Field Experiences with Stationary Lead-Acid Batteries in Photovoltaic Power Plants

Important for failurefree and economic service is the suitability of the batteries to the special demands of photovoltaic power plants with regard to their capacity, discharge voltage, chargebility, cycle stability, low self discharge rates and little or no maintenance. A special method of power calculation for the estimation of the suitable battery type and capacity based on experience is recommended. Especially in pilot plants there is a need to measure the state of charge of the batteries and to calculate by a microprocessor datas either for power or load management. A special system "logistronic" is desribed. Design descriptions are given on systems installed in containers as well as information on photovoltaic power plants sponsered by the European Cummunities, which have been installed or will be in operation shortly. (Power between 30 and 300 W) Field experiences resulted in a complete system consisting of the following components: • bloc batteries with a special lead selenium alloy, maintenancefree operation 3 years or more, • recombination-catalysts increasing maintenancefree operation up to 15 years, • a control system "logistronic", and • pre-mounted batteries in special containers