fatto!

Solar Home System

The SHS cost about US$300 each, and consist of a 40 Wp PV module, a 75 Ah deep-cycle battery with oversized electrolyte reservoir, a solid state charge controller, and two 11 W fluorescent lamps. The system is sized to allow both lights to be used for three hours every night in winter, with a two-day 'no sun' back-up period.

The SHS had to incorporate some special features to cope with the extremely low winter temperatures prevalent all over Ladakh. Night-time winter temperatures of -30°C are not unusual, and there is a risk of freezing batteries. To reduce the chance of this, the acid used in the batteries was of a relatively high specific gravity (1280 g/litre), and the battery was also placed inside a battery box with polystyrene sheets all around it to give it some thermal insulation. Furthermore, as wires tend to be affected by the low temperatures and over time turn brittle and break, a special polyethylene-sheathed cable was used that can withstand the low temperatures.