Opportunity for improving lead-acid battery management of photovoltaic-genset-battery hybrid power systems based on measured field data

Abstract

In this communication, the measured behaviour of a lead-acid battery bank within a stand-alone residential solar photovoltaic (PV)-genset-battery hybrid power system in Canada is presented and discussed. In order to capture rare field-based battery performance data, a newly commissioned lead-acid battery bank was equipped with a battery monitoring device capable of logging voltage, current, temperature and amp-hours every 30 s for the life of the battery. The measured data captures a severe loss of battery capacity due to a combination of short-term deep discharge and extended partial state of charge operation—conditions not unusual during winter season PV-genset-battery hybrid power system operation. Subsequent manual override of the system control set points to encourage gradual battery overcharge are shown to recover the lead-acid battery bank’s performance over the following three months. Limitations of the power conversion system’s battery management approach are discussed and a novel closed loop control system for improving lead-acid based PV-genset-battery hybrid system performance is rationalized and proposed for further research.