In the design of solar street lights, solar garden lights, and LED street lights, there are many factors involved in the light source, solar cell system, and battery charge and discharge control. Problems in any of them will cause product defects.
Let us first understand the composition of solar lamps!
1. Solar panels
2. Solar charge and discharge controller
3. Solar energy storage battery
4. Load
5. Lamp housing
The following are respectively introduced:
1. Solar panels
The main function of solar cells is to convert light energy into electrical energy, a phenomenon called photovoltaic effect. Among many solar cells, the most common and practical ones are monocrystalline silicon solar cells, polycrystalline silicon solar cells and amorphous silicon solar cells. In the eastern and western regions with sufficient sunlight, 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 monocrystalline silicon cells, and the conversion efficiency has been continuously improved in recent years. In the southern region where there are more rainy days and relatively less 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.
Solar cells have five electrical performance parameters:
1. Isc is the short-circuit current
2. Im is the peak current
3. Voc is the open circuit voltage
4. Vm is the peak voltage
5. Pm is the peak power
Note: Pm is the peak power = Im is the peak current × Vm is the peak voltage.
For monolithic solar cells, 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 modules used in solar lighting fixtures are composed of multiple solar cells connected.
2. Solar 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, since 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 must be It is more complicated than the control of 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 well-performing charge-discharge control circuit, it is impossible to have a well-performing solar luminaire. The charge and discharge controller must have the following characteristics:
1. Anti-reverse charging control
2. Anti-overcharge control
3. Anti-overdischarge control
4. Temperature compensation
3. Solar energy storage battery
Since the input energy of the solar photovoltaic power generation system is not stable enough, 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. If the capacity of the battery is too small, it cannot meet the needs of night lighting or continuous use; if the capacity of the battery is too large, and the battery board cannot provide enough charging current, the battery is often in a state of power deficit, which affects the life of the battery and causes waste.
4. Load
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 lamps, 12V 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 lights or 12V DC energy-saving lamps. The voltage of DC energy-saving lamps is DC, which is convenient and safe without inverter.
Street lights generally use 12V DC energy-saving lamps and low-voltage sodium lamps. Low-voltage sodium lamps have high efficiency but are relatively expensive, and are used less frequently. Our company adopts self-developed new LED street lights and has four national patents.
5. LED lamp housing
We have collected a lot of information on foreign solar lamps. Between aesthetics and energy saving, most of them choose energy saving. The appearance requirements of lamps and lanterns are not very high, and they are relatively practical. At present, many manufacturers have beautiful appearance and choose stainless steel casing. But what about performance? This is worth thinking about!
In summary, when choosing a solar street light that suits you, in addition to the energy-saving and environmental protection features of the product itself, you should also focus on the use stability and product economy of the product.
Post time: Nov-05-2022