a self - contained , battery powered , cableless starting device provides high dc power levels for short durations . preferred devices have a battery , a connector terminal assembly , and a monitor / control circuit that indicates the voltage available , and limits the device output to safe voltage levels so the battery is not damaged . the connector terminal assembly preferably has 2 or more contacts , sized and dimensioned to electrically contact with selected electric starter auxiliary power input terminals . in another aspect of preferred embodiments , the coupling mechanism physically prevents the contact surface from being positioned more than 5 feet from the battery . commercial devices may advantageously include multiple batteries in a small carrying case , and have the appropriate capacity , voltage and connectors for starting a specific type of engine . for example , an especially preferred device has connectors suitable for starting a 12v or 24v powered aircraft . such devices may advantageously have an overall stick shape , such as 2 × 3 × 14 inches , and may weigh only about 3 pounds .