Patent ID: 8159189

Claim:
A state-of-health monitoring and prognosis method for a battery comprising: monitoring battery terminal voltage and current; extracting a portion of said battery terminal voltage and current corresponding to an engine cranking event; determining an intercept voltage (V 0 ) based on the extracted portion of said battery terminal voltage and current signals corresponding to an engine cranking event, wherein the intercept voltage is the battery voltage when the battery current is equal to zero; obtaining a battery open-circuit-voltage (V ocv ) before the engine cranking event; estimating a battery voltage loss (V loss ) that occurs during said engine cranking event based on subtracting the battery open-circuit-voltage (V ocv ) from the intercept voltage (V 0 ) and comparing the estimated battery voltage loss (V loss ) with a predetermined voltage loss threshold ( V loss ) to determine battery state-of-health.