Patent ID: 6696842
Filing Date: 2004-02-24
Classification: G01R

Abstract:
An electronic unit for detecting a charge condition and/or wear of a motor vehicle battery, comprising:a battery voltage detector; an internal-combustion engine rotational speed detector; and an evaluation unit receiving the battery voltage and the rotational speed of the internal-combustion engine and evaluating the battery voltage as a function of the rotational speed of the internal-combustion engine during a starting operation in order to detect the charge condition and/or wear of the motor vehicle battery; wherein a voltage threshold as a function of the rotational speed of the internal-combustion engine is defined, said evaluating unit concluding a poor charge condition and/or or a high wear of the motor vehicle battery when the battery voltage within a defined time window is below the defined voltage threshold; a quiescent voltage detector for detecting a quiescent voltage before a starting operation; wherein said evaluating unit concludes there is a poor charge condition when the battery voltage during the starting operation is below the defined voltage threshold after the quiescent voltage previously fell-below a defined quiescent voltage threshold; and wherein the evaluation unit concludes there is a high wear when the battery voltage during the starting operation is below the defined voltage threshold after the quiescent voltage previously exceeded the defined quiescent voltage threshold.