Extreme low-maintenance, lead/acid battery for photovoltaic power-supply systems in remote, tropical areas

Thousands of villages in India are still without supplies of mains electricity. Their remote locations make grid connection almost impossible, mainly because of the high costs of transmission. The best alternative is to equip these places with solar photovoltaic systems, and suitable batteries, that will meet the requirements not only for household lighting, televisions and fans, but also for linking the villages with telecommunications systems so that these communities can be brought into development projects. A comparison between nickel/cadmium and both sealed maintenance-free and flooded types of lead/acid batteries has demonstrated the economical and functional superiority of the last-mentioned of the three technologies. A design with very-low-antimony alloys and with a specific cell construction that requires no maintenance over a period of at least one year has been evaluated, especially with respect to water consumption in cycling simulations. The operating conditions relate to solar-powered telecommunications applications. The use of catalytic gas-recombination vent plugs further reduces the maintenance to such a level that the water topping-up frequency is zero during the entire life of the battery.