The cost ratio of the controller in the entire solar street light system is very low. Although it looks like an inconspicuous small object, it plays a very important role. If the choice is not good, the stability and service life of the entire system will be affected. It is greatly discounted, and a relatively mature controller can also reduce the cost of the entire system through functions and achieve the purpose of saving costs.

Below we will make a comparative analysis of some of the main performances of the conventional controller and the industrial version of the controller:

One: Exit the protection voltage

Some customers often find that after the solar street light is on for a period of time, especially after continuous cloudy and rainy days, the street light will not light for several days or even many days.

This question has puzzled many engineers. In fact, this is the problem of the voltage value of "exit under-voltage protection". The higher the value is set, the longer the recovery time after under-voltage, which will result in the failure of lighting for many days. lamp.

In this regard, the industrial version of the controller allows each customer to set the voltage value to exit the protection according to the configuration. However, it is worth noting that the configuration of the battery board must be reasonable. If the daily charge of the battery board cannot meet the discharge amount of the night, the battery is often in deep discharge in the long run, and the service life is greatly shortened, so the configuration of the battery board must be enlarged. , the larger the configuration of the battery board, the lower the voltage that exits the protection can be set, so that it will not affect the battery.

Two: LED light constant current output

Due to its own characteristics, LEDs must be constant current or current limited by technical means, otherwise they cannot be used normally. Common LED lights use an additional drive power supply to achieve constant current for the LED lights, but this drive accounts for about 10%-20% of the total power of the entire light, such as an LED light with a theoretical value of 42W, plus The actual power after driving may be around 46-50W. When calculating the power of the solar panel and the capacity of the battery, an extra 10%-20% must be added to meet the power consumption caused by the drive. In addition, adding more drivers will add another link that causes failures. The industrial version of the controller performs power-free constant current through software, with high stability and reduced overall power consumption.

Three: output period

Ordinary controllers can only be set to turn off the lights for several hours, such as 4 hours or 8 hours after turning on the lights, which can no longer meet the needs of many customers. The industrial version of the controller can be divided into 3 periods, the time of each period can be set arbitrarily, and each period can be set to a closed state according to the different use environments. For example, in some factories or scenic areas at night, the second time period (late night) can be closed, or both the second and third time periods can be closed to reduce the cost of use. [page]

Four: LED lamp output power adjustment

Among the lamps for solar energy applications, LED lamps are the most suitable for outputting different powers through pulse width adjustment. While limiting the pulse width or limiting the current, the duty cycle of the entire output of the LED light is adjusted. For example, a single 1W LED with 7 strings of 5 and a total of 35W LED lights can be discharged at night, and the late-night and early-morning periods can be performed separately. Power adjustment, such as adjusting to 15W in the middle of the night, adjusting to 25W in the early morning, and locking the current, can meet the lighting all night, and save the configuration cost of the battery board and the battery. Long-term tests have proved that the LED lamp with pulse width adjustment method generates much less heat and can prolong the service life of the LED.

In order to save power at night, some lamp factories make the interior of the LED lamp into 2-way power supply, and turn off one power supply at night to achieve half of the output power, but practice has proved that this method will only lead to half of the light source first light. fading, inconsistent brightness, or early damage to one light source.

Five: Line loss compensation

The wire loss compensation function is difficult to achieve by conventional controllers at present, because software settings are required, and automatic compensation is given according to different wire diameters and wire lengths. Line loss compensation is actually very important in low-voltage systems, because the voltage is low and the line loss is relatively large. If there is no corresponding line loss voltage compensation, the voltage of the output terminal may be much lower than the input terminal, which will cause the battery to advance. Under-voltage protection, the actual application rate of battery capacity is discounted. It is worth noting that when using a low-voltage system, in order to reduce the line loss and voltage drop, try not to use too thin cables, nor too long cables.

Six: heat dissipation

In order to reduce costs, many controllers do not consider the heat dissipation problem, so when the load current is large or the charging current is large, the heat increases, and the internal resistance of the field tube of the controller is increased, resulting in a significant decrease in the charging efficiency, and the service life of the field tube after overheating is also shortened. Greatly reduced or even burned, especially in summer, the outdoor ambient temperature is very high, so a good cooling device should be essential for the controller.

Seven: MCT charging mode

The charging mode of the conventional solar controller is to copy the three-stage charging method of the mains charger, that is, three stages of constant current, constant voltage and floating charge. Because the energy of the mains grid is infinite, if the constant current charging is not performed, it will directly cause the battery to explode and be damaged. However, the power of the solar street light system is limited, so it is not necessary to continue to use the constant current charging method of the mains controller. Scientifically, if the current generated by the panel is greater than the current limited by the first stage of the controller, it will cause a drop in charging efficiency. The MCT charging method is to track the maximum current of the battery board without waste. By detecting the voltage of the battery and calculating the temperature compensation value, when the voltage of the battery is close to the peak value, the pulsed trickle charging method is adopted, which can make the battery fully charged. Overcharging of the battery is also prevented.