The life cycle operation of an energy storage system i.e. batteries in PV application, in particular in solar mini grid application, is unique. Regular cycling of the batteries in partial state of charge (PSOC) condition, especially in high operating temperature, results in rapid capacity degradation and often failure of the system. The functional characteristics and life cycle of batteries were tested at Rohini lab in Delhi for different chemistries, including 1) VRLA type AGM, 2) Ultra-capacitor technology based Advanced Lead-acid battery, and 3) Sodium ion based AHI battery, for determining their relative suitability in solar mini grid operation under the extreme operating conditions of India. This paper will present the overview of the tests conducted and the results derived from the tests.
Dr. Hasna Khan is President of PSL-USA based in California. She led the work in solar mini-grid and energy-efficienct appliances for scaling up access to electricity in the developing countries, particularly for Bangladesh, India and Nigeria.