stage is all about putting the design plan into action.  It includes mounting the hardware and developing the base of the solar street light system. During the assembly process, your main focus should be to create a full-functioning automatic switching circuit. You should also build housings for the various components and provide insulation for electrical components.

Before you mount your components on the pole and fix the unit into the foundation, you’ll need to do an experimental setup to verify that your system works. This testing process will help you verify the working condition of each component. After testing, you should be able to determine if the system is reliable in the supply of sufficient light at night.

After the experimental setup, you can then mount the solar panel at the top and the lighting fixture below it, taking into consideration their required heights. The solar module fixture mounting should not be permanent since you will need to adjust it to get the right angle of tilt.

The assembly of the components for your solar streetlight system should start from the ground, and then the wiring will follow afterward. No programming is required when constructing the cutoff circuit; all you need is a bit of electrical knowledge and skills to place the resistors and transistors correctly in the switch unit.

You will need more assistance in the construction phase, especially where you will have to lift the complete solar street light unit. You will need some support equipment and fastening tools to mount the main components on the pole and place the poles with the solar street light components in the foundation.

Therefore, this is all about the design and construction of automatic street light using solar panels. In the end, you will be able to save and efficiently conserve energy using the automatic function.