Portable ground power unit

A method and apparatus for providing portable ground power for aircraft. A ground power unit includes a lithium ion cell battery assembly and a standard three-pin aircraft ground power connector integrated into a single unit and packaged inside a ruggedized plastic housing with a carry handle, thereby eliminating the heavy and bulky power cables between the battery and connector. A battery management unit sets charge/discharge limits and provides monitoring of state of charge, health, and function. A charging connector and charging circuitry with user-selectable regulated charging limits allows simultaneous charging and discharging operations and connection into aircraft auxiliary circuits. A ganging station is provided to electrically combine the outputs of several ground power units in parallel for starting larger aircraft.