Smart Solar-Powered LED Outdoor Lighting System Based on the Energy Storage Level in Batteries

A novel smart solar-powered light emitting diode (LED) outdoor lighting system is designed, built, and tested. A newly designed controller, that continuously monitors the energy status in the battery and, accordingly, controls the level of illumination of the LED light to satisfy the lighting requirements and/or to keep the light "on" the longest time possible, has been developed. The use of such a reliable solar energy-driven lighting system, with maximum time when the light is "on", will eliminate the sudden-death of light problem present in conventional photovoltaic (PV) outdoor lights and, therefore, will enhance the natural surveillance and feeling of safety in sustainable buildings and cities. Furthermore, the new smart control eliminates the overdischarge of the system battery and, thus, ensures a longer lifetime of the system battery. Experimental measurements on a system using a 30WLED light showed that the operating hours of the new system reached 29.16 h (1750 min), while the operating hours for a similar conventional system were 20.86 h (1252 min). Thus, the new lighting system was demonstrated, securing more than 40% of operating hours than the conventional systems.