How does a solar street light work

Photovoltaic effect was discovered in 1839 by French physicist, Alexandre Edmond Becquerel and the operation of solar street lights is based on this principle. Photovoltaic effect elucidates how energy received from sunlight is converted into usable electrical energy.

A solar street light unit comprises of solar panel, charge controller, battery and light source. Solar panels are made up of many solar cells that absorb solar energy and convert it into direct electrical current. Solar cells are built from a semiconductor material called crystalline silicone that can produce negatively-charged electrons and positively-charged spaces. The photons released from the sunlight push these electrons into the positive spaces in the solar cells. This forms an electrical circuit and when electrons flow through this circuit, electricity is generated. Solar panels are connected to solar batteries where this electricity is stored up via the charge controller. At dusk, solar cells stop the conversion process when there is not enough sunlight to absorb, photoreceptors on the solar lamp sense it and draw the current from the battery to illuminate the light source automatically. Again, the photoreceptors sense the sunlight at daybreak and shuts off the LED automatically. The current generated by the panel depends mainly on the efficiency of the panel, size of the solar cells and the amount of sunlight received.