How to jump start a car safely: a step-by-step guide for drivers

Car battery problems can happen at the most inconvenient times, and knowing how to jump-start a car is an essential skill for every driver.

Whether you’re in a quiet parking lot or on the side of a busy road, following the correct procedure will help you get back on the road safely.

Here’s a straightforward guide to help you jump-start a car while prioritising safety and efficiency.

What you’ll need

Before you start, make sure you have a few necessary items on hand:

• Jumper cables: These should be long enough to reach from one battery to another easily.
• Another vehicle with a charged battery: Preferably a similar-sized car, as using a much larger vehicle could impact the process.

Alternatively, if you have a portable jump starter, you can use it in place of a second car, which adds convenience when you’re stranded alone.

Step 1: position the vehicles correctly

The positioning of the vehicles is critical.

Place the working vehicle close to the car with the dead battery, allowing enough room for the jumper cables to connect both batteries comfortably. Align them so that the batteries are near each other without touching.

Keep the engines off and engage the parking brakes on both vehicles to prevent any unintended movement, especially if you’re on an incline.

Step 2: identify and connect the jumper cables

Identifying the positive and negative terminals on both batteries is vital. The positive terminal will be marked with a ‘+’ symbol, and the negative terminal with a ‘-’. This step should be done carefully to prevent any electrical mishaps.

1. Connect the red clamp to the positive terminal of the dead battery.
2. Attach the other red clamp to the positive terminal of the charged battery.
3. Connect the black clamp to the negative terminal of the charged battery.
4. Attach the other black clamp to an unpainted metal surface on the dead car’s engine block, rather than the battery’s negative terminal. This reduces the risk of sparking and is generally considered safer.

Using a grounded surface instead of the negative terminal on the dead battery lowers the risk of explosive gases igniting, a crucial safety aspect often overlooked.

Step 3: start the working vehicle

Once all clamps are connected securely, start the vehicle with the working battery. Allow it to idle for a few minutes, as this transfers some charge to the dead battery, creating a base for ignition.

Some recommend revving the engine slightly to boost power flow, but do this only in short bursts if necessary. Let the live car run for at least five minutes before attempting to start the other vehicle.

Step 4: start the dead vehicle

Now, attempt to start the car with the flat battery. If the vehicle does not start immediately, wait another few minutes and try again. Avoid excessive cranking, as it may drain both batteries.

If the engine starts, keep it running. Let it idle for a while to allow the alternator to charge the battery. If it doesn’t start after a few attempts, the issue might lie elsewhere, such as with a faulty alternator or a severely depleted battery that may require professional assistance.

Step 5: disconnect the jumper cables in reverse order

The disconnection process should be done carefully, as improper disconnection can lead to a short circuit.

1. Remove the black clamp from the engine block or grounded surface on the dead vehicle.
2. Remove the black clamp from the working car’s negative terminal.
3. Remove the red clamp from the positive terminal of the working car.
4. Lastly, remove the red clamp from the dead car’s battery.

Post jump-start: let the battery charge

After the dead vehicle is up and running, drive it for about 20 to 30 minutes or keep it idling to help the battery recharge. If the car stalls soon after, it may indicate a deeper issue with the battery or charging system, necessitating a check-up at an automotive service centre.