Car batteries don't die often, but it's important to know the safe way to jump-start a car when they do. It takes concentration and some familiarity with the anatomy of a car battery, but it can be done in several steps and by paying close attention to safety precautions.
Inspect the battery closely. If there are any signs of leakage or corroding, do not attempt to jump the battery.
Park the cars facing each other, but avoid letting their bumpers touch. Place them in park.
Turn off the engine in the car that with the charged battery. Ensure that the accessories, lights and blinkers are turned off in both vehicles. Make sure that the voltage of both cars' batteries is the same.
Examine your jumper cables to ensure there is no corrosion or exposed wiring. Note that the red cable is the positive (+) cable and the black cable is negative (-).
Wear safety goggles and gloves to avoid potential injury.
Begin with the red, positive cable. Attach it to the positive terminal of the battery of the dead vehicle.
Attach the other end of the positive, red cable to the positive terminal of the charged battery.
Secure the black, negative cable onto the negative terminal of the charged battery.
Complete the circuit by grounding the final negative cable. Attach it to a metal, non-painted, solid area of the engine. Do not connect it to the negative terminal on the dead battery because this can cause an explosion.
Start the engine of the charged battery's car. Allow it to idle for five to seven minutes. Turn off the car's engine.
Remove the cables in the reverse order that they were placed, taking extreme caution to not allow the cables to touch. Begin with the grounded cable, then the negative cable on the charged car, the positive cable on the charged car and, finally, the positive cable on the car that needed to be jumped.
Start the car whose battery has just been charged. If it still doesn't start, repeat the process until it does. If this still doesn't work, bring your vehicle in to be serviced.
