The term "fairy lights" refers to the strings of small lights commonly used as decorations for holidays and other occasions. The use of his term is most common in the United Kingdom, and the name is derived from the small, fleeting flashes of light that are said to announce the presence of fairies — mythical forest creatures that are said to inhabit a world somewhere between the material and etheric realms. Solar powered fairy lights use the energy of the sun to power the lights, so they can be strung anywhere that receives sunlight.
Solar powered fairy lights operate in much the same way as solar landscape lights. The string is connected to the terminals of a pair of rechargeable batteries, and the batteries are, in turn, connected to a small solar panel. The panel generates enough power to charge the batteries during the day, and when the sun goes down, a sunlight sensor switches the lights on automatically. The bulbs use a small amount of power, especially if they are solar powered light-emitting diode (LED) lights, so there is usually enough charge in the batteries to keep them on all night. In the morning, the sensor switches the lights off, and the solar panel begins recharging the batteries.
These lights can be white or multicolored and can be set to twinkle by replacing one of the bulbs with one that has a bi-metallic strip. For a more sophisticated twinkle pattern, it is possible to add a controller to the string to make them twinkle in unison, randomly or in a pattern. In myths, fairies are said to be unpredictable, so randomly twinkling solar powered fairy lights might be more reminiscent of the "real" thing.
One of the advantages of solar powered fairy lights is that they are virtually maintenance-free. There is no need to unplug them when they are not in use, and they consume no energy other than what the sun provides. When they begin to lose power and don't stay on all night, it's usually a sign that the panel needs cleaning or that the rechargeable batteries need to be replaced.
Solar powered fairy lights can be used to provide trouble-free garden illumination and landscape lighting. They are available as single bulbs to hang from a tree branch and can be incorporated into figurines. Placing solar powered lights strategically in a garden not only adds a whimsical touch, it also highlights garden features and provides light for safe passage around obstacles.