Abstract: An alternating current generator for motor vehicles having an extremely small power loss and which can be simply cooled includes a power converter having at least either high side semiconductor power elements or low side semiconductor elements. The high side power elements connect an output terminal of the armature coil to a high potential terminal of the battery; the low side semiconductor power elements connect an output terminal of the armature coil to a low potential terminal of the battery. The power converter converts the alternating current generated voltage of the armature coil into a direct current voltage to supply electricity to the battery. An exciting current controller includes a switching transistor for controlling an exciting current to a field coil. The semiconductor power elements in the power converter and/or the switching transistor in the exciting current controller are/is formed of SiC material, which is a compound of Si and C, having a resistivity smaller than that of pure Si.

Abstract: A battery condition detecting apparatus includes a current detecting apparatus, a voltage detector and a current accumulator of a battery. The battery condition detecting apparatus detects a first battery capacity when an engine is started based on the battery voltage and battery current when the starter is started; determines an initial capacity of the battery based on the first battery capacity; adds to this initial capacity, a battery current accumulated value which has been accumulated by the battery current accumulator after determining the first battery capacity, whereby a second battery capacity is detected after the engine has been started; and further comparing the presently detected first battery capacity with the second battery capacity just before this first battery capacity is detected, thereby setting the smaller capacity as the initial value.

Abstract: A battery condition detecting apparatus includes a current detecting apparatus, a voltage detector and a current accumulator of a battery. The battery condition detecting apparatus detects a first battery capacity when an engine is started based on the battery voltage and battery current when the starter is started; determines an initial capacity of the battery based on the first battery capacity; adds to this initial capacity, a battery current accumulated value which has been accumulated by the battery current accumulator after determining the first battery capacity, whereby a second battery capacity is detected after the engine has been started; and further comparing the presently detected first battery capacity with the second battery capacity just before this first battery capacity is detected, thereby setting the smaller capacity as the initial value.