LED lights powered by solar cells

In modern homes, due to limited conditions, bathrooms, dining rooms or living rooms cannot use natural light for lighting, and lights have to be turned on during the day.

Through practice, we have produced a high-brightness light-emitting diode lighting system that can be powered by solar energy during the day and by AC power at night, which solves this problem well.

When making it, the number and power of solar panels should be selected according to the power used, and the number of high-brightness LEDs used should be selected to determine whether the panels are connected in series or in parallel. The following example uses a group of 3W, 17V solar panels and 20 high-brightness LEDs to illustrate how to compose a home lighting system. The solar panels in the figure are 3W, 17V, and can be placed in a window or balcony where sunlight can be seen. Connect five high-brightness LEDs in a string and then connect them in parallel.

This is because the working voltage of the light-emitting diode is 3.2~3.5V (rated current is 20mA). In the figure, Kl is an AC switch, and the regulated power supply is a 17.5V AC regulated power supply. D1 and D2 are isolation diodes.

During the day, the solar cell supplies power to light up the LED. At night, Kl is closed to light up the LED.