How to purchase solar street light properly?
There is no uniform standard in the solar energy market. Is it true and false？How to buy suitable solar lamps?
Solar street lights consist of solar panels, batteries, and controllers and LED lamp.
Solar panels are divided into Monocrystal silicon and polycrystalline silicon. The conversion efficiency of single crystal silicon is 21% higher, and the conversion efficiency of polycrystalline silicon is lower which is only 15%~16%. But when it comes to power, 100W monocrystalline silicon and 100W polycrystalline silicon are a concept, but the area of polycrystalline silicon will be larger.
The battery is divided into a traditional lead-acid gel maintenance-free battery and lithium battery. Lead-acid batteries, conventional batteries, life cycle is not as good as lithium batteries, usually only one or two years lifetime, while having memory, can not be 100% discharge, only 75% of the depth of discharge, is not recommended now.
Lithium batteries are divided into lithium iron phosphate batteries and ternary lithium batteries, and the cost of lithium iron phosphate batteries is higher than that of ternary lithium.
However, LiFePO4 has excellent charge and discharge performance, many cycles, long service life, and high temperature stability. It will start to decompose at 700-800 °C and has high safety performance. Disadvantages: Performance is greatly affected by temperature, especially in low temperature environments, discharge capacity and capacity are greatly reduced, and its energy density is low.
Li-ion lithium, advantages: performance is less affected by temperature, low temperature resistance, can be used in low temperature environment of minus 15 degrees to 30 degrees. Disadvantages: The number of cycles is short, and the service life is short compared to lithium iron phosphate. At the same time, the safety and stability are poor, and the high temperature is easily decomposed, thereby causing a deflagration phenomenon.
The controller is divided into an MPPT controller and a PWM controller. The pulse width modulation PMW controller controls the analog circuit with the digital output of the microprocessor. This is a method of digitally encoding the analog signal level.
The cost of the MPPT controller is higher than the cost of the PWM controller. The MPPT controller can detect the generated voltage of the solar panel in real time and track the highest voltage and current value (VI), so that the system can charge the battery with the highest efficiency. The tracking method is completely automatic and does not require user adjustment. When the maximum power point of the solar panel changes with environmental conditions, the controller automatically tracks the maximum power point of the solar panel, ensuring that the maximum energy of the day is obtained from it, and the system efficiency is effectively improved.