Method and arrangement for determining the starting ability of the starter battery in an internal combustion engine stop-start operation

The invention relates to a method for determining the capability of a starter battery of the internal combustion engine to maintain the power supply during a stop-start operation of the engine, which drives a generator with adjustable output voltage. While the engine is running, the output voltage of the generator for a predetermined time to a lower value is set as a target value (S17 to S21). Towards the end of the predetermined period of time the battery voltage is measured (S20) is. The measured towards the end of the predetermined period of time the battery voltage is compared with a predetermined threshold (S22). The starting ability of the starter battery is found to be sufficient (S23), if the measured towards the end of the predetermined period of time the battery voltage exceeds the predetermined threshold (S22).