January 17, 2018

How Solar Christmas Lights Work

Clark Griswald Chistmas VacationImagine how easy Christmas would have been for Clark Griswold if only there had been an alternative to the tangled, complicated, high voltage display he used to impress his neighbors. If you too have ever found yourself at odds with your Christmas lights, whether it be the expensive electric bills or the unsightly extension cords, you might like to consider solar Christmas lights as a hassle-free alternative to deck the halls.

Solar Christmas lights require no wiring installations so you can hang the strands virtually anywhere, and most turn on and off automatically. Talk about a solar solution! Just how do these solar light fixtures work? Read on to find out.

The Basics of Solar Christmas Lights

Solar Christmas lights work by converting energy from the sun into electricity that powers the illumination of the light bulbs. During the day, the sun charges a battery with the help of a solar cell. At night, this energy is released to turn on the lights.

A solar Christmas light strand functions due to three basic parts:

  1. The solar panel
  2. The battery
  3. The LED bulbs

The Solar Panel

The solar panel for solar Christmas lights contains a photovoltaic (PV) cell. A PV cell collects and converts the sun’s energy into an electrical current. When sunlight strikes the PV cell, energy is absorbed by semiconductors (such as silicon) that make up the cell. The newly absorbed energy causes a loss of electrons which flow in an electron current. This current provides the electricity needed to power the solar cell

The Battery

The solar cells of solar Christmas lights are wired to a rechargeable battery through a diode. The diode directs the electricity flow into the battery so that it does not flow back into the solar cell. A NiMH (nickel-metal hydride) battery is generally used to store the electricity during the day until it is released at night.

The LED bulbs

After the battery has charged and night has fallen, the batteries stop producing power via a photo resistor. This device signals a controller board to turn on the LED (light-emitting diode) bulbs by detecting darkness. These LED bulbs can last for roughly 100,000 hours, compared to an incandescent bulb’s 3,000 hours. After the photo resistor detects darkness, the controller board prompts the electron current from the PV cell to emit the electricity into the connected cord containing the LED bulbs, producing their glow. The same photo resistor then detects when the sun comes up, the lights stop shining, and the process repeats.