Solar Powered Garden Lights Guide
Introduction to Outdoor Solar Lighting for Home and Security Use
Jan 1, 2009
The development of high-efficiency white LEDs has made solar powered lights practical. They are now popular as easy-to-use outdoor lighting, for decorative and security use.
How Solar Lights Work
Solar cells at the top of the light charge a battery during the day. At night, the battery is used to power an LED light.
The light is entirely self-contained, not having any wires to an external electricity supply. They are often built with a long spike at the bottom of a post so that they can be easily planted anywhere in the garden.
Internal Battery Type
The weak link in solar lights is the battery. Rechargeable batteries last a few years at best. New solar lights might have faulty or weak batteries.
Ideally, solar lights should use rechargeable AA batteries so that they can be replaced when necessary. Unfortunately information on the type of battery used is not often available, especially when buying online.
If buying from a shop, permission can be obtained from the sales staff to open up a display unit to check if the battery can be replaced. Online forums can also be researched for information.
Performance
Solar lights that have enough energy to last the whole night are rare. A few hours of illumination can be expected, which can get worse as the batteries age.
Performance will also be reduced if there isn't enough light to fully charge the battery, for example in
- shady locations
- winter
- rainy weather
Danger of Theft
Easy to install also means easy to remove. Solar lights can be easily stolen simply by pulling them out of the ground. If this is a concern, they can be cemented into place just like ordinary lights.
Environmentally Friendly Lighting?
All lighting systems have some environmental impact.
- Fluorescent bulbs contain mercury, causing disposal problems
- Incandescent (tungsten filament) bulbs use more electricity
- Solar lights use rechargeable batteries, which need to be replaced every few years
Hard figures comparing the environmental costs of the different options are hard to find. In any case, all lighting methods will have significant energy and material costs in constructing the metal posts and glass housings of the lights.
Solar versus Conventional Lighting
Despite the green halo surrounding solar energy, the environmentally-conscious thing to do is to "reduce": not installing garden lights of any kind, solar or otherwise, unless necessary.
Solar lights can be a good lighting solution for remote trails and shelters (as safety or guide lights), miles away from main electrical supplies.
For a typical suburban garden, conventional wired lights are probably a better long term solution.
