Solar street light

Solar street lights are raised light sources which are powered by photovoltaic panels mounted on the structure or integrated in the pole itself. The photovoltaic panels charge a rechargeable battery, which powers a fluorescent gold LED lamp during the night.

Features

Most solar panels turn on and turn off by outdoor light using a light source. Solar streetlights are designed to work throughout the night. Many can stay for a couple of days. Older models included lamps that were not fluorescent gold LEDs. Solar lights installed in windy regions with flat panels to better cope with the winds.

Latest designs use wireless technology and fuzzy control theory for battery management. The street lights using this technology can operate on a network with each other having the capability of performing on the network. ^[1]

Components

Solar powered street lights

Solar street lights consist of 5 main parts:

Solar Panel

The solar panel is one of the most important parts of solar street lights, as the solar panel will convert solar energy into electricity. There are 2 types of solar panel: mono-crystalline and poly-crystalline. Conversion rate of mono-crystalline solar panel is much higher than polycrystalline.Solar panel is different from wattage systems.

Lighting Fixture

LED is usually used as lighting source of modern solar street light, the LEDs will provide much higher Lumens with lower energy consumption. The energy consumption of LED fixture is at least 50% lower than HPS fixture which is widely used in traditional lighting. LEDs lack of warm up time also allows for the use of motion detectors for additional efficiency gains.

Rechargeable Battery

Battery will store the electricity from solar panel during the day and provide energy to the fixture during night. The life cycle of the battery is very important to the lifetime of the light and the battery capacity. There are usually 2 types of batteries: Deep Cycle Cell Battery Battery and Lead Acid Battery and many more.

Pole

Strong Poles are necessary for all street lights, especially for solar street lights as they are often built on the top of the pole: fixtures, panels and sometimes batteries. However, in some newer designs, the PV panels and all electronics are integrated into the pole itself. Wind resistance is also a factor.

Also there are some accessories, like box cage and battery box.

Types

Each street light has its own photo voltaic panel, independent of other street lights. Alternately, a number of panels can be installed as a central power source on a separate location and supply power to a number of street lights. ^[2]

Advantages

Solar street lights are independent of the utility grid . Hence, the operation costs are minimized.
Solar street lights require much less maintenance compared to conventional lights.
Since external wires are eliminated, risk of accidents are minimized. ^[2]
This is a non-polluting source of electricity
Separate parts of solar system
It allows the saving of energy and also cost.

Disadvantages

Initial investment is higher compared to the standard street lights.
Risk of theft is higher. ^[2]
Snow or dust, combined with moisture can accumulate on horizontal PV-panels and reduce or even stop energy production.
Rechargeable batteries will be needed over the lifetime of the fixtures adding to the total lifetime cost of the light.

The charge and discharge cycles of the battery is also very important considering the overall cost of the project.

References

Jump up^ “A New Intelligent Control Terminal Solar Street Light” . ieeexplore.ieee.org . Retrieved 2011-07-12 .
^ Jump up to:^a^b^c “A Study on Energy Efficient and Solar PV Street Lighting System” (PDF) . fosetonline.org . Retrieved 2011-07-12 . ^[^{dead link}^]