Solar powered street lights are a very good example on what can be done with solar energy. A growing number of solar street lighting projects are running in Africa, Asia and the Middle East. Some European and US cities are currently running pilot projects.
Solar powered street Lights, the future of street lighting
The concept is straightforward and we shall see more countries migrating this way. Well chosen, solar street lights are cost-effective, cost-saving and reliable.
Nuts and bolts
- Solar Panel
Its’ task is to convert the sun’s energy into electricity. Different sizes and power outputs are available. They have to be carefully chosen for the desired application. Solar panels should be able to withhold and deliver in extreme weather conditions. Some are even designed to be unbreakable (vandal-proof), while others will work well in overcast weather. A 20 year warranty on good solar panels is not unusual.
- Solar Controller
The basic circuitry on most solar powered street lights consists essentially of an automatic battery charger fed by the solar panel and a lighting controller automated for dusk to dawn operation. Automatic lighting can be triggered by a photocell or a timer. On some models a special feature dims the light at a given time, thus allowing a longer operation time
Maintenance-free batteries are generally used on solar street lights. In addition to providing energy for dusk to dawn operation, they must also be able to supply few days of backup power in case of bad weather or charger failure.
- Light Sources
The choice of lamps to use in solar powered street lights is dictated by the kind of application you’re after
- LEDs (Light Emitting Diodes) also known as SSL (solid-state lighting) have a good color rendition. A cluster of extra or ultra bright LEDs forms the lamp. LEDs consume a fraction of the energy of comparable lighting and have a very long life span. Solar LED street lights are an emerging and promising application for LED technology.
- CF (Compact Fluorescent) lamps produce a white light and are used in places where color rendering is desired.
- HID (High Intensity Discharge) lamps, mainly LPS and MH
- LPS (Low Pressure Sodium) lamps generate a monochromatic yellow-orange light and are used when color rendering is not an issue. They have a lifespan of up to 18,000 hours
- MH (Metal Halide) lamps produce a clean white light and are perfect for applications where color rendering is essential
How solar street lights work
Solar powered street lights are full of electronics…
- The solar panel converts the sun’s energy to DC electricity.
- Voltage is then regulated to a specific value by an electronic circuit to charge the battery. A solar controller protects the battery from too low and over charge.
- Now for the lighting. Contrary to LEDs, HID and CF lamps require a high voltage, particular current, and frequency to work. It is the ballast’s task to feed the lamp properly.
- We now need to control the lamp. To do so, a timer or photocell does the job of switching the light at dusk and dawn. On some advanced solar powered street lights models, intensity and color can even be adjusted.
We design and provide efficient and reliable solutions for solar street lighting systems.
If you manufacture solar street lights products and solar traffic lights, you are running pilot projects, or if you just need some advice, don’t hesitate to contact us.