A portable auxiliary power source includes a clamshell-type housing including a top section or cover and a bottom section hingedly connected together. The housing provides a watertight chamber which fully encloses all internal components. Disposed within the housing are a battery, a pair of charging cables, and a pair of charging clamps. Also disposed within the housing is a control panel which includes a work light, battery charge status indicators, a charge status button, battery monitoring circuitry, an on/off switch. Further the control panel may include a 12 volt charging port, an AC charging port, and a 12 volt DC socket. The control panel provides a storage tray for storage of the charging cables and charging clamps.