how to use jumper cables to start a car

[DeCaroline]

The core process of using jumper cables safely involves connecting the dead battery to a live one in a specific sequence to avoid sparks and damage, then running the donor car to transfer charge. The correct connection order is crucial: positive to positive, then negative to the dead car's negative terminal last, connecting the final clamp to an unpainted metal engine block ground instead of the dead battery's negative post.

Step-by-Step Guide with a Helper Car

1. Position the Cars: Park the donor car close to the disabled car so the cables can reach, but ensure the vehicles do not touch. Turn off both engines, engage the parking brakes, and set both cars to "Park" (automatic) or neutral (manual).

2. Identify Terminals: Open both hoods and locate the batteries. Identify the positive (+) and negative (-) terminals on each. They are usually marked clearly in red for positive and black for negative. Clean any major corrosion if present.

3. Connect the Cables in THIS Order:

   • First Red Clamp: Attach to the positive (+) terminal of the dead battery.
   • Second Red Clamp: Attach to the positive (+) terminal of the good battery in the donor car.
   • First Black Clamp: Attach to the negative (-) terminal of the good battery.
   • Second Black Clamp: Attach this final clamp to an unpainted metal surface on the engine block or chassis of the car with the dead battery. This provides a ground and minimizes the risk of sparking near the battery, which can emit flammable hydrogen gas.

4. Start the Donor Car: Start the engine of the donor car and let it run for a few minutes to allow its alternator to send a charge through the cables.

5. Attempt to Start the Dead Car: Try to start the disabled car. If it starts, leave both cars connected and running for a few more minutes to further charge the weak battery.

6. Disconnect in REVERSE Order: Once the dead car is running steadily, carefully disconnect the cables in the exact reverse order you connected them:

   • Black clamp from the ground on the revived car.
   • Black clamp from the donor car's negative terminal.
   • Red clamp from the donor car's positive terminal.
   • Red clamp from the revived car's positive terminal.

Drive the revived car for at least 20-30 minutes to allow the alternator to recharge the battery sufficiently. If the battery dies again soon after, it may be old and unable to hold a charge, or there could be an issue with the car's charging system.

[McPenelope]

My dad taught me this years ago: it's all about the order. Red to dead first, then red to donor. Black to donor, then the last black to a bare metal bolt on the dead car's engine—never the dead battery's negative post. That last part prevents a dangerous spark. Start the good car, wait a minute, then try starting the dead one. Reverse the order to disconnect. Simple as that.

[DeVivienne]

I keep a set of heavy-duty cables in my trunk because my car's battery is getting old. The key thing most people mess up is where to put that final black clamp. You absolutely should not connect it to the dead battery's negative terminal. Find a shiny, unpainted metal part under the hood, like a bracket or bolt. This acts as a ground and is much safer. It’s the difference between a quick fix and a scary situation with sparks flying around the battery.