A power monitoring and control apparatus (102, 109; 502, 503,509) for use in charging battery-mounted equipment from a power system through a battery charger, comprising a comparator adapted to: compare a current control calculation value indicative of a current value available for charging the battery-mounted equipment from the power system and a charging request value indicative of a current value requested to the battery charger from the battery-mounted equipment; and select the smaller one among the current control calculation value and the charging request value as a current control value indicative of a charging current to the battery-mounted equipment; wherein the power monitoring and control apparatus further comprises a calculation engine for calculating the current value available for charging the battery-mounted equipment from the power system based on: a secondary-side voltage of a transformer of the power system to which the battery charger is connected; upper and lower limits of the secondary-side voltage; and a connection state of the battery-mounted equipment; characterized in that the calculation engine is adapted to calculate the current value available for charging the battery-mounted equipment from the power system further based on charging forecast information of the battery-mounted equipment, the charging forecast information including at least information on a voltage and a current from charge start to charge end and a relationship with an SOC, state-of-charge, curve output from a battery controller in the battery charger, a maximum battery rating and a maximum charging speed. compare a current control calculation value indicative of a current value available for charging the battery-mounted equipment from the power system and a charging request value indicative of a current value requested to the battery charger from the battery-mounted equipment; and select the smaller one among the current control calculation value and the charging request value as a current control value indicative of a charging current to the battery-mounted equipment; wherein the power monitoring and control apparatus further comprises a calculation engine for calculating the current value available for charging the battery-mounted equipment from the power system based on: a secondary-side voltage of a transformer of the power system to which the battery charger is connected; upper and lower limits of the secondary-side voltage; and a connection state of the battery-mounted equipment; a secondary-side voltage of a transformer of the power system to which the battery charger is connected; upper and lower limits of the secondary-side voltage; and a connection state of the battery-mounted equipment; characterized in that the calculation engine is adapted to calculate the current value available for charging the battery-mounted equipment from the power system further based on charging forecast information of the battery-mounted equipment, the charging forecast information including at least information on a voltage and a current from charge start to charge end and a relationship with an SOC, state-of-charge, curve output from a battery controller in the battery charger, a maximum battery rating and a maximum charging speed.