Many hazards are associated with substation battery maintenance, especially when the DC system cannot be taken out of service without interrupting critical operations. The Black Start Mobile DC Trailer and the BlackStart Power Dock provide a seamless and reliable transfer of substation DC power to those critical DC loads by allowing technicians to safely and confidently make and break parallel between the DC systems by eliminating arcing at point of connection and reducing exposure, keeping technicians away from batteries during the process. The Black Start Battery Rack with built-in spill containment, provides a rugged fail-safe system that withstands road travel, protecting the batteries. H2 sensing and ventilation ensures a safe atmosphere while providing alarming, indication and safety shutdown features. From a safety and reliability standpoint this trailer is an indispensable piece of equipment.