1. Selection of light source
Most lawn lamps use LED as the light source. The LED has a long life, can reach more than 100,000h, and has a low working voltage. It is very suitable for use in solar lawn lamps. In particular, LED technology has made a key breakthrough, and its characteristics have greatly improved in the past 5 years. At the same time, the performance-price ratio has also been greatly improved. In addition, LED uses low voltage DC power supply, its light source control cost is low, it is possible to adjust the light and dark, frequent switching, and will not adversely affect the performance of the LED. LED can also control the color, change the light distribution, and generate dynamic illusion, so it is particularly suitable for application in solar lawn lights. However, LEDs have many inherent characteristics, and there will be undesirable consequences if you are not careful when using them. At present, the highest luminous efficiency of LEDs on the market can only reach 30Lm/W, which is only 1/2 of the three primary color energy-saving lamps, and the luminous efficiency of the three primary color energy-saving lamps can reach 50-80Lm-W. Compared with the two light sources, the current cost per lumen is quite different. From the service life point of view, the life span of the three primary color energy-saving lamps (including electronic ballasts) can reach 6000h, and the LED can reach more than 100,000h. On the surface, the LED life is a few of the three primary color energy-saving lamps (including electronic ballasts). Ten times, but this is not the case. At present, most solar lawn lights use ultra-high-brightness white LEDs, and the time (lifetime) at which the luminous flux maintenance rate reaches 50% of the initial brightness at a current of 20mA is less than 10000h. The electric light source institute of Fudan University once proved the above argument. This argument shows that LED is not the best solar light source in many cases at present, unless it is applied to low-end solar lawn lights with a service life of only 1-2 years, or solar lawn lights below 1W. For solar lamps above 1W, it is best to use three primary colors of high-efficiency energy-saving light sources. At present, some solar lawn lights use 30-40 ultra-bright white LEDs with an input power of more than 2W. In this case, if you use a three-color high-efficiency energy-saving lamp, the price is only 1/10 of the LED, and the luminous flux is twice that of the original. What's even more gratifying is that the low-voltage DC three-color high-efficiency energy-saving lamp with 2-10W has been successfully developed, and the life span can reach 6000h.
Installation angle of solar cell and light transmittance of lampshade
2. Many solar lamp production plants place the solar cells horizontally for aesthetics. In this case, the output power of the solar cells will be reduced by 15%-20%. If a decorative cover is added to the solar cells, the output of the solar cells The power will be reduced by about 5% again. Solar cells are expensive, and we have collected information on many foreign solar lamps. Most of them choose between energy saving and energy saving. The optimal tilt angle for using solar cells in the lower reaches of the Yangtze River is about 40°, and the direction is right south. For solar lawn lights that must be decorated with solar cells or courtyard lights that need to be covered with light sources, the light transmission performance of the cover and the resistance to ultraviolet aging in sunlight must be considered. The following table shows the light transmittance of various commonly used materials, and should be fully considered from the perspective of energy saving when designing solar cells and lampshades.
Boost circuit and matching efficiency issues
3. Low-power solar lawn lamps generally have a booster circuit. At present, various manufacturers use an oscillator circuit to boost the inductor. The standard color code inductor is used for the inductor. The standard color code inductor uses an open magnetic circuit, and the magnetic flux loss is large, so the circuit efficiency is low. If a closed magnetic circuit is used to make an inductive boost, such as a magnetic ring, the efficiency of the boost circuit will be greatly improved. We used φ10 magnetic ring to make inductance, and carried out the control experiment under the same conditions. The comparison sample was a low-power solar lawn lamp. As a result, the efficiency of using a closed magnetic circuit to make an inductor is 20%-40% higher than that using a standard color-coded inductor.
The price
4. Many users only choose cheaper ones for the price of solar street lights. In fact, this is wrong.