Methodology for calculating the lifetime of storage batteries in autonomous photovoltaic systems

Dmitriy N. Karamov, Ildar R. Muftahov, Vasiliy V. Potapov , Anton A. Syromyatnikov, Ilya N. Shushpanov

Melentiev Energy Systems Institute of Siberian Branch of the Russian Academy of Science, Irkutsk National Research Technical University

This paper presents a versatile and simple methodology for calculating the lifetime of storage batteries in autonomous photovoltaic systems. A description is given of battery categorization and its importance in establishing potential configuration options. Battery operating modes are modeled using the chronological modeling method which defines the mode indicators with respect to every hour of the period under consideration. The notions of partial cycle and local minimum state of battery charge are introduced. These indicators are necessary for the correct estimate of the number of battery cycles to failure. After identifying the number of cycles to failure and the average annual number of cycles, it is possible to calculate storage battery lifetime. This methodology was used in 2015 when designing and setting up Verkhnyaya Amga, a photovoltaic system in the Republic of Yakutia. The results showed that it is best to use lead–carbon batteries with a total capacity of 144 kW·h.

autonomous photovoltaic systems, storage batteries, lifetime, partial cycle, depth of discharge