Performance of photovoltaic supplied systems with NiCd battery storage

For small-scale photovoltaic supplied devices, NiCd rechargable batteries are commonly used for storage. The charging efficiency is a function of the state of charge, the charging current and the temperature of the battery cell. In particular, the charging efficiency becomes zero, if the charging current falls below a certain value depending on the state of charage. For a detailed analysis of these relationships a computer model of a photovoltaic system incorporating a NiCd-battery has been developed. This model has been verified with a simple experimental device. The paper gives a survey of the studies and presents first results.