Abstract: A hand truck type of device provides a portable jumper battery for motor vehicles. Battery cables which connector clips are stored in the truck as is a power cable for connection to a power outlet so that the jumper battery may be recharged by a charger carried by the hand truck. Electronic circuitry connected to the cables prevents connection to the jumper battery until the connector clips have been properly connected and the vehicle battery has sufficient charge to be sensed. The sensing actuates a periodic signal and permits the system to be turned on. A token responsive switch controls a cycle timer which allows the circuitry to complete the connection to the vehicle battery.