Solar lighting with advanced intelligent controller

This paper reports the design and performance details of a new solar lighting project in Hong Kong. An advanced intelligent-controller was developed for this solar lighting project, which consists of 15 solar street lighting systems and 5 solar garden lighting systems at the Kadoorie Farm and Botanic Garden. The controller not only performs normal control functions, but also improves the charge/discharge characteristics between battery and photovoltaic panels. The floating and pulse charging techniques were adopted in the controlling system. Monitoring results have shown that the advanced intelligent controller operation is accurate, reliable and satisfactory. The PV lighting systems are switched-on from direct to floating charging status before approaching the battery's full capacity for reducing the battery polarizations. Voltage pulses are developed by the controller to charge the batteries for cloudy/rainy days so that the size of the battery and PV panels is smaller for reducing capital investment.