(1) photosensitive sensor. Solar lawn lights require a light-controlled switch, and designers often use photosensitive resistors to turn the lights on and off automatically. In fact, solar cells themselves are excellent photosensitive sensors. For a solar lawn lamp that only USES a 1.2vni-cd battery, the solar cell module consists of four solar cells in series, and the voltage is lower under weak light, so that the voltage is lower than 0.7v when the sky is dark, causing the light-controlled switch to fail. In this case, the problem can be solved by adding a transistor directly coupled to the amplifier.
(2) control the load according to the battery voltage. Solar lawn lamps often require a high duration of continuous rain, which increases system costs. We can reduce the system cost by reducing the number of LED connections when the battery voltage drops continuously in rainy weather, or by reducing the daily luminous time of solar lawn lights.
(3) package form of solar cell. At present, there are two main forms of solar cell packaging, laminating and dropping glue. Laminating process can guarantee the working life of solar cells more than 25 years. Although the dripping glue was beautiful at that time, the working life of solar cells is only 1-2 years. Therefore, for solar lawn lamps with low power under 1W, the form of drip encapsulation can be used without excessive service life requirements. For solar lawn lamps with specified service life, laminating encapsulation is recommended.
(4) flicker to light. On the one hand, it can increase the solar lawn irradiation effect; on the other hand, it can control the average output current of the battery by changing the scintillation duty ratio to extend the working time of the system; or, under the same conditions, it can reduce the power of the solar cell, and the cost will be greatly reduced.
(5) switching speed of efficient energy saving lamp based on three colors. This problem is very important, and it even determines the service life of the solar lawn lamp. When the three-color base color efficient energy saving lamp is started, the starting current is as high as 10-20 times, and the voltage of the system may drop significantly under such a large current. The solar lawn lamp cannot be started or started repeatedly until it is damaged.
(6) improve the efficiency of booster circuit and influence on LED lamp. Low power solar lawn lamp generally has a booster circuit, if the use of oscillation circuit, inductance booster. The inductor adopts standard color code inductor. Open magnetic circuit is used in standard color code inductor, so the circuit efficiency is low. If a closed magnetic circuit is used to make an inductance booster, such as a magnetic ring, the efficiency of the booster circuit will be greatly improved. The characteristics of LED are close to the stable voltage diode, the working voltage varies by 0.1v, and the working current may vary by about 20mA. In order to be safe, series current limiting resistor is used under normal circumstances. The great energy loss is obviously not suitable for solar lawn lamps, and the LED brightness varies with the working voltage, and it must be automatic current limiting, otherwise the LED will be damaged. The peak current of general LED is 50-100ma, the reverse connection of anti-high energy battery or the battery is not loaded, when the peak voltage of booster circuit is too high, it is likely to exceed this limit and damage the LED.