System overview
Solar panel produces electricity during the day and stores it into a battery. Controller that has a inbuilt timer times the switching of the lamps. The lamps used in solar street lighting applications are of high efficiency types.
Functions of different components
Solar panel: Converts sun light into electric current. Rated in terms of peak watts produced. Apex stocks panels from 10Wp to 185Wp (70WHr to 1,295WHr @ 7 Hr Irradiance). For higher requirement, multiple panels are used which are connected in combination of parallel and series connections.
Solar charge controller: Regulates charging and discharging of the batteries to optimize the ‘retained charge’ of the batteries and maximize the life of the batteries. Apex stocks controllers from 3Amps to 140 Amps (PV current or Load current). Parallel connections of controllers for higher capacities is possible by using current sensors in the loop of master-slave combinations. For SHS system with 1 panel, a controller of 12 Amps is sufficient.
Batteries: Reservoirs of charge current that is being produced by solar panels, batteries are connected in combination of series or parallel to match the system voltage. Apex stocks batteries from 7Amps to 415Amps in different voltages.
Bulbs with ballast: Usually a high efficiency SOX bulb with ballast is used for this application. SOX gives out monochromatic pale yellow light. Human eyes are most sensitive to this wavelength. Sox also has high Lux per watt meaning it gives out higher light at low wattage. .
Reliability: Except for the bulb, all the components are very reliable. The bulb has a life of 1 year or less and therefore needs replacement more often then other components in the system.
Viability: With 80Wp panel, street light with 35W SOX lamp (225 Watt metal halide bulb output) can work for 8 hours. SOX with 55W and 75W outputs are also available.
*Components are of energy saver types. Apex has a ready stock of most of these components.
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