How do solar street lights do not turn on during the day when they are charged?

In the construction of new rural areas, solar street lights are favored by everyone because of their environmental protection advantages, and for solar street lights, charging solar energy during the day and lighting at night is the basic requirement for solar lighting systems. There is no additional light sensor in the circuit, and the output voltage of the photovoltaic panel shall prevail, which is also a common practice in solar energy systems. So how do solar street lights do not turn on at night when they are charged during the day?

There is a detection module in the solar controller. Generally, there are two methods:

1) Use the photoresistor to detect the intensity of sunlight; 2) Use the voltage detection module to detect the output voltage of the solar panel.

Method 1: Use a photoresistor to detect light intensity

The photoresistor is particularly sensitive to light. When the light intensity is weak, the resistance is large. As the light becomes stronger, the resistance value decreases. Therefore, this feature can be used to detect the intensity of the sun's light and output it to the solar controller as a control signal for turning on and off the street light. A photoresistor and a simple photosensitive circuit are shown in the diagram below.

A balance point can be found by sliding the rheostat. When the light is strong, the photoresistor value is small, the base of the triode is high, the triode is not conducting, and the LED is not bright; when the light is weak, the photoresistor resistance value Large, the base is low, the transistor is turned on, and the LED is lit.

However, utilizing photoresistors has certain disadvantages. Photoresistors have relatively high installation requirements and are prone to mis-control on rainy and cloudy days.

Method 2: Detect the voltage of the solar panel

Solar panels convert sunlight energy into electrical energy, the stronger the light, the higher the output voltage, the weaker the light, the lower the output light. Therefore, the output voltage of the battery board can be used as a basis to turn on the street light when the voltage is lower than a certain level, and turn off the street light when the voltage is higher than a certain level.

This method can ignore the impact of installation and is more direct.

The above method of solar street lights charging during the day and not lighting up at night will be shared with you here. In addition, solar street lights are clean and environmentally friendly, easy to install and do not need to lay electrical lines, saving a lot of manpower and material resources. The installation efficiency is also improved, and it has good social and economic benefits.