BATTERY MONITORING SYSTEM FOR LEAD-ACID BATTERY BASED ON MOLALITY OF ACID

摘要

A battery monitoring system (12) for monitoring the capacity or capacity loss of a lead- acid vehicle battery (10) comprising an electrolyte of acid and water, the battery having a charging phase during which a charge level of the battery is increased, a discharging phase during which the charge level of the battery is decreased and a measurement phase during which measurements are taken to determine the capacity. The battery monitoring system (12) comprises; a measurement device for measuring, during the measurement phase, at least first and second open circuit voltage (OCV) measurements from the battery (10) when no load is being driven by the battery, the OCV measurements being taken at first and second charge levels, respectively, and a processor configured to predict a minimum OCV corresponding to a minimum charge level of the battery (10) on the basis of the first and second OCV measurements; and to determine the capacity or capacity loss of the battery (10) on the basis of the first and second OCV measurements and the minimum OCV.