Configuration and purchase of solar street lights

In the design of solar lighting fixtures, many factors are involved, such as light source, solar battery system, battery charge and discharge control, etc. Any problems in any of them will cause product defects. Solar lamps are composed of five parts: solar panels, charge and discharge controllers, batteries, loads and lamp housings. Solar cells The main function of solar cells is to convert light energy into electrical energy, a phenomenon called photovoltaic effect. Among the many solar cells, the most common and practical ones are monocrystalline silicon, polycrystalline silicon and amorphous silicon. In the eastern and western regions with sufficient sunlight and good sunshine, it is better to use polycrystalline silicon solar cells. Because the production process of polycrystalline silicon solar cells is relatively simple, the price is lower than that of single crystal, and the conversion efficiency is constantly improving. In the southern region where there are many cloudy and rainy days and relatively insufficient sunshine, it is better to use monocrystalline silicon solar cells, because the electrical performance parameters of monocrystalline silicon solar cells are relatively stable. Amorphous silicon solar cells are better in the case of weak indoor sunlight, because amorphous silicon solar cells have lower requirements for solar lighting conditions. First of all, for any solar lighting product, we must first understand solar cells. Solar cells have five electrical performance parameters, namely: short-circuit current, peak current, open-circuit voltage, peak voltage, and peak power. For ordinary users, how can we know its 5 parameter values? Teach you a simple method, let us know this parameter relatively, we can test these 5 parameters with a multimeter in the case of sunlight at 12:00 noon (of course, there will be a little error in the measured value). For a monolithic solar cell, it is a PN junction, which has all the characteristics of a PN junction except that it can generate electricity when sunlight shines on it. Under standard lighting conditions, it has a rated output voltage of 0.48V. The solar cell components used in solar lighting fixtures are composed of multiple pieces of solar cells connected together. Users can first look at solar cells to understand the price, performance and stability of solar lighting. Below I will introduce the charge and discharge controller, load, battery, etc. Charge and discharge controller Regardless of the size of solar lamps, a charge and discharge control circuit with good performance is essential. In order to prolong the service life of the battery, its charging and discharging conditions must be limited to prevent the battery from being overcharged and deeply discharged. In addition, because the input energy of the solar photovoltaic power generation system is extremely unstable, the control of the battery charging in the photovoltaic power generation system is more complicated than the control of the ordinary battery charging. For the design of solar lamps, success and failure often depend on the success and failure of the charge and discharge control circuit. Without a charge and discharge control circuit with good performance, it is impossible to have a solar lamp with good performance. The charge-discharge controller must have the following characteristics, namely: anti-reverse charge control, anti-overcharge control, anti-over-discharge control, and temperature compensation. Battery Because the input energy of the solar photovoltaic power generation system is extremely unstable, it is generally necessary to configure the battery system to work, and solar lamps are no exception, and the battery must be configured to work. Generally, there are lead-acid batteries, Ni-Cd batteries, and Ni-H batteries. Their capacity selection directly affects the reliability of the system and the price of the system. The selection of battery capacity generally follows the following principles: first, on the premise that it can meet the night lighting, the energy of the solar cell components during the day should be stored as much as possible, and at the same time, it should be able to store the electrical energy that meets the continuous cloudy and rainy night lighting needs. The battery capacity is too small to meet the needs of night lighting. If the storage capacity is too large, the battery is always in a state of power loss, affecting the life of the battery and causing waste. Load The solar lighting products have the advantages of energy saving and environmental protection. Of course, the load should be energy saving and have a long life. We generally use LED DC energy-saving lamps and low-pressure sodium lamps. At present, most lawn lamps use LED as the light source. The LED has a long service life, which can reach more than 100,000 hours, and has a low operating voltage, which is very suitable for use in solar lawn lamps. Garden lights generally use LED and DC energy-saving lamps. The voltage of DC energy-saving lamps is DC, which is convenient and safe without inverter. Street lights generally use low pressure sodium lamps. Low-pressure sodium lamps have high efficiency (up to 200LM/W), but low-pressure sodium lamps are relatively expensive. Lamp housing We have collected a lot of information on foreign solar lamps, and most of them choose energy saving between aesthetics and energy saving. The appearance requirements of lamps and lanterns are not very high, and they are relatively practical. At present, many lamps and lanterns in China are very beautiful in appearance, and stainless steel casings are used. But what about performance? This makes us think again! A good solar lighting product, the key lies in the system design, what is a reasonable system design? Then let us first understand several important factors that affect the system, which are latitude, annual total radiation on the solar phalanx, the longest no-sunshine days, daily power consumption and average sunshine hours. Let's think about it: if the solar battery is not charged enough, what will happen to the daily discharge capacity? Can the system still illuminate on cloudy and rainy days for several consecutive years? These issues should be taken seriously by our designers.