A sun jar is a jar which contains a solar-powered light emitting diode (LED). During the day, a small solar cell inside the jar charges a battery, and at night, the battery powers the LED, causing the jar to light up. This green gadget can be found in stores which carry various environmentally friendly lighting options, including science stores, and people can also make their own sun jars. Putting a sun jar together does not require very many skills.
The most basic sun jar design is simply a frosted glass glass jar. The LED inside may be colored to create colored light, or the frosting on the jar can be tinted for the same effect. Frosting helps to diffuse the light from the sun jar, making it less harsh, and it also hides the innards of the jar, which are not very visually interesting, during the day. The shape of the jar is not critically important and people may have jars of different sizes and shapes for more visual interest.
In some designs, the sun jar is completely sealed, which means that it can safely be used in damp environments. In these designs the top of the jar is left clear to allow the solar cell to charge during the day. Other designs have lids which must be swung open to expose the solar cell during the day and then swung shut at night for the jar to operate. In either case, the sun jar needs to be in direct sunlight during the day to charge.
Sun jars typically have light sensors so that the jar only illuminates in the dark. The sun jar can provide a night light, or multiple jars can be used for mood and atmospheric lighting. In the garden, sun jars can provide a reliable source of night time lighting which will not require maintenance. Campers may find sun jars too bulky to pack out with them, but for small and short trips sun jars can be handy for night lighting.
One popular do it yourself sun jar assembly technique involves taking apart solar powered garden lights and putting their innards into frosted jars. Sometimes buying and dismantling solar lamps is actually cheaper than purchasing the individual components from an electronics store or store which stocks solar supplies. People may want to price out their options to see whether a commercially produced sun jar or homemade version is more affordable.