Solar LED street lights use the photovoltaic effect principle of solar cells. During the day, the solar cell absorbs solar energy to generate electricity, which is stored in the battery through the photovoltaic controller. When night falls or the light around the lamp is low, the energy stored in the battery will power the light source through the photovoltaic controller. After the set time is up The controller cuts off the power to the light source. Solar energy
LED street lights are composed of the following parts: solar panels, solar LED street light controllers, batteries, light sources, light poles and lamp housings, etc. The structure diagram of solar LED street lights is shown in Figure 1.
Solar panels are the core part of solar LED street lights and the most valuable part of solar LED street lights. Its function is to convert the sun’s radiant energy into electrical energy. Among the many solar cells that are more common and practical, there are three types of monocrystalline silicon solar cells, polycrystalline silicon solar cells and amorphous silicon solar cells. In the eastern and western regions with sufficient sunlight and good sunlight, it is better to use polycrystalline silicon solar cells, because the production process of polycrystalline silicon solar cells is relatively simple and the price is lower than that of monocrystalline silicon. In southern regions where there are more cloudy and rainy days and relatively insufficient sunlight, it is better to use monocrystalline silicon solar cells because the performance parameters of monocrystalline silicon solar cells are relatively stable.
②Solar LED street light controller
Regardless of the size of solar lamps, a good performance charge and discharge controller is essential. In order to prolong the service life of the battery, its charging and discharging conditions must be restricted to prevent the battery from overcharging and deep discharge. In places with large temperature differences, a qualified controller should also have temperature compensation. At the same time, the solar controller should have both street lamp control functions, light control, time control functions, and automatic load control at night, which is convenient for extending the working time of solar LED street lights in rainy days.
For any solar lighting system, the pros and cons of the charge and discharge control circuit will directly affect the success of the system application. Since the input energy of the photovoltaic power generation part of the solar LED street lamp is extremely unstable, the control of battery charging is better than using The mains charger is complicated to control the battery charging. A good-performance photovoltaic controller should have multiple protections such as controlling battery charging and discharging, temperature regulation, maximum power tracking and overcharge protection, overdischarge protection, short circuit protection, reverse connection protection, etc. Function, automatic switch and time adjustment function, so as to ensure the reliable operation of the system. At the same time, the photovoltaic controller should also have the function of enabling the solar cell components to intelligently output the maximum power under different temperatures and different solar radiation conditions, so that the solar photovoltaic system has Very high efficiency.
Since the battery charging of the solar photovoltaic system is directly provided by the solar battery, the energy obtained is extremely unstable, so a battery with a reasonable capacity and reliable performance should be configured to ensure the normal operation of the solar LED street light. Valve-regulated sealed lead-acid batteries are usually used in solar LED street lights. The valve-regulated sealed lead-acid battery adopts a fully sealed method with high discharge rate and stable characteristics; no need to add water; simple installation, small footprint, horizontal and vertical installation: the design life is generally 5 to 7 years. The general principle for selecting the battery capacity is: First, it can meet the lighting requirements at night, and store the energy generated by solar cell components during the day as much as possible, and at the same time, it can meet the electrical energy required for continuous rainy days and night lighting. The battery capacity is too small to meet the needs of night lighting, and the battery capacity is too large, and the battery is in a state of power loss for a long time, which will shorten the battery life and waste unnecessary investment.
A simple method can be used to determine the relationship between them, that is, the solar cell power must be more than 4 times higher than the load power for the system to work normally. The voltage of the solar cell must exceed the working voltage of the battery by 20%~30% to ensure the normal charging of the battery. The capacity of the battery must be more than 6 times higher than the daily consumption of the load.
The basic requirements of solar LED street lights for the battery pack used are: ⑴ Low self-discharge rate: ⑵ Long service life;⑶ Strong deep discharge capability; ⑷ High charging efficiency: ⑸ Less maintenance or maintenance-free: ⑹ Wide operating temperature range: ⑺ Low price Kang.
④Solar street light source
According to actual needs, solar street lights can be selected from a variety of light sources such as 12V DC energy-saving lamps, low-pressure sodium lamps, high-pressure sodium lamps, electrodeless electromagnetic induction lamps, LED lamps, etc. No matter which kind of light source is selected, its brightness is directly related to the power of the light source, and directly affects the system configuration and investment costs. Under the same lighting time conditions, the greater the power of the light source, the higher the brightness, and the higher the system configuration cost: the smaller the power, the lower the brightness, and the less system configuration costs. The light source used by solar street lamps is an important indicator of whether the solar lamps can be used normally. Generally, solar street lamps use low-voltage energy-saving lamps, low-pressure sodium lamps, induction lamps, and LED lamps.
⑤Light pole and lamp shell
The height of the light pole should be determined according to the width of the road, the distance between the lamps, and the illuminance standard of the road. The lamp generally refers to the part used to install the lighting source, which is commonly referred to as the lamp holder. Light poles are divided into various forms such as variable diameter poles, tapered poles, combined poles, etc., and are connected to the lamp through a pick arm. General light poles and lamps can be selected as solar LED street lights. If the solution of directly installing solar cell modules on the light pole is adopted, it is necessary to fabricate the solar cell module bracket according to the area of the solar cell module, and consider the wind resistance of the light pole. The choice of lamps and poles is wide, generally meeting the requirements of practicality and beauty.
⑥Cable and connection fastening accessories
Cables are used to connect solar cell modules, storage batteries, charge and discharge controllers, light sources and other devices. The wire diameter standard of the cable is determined by the system configuration, and the length of the cable is determined by the height of the light pole and the installation position of the device. The connection and fastening accessories are used to fix the input and output terminals of the connection of each device, and fix the light pole and the lamp.