When jumping a car battery, the red (positive) cable should be connected first, followed by the black (negative) cable. Here’s the detailed explanation in English:
Why Connect the Positive Cable First?
Prevent Short Circuits:
The car’s chassis is connected to the negative terminal of the battery (grounding).
If you connect the negative cable first and accidentally touch the positive clamp to any metal surface (like the car’s frame), it could create a spark or short circuit.
Connecting the positive cable first minimizes this risk.
Reduce the Risk of Sparks Near the Battery:
Batteries emit hydrogen gas, which is flammable.
Connecting the negative cable last (away from the battery) reduces the chance of sparks igniting the gas.
Step-by-Step Guide to Jumping a Car Battery
1. Safety Precautions
Turn off both vehicles (the dead battery car and the donor car).
Wear gloves and safety goggles to protect against sparks or battery acid.
Ensure the jumper cables are in good condition (no frayed wires or exposed insulation).
Keep the cables away from moving engine parts (like fan belts).
2. Connect the Positive (Red) Cable First
Attach to the dead battery:
Attach to the donor battery:
Why? This establishes a safe electrical path before completing the circuit.
3. Connect the Negative (Black) Cable Next
Attach to the donor battery:
Attach to the dead car’s ground point (safer alternative):
Instead of connecting the other black clamp directly to the dead battery’s negative terminal, attach it to a clean, unpainted metal surface on the dead car’s chassis (like a bolt or bracket).
Why? This reduces the risk of sparks near the battery, where hydrogen gas may be present.
If you must connect to the negative terminal:
4. Start the Vehicles
Start the donor car’s engine and let it run for a few minutes.
Try starting the dead car. If it doesn’t start, wait a few more minutes and try again.
Once the dead car starts, keep both engines running.
5. Disconnect the Cables in Reverse Order
Remove the negative (black) cable first (from the dead car’s ground point or negative terminal, then from the donor car’s negative terminal).
Remove the positive (red) cable next (from the donor car’s positive terminal, then from the dead car’s positive terminal).
Why? Disconnecting the negative cable first breaks the circuit safely.
Key Tips to Remember
Never let the positive and negative clamps touch each other—this can cause a dangerous spark.
Avoid smoking or open flames near the battery.
Inspect the battery for damage (cracks, leaks) before jumping.
If the battery is frozen or damaged, do not attempt to jump-start it.
After jumping, drive the car for at least 15-30 minutes to recharge the battery.
