Buzz
There are several reasons why a car battery might weaken and fail to start the vehicle, such as power loss due to cold weather, an old battery, or leaving the car lights on overnight. Regardless of the cause, you can use external jump-start cables to connect a dead battery to a functional one. Ensure both batteries are of the same size, then carefully clamp the cables in the correct positions. The dead battery will receive enough power to start the car engine.
Steps
Locate the Battery
Park both cars so that their batteries are close to each other. Drive the car with the good battery (the donor car) to the car with the dead battery. Typically, the battery is located under the hood, so you can park the cars side by side or facing each other. Make sure the cars do not touch!
Check the owner's manual if you're unsure where the battery is located. It will provide details about the battery's position and how to access it.
Engage the parking brake on both vehicles. The parking brake ensures the cars remain stationary while you jump-start the battery. Use the gear shift if your car has one. Shift to 'P' or 'Park' to engage the brake. Setting the car to 'N' or 'Neutral' will also prevent it from moving. For manual transmissions, shift to neutral and apply the emergency brake.
- The emergency brake might be located near the gear shift or accelerator.
Turn off the engine and remove the keys. Ensure the donor car's engine is completely off. You should hear the engine stop, and check the radio to confirm there's no power. Also, remove the keys from the car with the dead battery to prevent accidental ignition during the connection process.
- This step protects both cars' engines from voltage surges and reduces the risk of electric shock.
Check the batteries to ensure they have the same voltage. The voltage is usually printed clearly, often on a white or yellow label attached to the battery. For example, it might say '12V'. Both batteries must have the same voltage to avoid excessive current flow, which could damage the car's electrical systems.
- Batteries with the same voltage are typically the same size, but always verify the voltage on the label to avoid damage.
- If you're unsure about battery usage, avoid risks if possible. Try finding another donor battery or use a portable jump starter.
Identify the positive and negative terminals on both batteries. The wire connected to the positive terminal is usually red, while the negative terminal wire is black. If unsure, look for the '+' and '-' signs on the battery, marking the positive and negative terminals, respectively. The red cable connects to the '+' terminal, and the black cable connects to the '-' terminal.
- First, check for corrosion on the terminals. A white, green, or blue powdery substance indicates corrosion. Use a cloth or wire brush to clean the terminals.
Connecting the Cables
Keep the two clamps of the jump-start cables separate. Stretch the cables between the two cars and lay them on the ground. Position the clamps so they don’t touch each other. Any accidental contact could cause a short circuit in the car’s electrical system.
- Jump-start cables typically have varying lengths to prevent contact. If the cables are the same length, inspect them to ensure they haven’t been altered or damaged.
Attach the red clamp to the positive terminal of the dead battery. Keep the rest of the cable on the ground as you position the clamp. Double-check the '+' and '-' labels on the battery before attaching the clamp. Squeeze the clamp open and secure it firmly onto the metal terminal.
- On some cars, you may need to remove a plastic cover from the battery terminal before connecting. Twist the plastic cover counterclockwise to remove it.
- Attach only one clamp at a time. Work slowly to avoid mistakes that could damage the car.
Attach the other red clamp to the positive terminal of the donor battery. Ensure it’s securely fastened so it doesn’t come loose when the engine is activated later.
- Remember to connect red to red and positive to positive when attaching the clamps.
Attach the black clamp to the negative terminal of the donor battery. Take the black clamp and position it on the donor battery. The black clamp should be directly attached to the '-' terminal on that battery. Avoid letting it touch the '+' terminal or the red clamp.
- If you connect the clamps incorrectly, do not start the car. Carefully remove the clamps one at a time to prevent them from touching each other.
Attach the remaining black clamp to an unpainted metal surface on the car. This black clamp should not connect to the battery terminal. Instead, find a clean bolt on the engine block or an unpainted metal area on the car’s frame under the hood.
- Avoid connecting this clamp to the dead battery unless absolutely necessary, as it could cause sparks that ignite hydrogen gas emitted by the engine.
- Stay away from deep metal surfaces near fuel lines or other sensitive components.
- Keep the jump-start cables clear of moving engine parts to prevent entanglement.
Starting the Car
Start the donor car and let it run for a few minutes. Use the key to start the engine. Electrical systems like lights and the radio will activate as power flows into the dead battery. Wait at least 30 seconds to allow the battery to charge before attempting to start the other car.
- Charging time depends on the condition and age of the dead battery.
- Rev the engine to around 3,000 RPM to increase power transfer to the dead battery.
Start the dead car. Turn the key to ignite the engine. Electrical systems should activate immediately. If lights, radio, or other components don’t work, wait longer. Turn off the car, ensure the cables are properly connected, and press the donor car’s accelerator harder to increase power supply.
- If the car doesn’t start after multiple attempts, there may be another issue, such as a blown fuse.
- If the lights work but the engine doesn’t start, the battery isn’t the problem. You might hear a clicking sound, indicating a faulty starter.
Disconnect the jump-start cables in reverse order, starting with the black clamp. Remove the clamps in the exact opposite sequence of how they were connected. Begin with the negative ground cable attached to the metal surface. Remove the black clamp, then the red clamp on the donor battery, and finish with the red clamp on the newly charged battery.
- Let the engine run for a while to allow the battery to charge further, or you may need to jump-start it again.
- Handle the cables carefully, ensuring the clamps don’t touch each other until all are removed from the batteries.
Tips
- Some cars have plastic covers over the battery terminals, which must be removed before connecting the cables. You may need to pry or twist the cover to remove it.
- After jump-starting the car, drive it for at least 15 minutes to allow the battery to recharge further.
- In some vehicles, the battery is located under the rear seat or in the trunk. These cars often have a jump-start port under the hood, marked by a red cover with a '+' sign. Attach the red clamp here after removing the cover.
- Shorter jump-start cables work better as they reduce power loss over distance. Longer cables can weaken the current and increase charging time.
- Consider purchasing a portable jump starter to avoid relying on a donor car. Charge it via a USB port, then connect the cables as you would with a dead battery.
Warnings
- Avoid jump-starting a frozen battery, as it could explode. If the battery is accessible, check if the fluid inside is frozen. A bulging battery case is another sign of freezing.
- Car batteries produce hydrogen gas, which is explosive. Avoid smoking near the battery and never connect the black ground clamp to the negative terminal of the dead battery.
