Lighting in public spaces such as parks, streets, squares and crossroads needs to be reliable, particularly in remote areas which may not be connected to a power grid. Solar lighting systems are stand alone units comprising of a lamp, rechargeable batteries that store the power generated during the day by the photovoltaic modules mounted on the lamp poles. Units with automatic dusk to dawn lamps and those with pre-set timers offer flexibility of usage.
Solar street lights are the most environmentally friendly and economical means of outdoor illumination. Solar photovoltaic modules have a service life of 15-20 years and long-life LED technology used in the lighting does away with the need to change light bulbs frequently. Apart from installation costs, solar street lights do not incur any recurring costs, nor do they need maintenance.
The type and power of the light bulb, the lens and the reflectors used, the height of each pole and the space between different poles – all these factors have an impact on the performance of the unit. Each unit functions independently with its own collection and control system unlike traditional grid powered lighting systems.
Low and high pressure sodium vapor lamps used in solar street lights are lit by the electricity stored in the long-life lead-acid batteries. Photovoltaic modules fixed on high quality galvanized steel poles convert sunlight into electricity during the day and charge the batteries. The systems have in-built overcharge and over-discharge cut-offs to prevent any possible damage to the batteries or the lighting.
Installation of these systems is easy as it requires no cables to be laid, nor connection to any power grid. Factory tested and assembled kits can be easily installed by private agencies. It is also an effective lighting solution for disaster areas where round-the-clock relief work is vital. Depending on the configuration of the models, once charged, the batteries may be able to provide light for 3 to 7 days. Generation of solar power to recharge the batteries continues even on cloudy or rainy days, thus ensuring reliable lighting.