How to buy solar street light and other lamps?
In the design of solar street light and other lighting fixtures, many factors, such as light source, solar cell system, battery charge and discharge control, etc., any of which may cause product defects. Solar luminaires consist of five components: solar panels, charge and discharge controllers, batteries, loads, and luminaire housings. Below, let's take a look at it one by one.
1. solar battery
The main function of solar cells is to convert light energy into electrical energy. This phenomenon is called the photovoltaic effect. Among the many solar cells, three solar cells, such as single crystal silicon, polycrystalline silicon and amorphous silicon, are more common and practical. It is better to use polycrystalline silicon solar cells in the eastern and western regions where there is plenty of sunlight and sunshine. Due to the relatively simple production process of polycrystalline silicon solar cells, the price is lower than a single crystal, and the conversion efficiency is continuously improved. In the southern part of the rainy days, the sun is relatively insufficient, the use of single crystal silicon solar cells is better because the electrical performance parameters of monocrystalline silicon solar cells are relatively stable. Amorphous silicon solar cells are better indoors where sunlight is weak because amorphous silicon solar cells require less sunlight.
First of all, we must first understand the solar cells of any solar lighting products. The solar cells have five electrical performance parameters, namely: short-circuit current, peak current, open circuit voltage, peak voltage, and peak power.
For the average user, how do we know the five parameter values? Teach you a simple way, let us know this parameter relatively, we can test these five parameters with a universal meter at 12 noon.
For a single-chip solar cell, it is a PN junction that has all the properties of a PN junction in addition to the ability to generate electricity when it is illuminated by sunlight. Its rated output voltage is 0.48V under standard lighting conditions. The solar cell modules used in solar lighting fixtures are all made up of multiple solar cell connections.
Users can look at the solar cell first to understand the price, performance and stability of solar lighting. Below I will introduce the charge and discharge controller, load, battery, etc.
2. charge and discharge controller
Regardless of the size of the solar luminaire, a good performance charge and discharge control circuit is essential. In order to extend the service life of the battery, its charging and discharging conditions must be limited to prevent overcharging and deep discharge of the battery. In addition, since the input energy of the solar photovoltaic power generation system is extremely unstable, the control of charging the battery in the photovoltaic power generation system is more complicated than the control of the ordinary battery charging. For the design of solar luminaires, success and failure often depend on the success and failure of the charge and discharge control circuit.
Without a good charge and discharge control circuit, it is impossible to have a good performance solar luminaire. The charge and discharge controller must have the following characteristics: anti-reverse charge control, anti-overcharge control, over-discharge prevention control, and temperature compensation.
Since 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 the solar light fixture is no exception, and the battery must be configured to work. The choice of battery capacity generally follows the following principles: First, the energy of the daytime solar cell module is stored as much as possible while meeting the nighttime illumination, and at the same time, it is also possible to store the electric energy required for the nighttime illumination of the continuous rainy day. 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 deficient state, which affects the battery life and causes waste.
Solar lighting products have the advantage of energy saving and environmental protection. Of course, the load needs to be energy-saving and has a long service life. We generally use led DC energy-saving lamps and low-pressure sodium lamps.
At present, most lawn lamps use LED as a light source. The LED has a long service life and can reach more than 100000h, and the working voltage is low, which is very suitable for application on solar lawn lamps.
Garden lights generally use led and DC energy-saving lamps. The DC energy-saving lamp voltage is DC, no need to invert, convenient and safe.
Street lamps generally use low-pressure sodium lamps. Low-pressure sodium lighting is high (up to 200 LM/W) but low-pressure sodium lamps are more expensive.
5. Lamp housing
We have collected a lot of foreign solar light data, and between beauty and energy saving, most choose energy saving. The appearance of the luminaire should not be very high, so it is relatively practical. At present, there are many lamps in China that look very beautiful and are made of stainless steel. But what about performance? This makes us think again!
The key to a good solar lighting product is system design. What is a reasonable system design? Let us first understand the several important factors affecting the system, namely the total annual radiation, the longest days without sunshine, the daily power consumption and the average sunshine hours on the latitude and solar array.
Let us think about it: If the solar battery is not fully charged, what will happen to the daily discharge? Can the system still be illuminated on a rainy day for several years? These problems must be taken seriously by our designers.
Finally, I will introduce a simple method for judging the performance of solar lighting systems: First, the solar cell power must be more than 4 times higher than the load power, and the system can work normally. Second, the battery capacity must be more than 4 times higher than the daily power consumption of the load (western region), and the southern region should be more than 6 times higher.