When starting a car, make sure the power level is or above 20%. Connect the red clamp to “+”, and the black clamp to the “-”. Then connect the battery line to the start power supply and switch to the start position. After starting the car, unplug the start power supply first, and then remove the battery clamp.Compatible with all kinds of electronic products You may not realize just how important a Power Pack Jump Start is important for your car until you have a flat battery in the middle of nowhere. It is important to make sure that you always have it in your car when you are traveling. It allows you to start your engine without flagging down another motorist for help or calling a mechanic.