Abstract: An automatic load shed control for a spacecraft power system employs a selectable one of a plurality of charging gains to approximate a state of charge in a secondary battery system. An ampere hour meter is initialized when the battery system is known to be fully charged and the inefficiencies of the charging system are lumped into a charging gain parameter. An output of the ampere hour meter is compared with a load shed threshold to determine the time for load shedding. The charging gain can be remotely changed as required to a value which causes the output of the ampere hour meter to track the true state of charge of the battery system closely enough for system satisfactory operation of load shedding. The charging gain may be a constant or may be a variable in dependence on the state of charge of the battery system. Charge which is delivered at a rate below a predetermined threshold is ignored by the ampere hour meter.