Attach the red jumper cables first. Start by clamping one red cable to the positive side of the battery that won't start. Then attach the other red clamp to the positive side of the working battery. Next, clamp one black cable to the negative side of the working battery.
Disconnect the Cables:
Carefully disconnect the cables in the order reverse from their placement in the vehicles. Disconnect the negative cable from your car, then the negative cable from the other car, then the positive cable from your car, and, finally, the positive cable from the other car.
When disconnecting the cables from the old battery, disconnect the negative first, then the positive. Connect the new battery in the reverse order, positive then negative.” When you are replacing your car battery, It isn't always easy to remember the order in which to disconnect and reconnect the terminals.
Caution: Don't attach the negative cable to the negative terminal of the weak battery when jumping a car battery! This common mistake could ignite hydrogen gas directly over the battery. Battery explosions can cause serious injury.
Connection directly to the negative terminal of the broken down vehicle is not recommended, as this can cause sparking, which can damage the battery. In the case of old lead-acid batteries, there may even be an escape of battery acid, which could endanger people in the vicinity.
Connecting the negative terminal first can create a short circuit, potentially damaging the battery, and electrical system, or even causing injury. By connecting the positive terminal first and then the negative, you can minimize the risk of any accidents or damage, ensuring a safe and successful installation.
When installing the battery in the vehicle, the red cable must first be connected to the positive terminal. Then, the black negative cable is connected to the negative terminal.
Then, attach the jumper cables to the appropriate places. The positive (red) cable should be attached to the positive terminals on each battery. The negative (black) cable should have one end attached to the negative terminal of the dead battery, and one end grounded.
Technically, nothing will happen if you disconnect the positive terminal of your car battery first. However, if you short it out, a lot will happen. Depending on what you short the battery with, you might see sparks, be burned by conductive material, or even experience a battery explosion.
Attach the red jumper cables first. Start by clamping one red cable to the positive side of the battery that won't start. Then attach the other red clamp to the positive side of the working battery. Next, clamp one black cable to the negative side of the working battery.
If the battery is completely dead, it won't have enough power to turn over the engine, even with a jump start. In this case, you'll need to replace the battery to get your car running again. Another reason why a car battery won't jump is because there is a problem with the charging system.
After your car is running, carefully remove the jumper cables in the reverse order you hooked them up. Do not turn your car off as it may not start again. First, remove the negative jumper cable from your engine block, then remove the negative jumper cable from the good battery.
Connect Jumper Cables Correctly
Connecting booster cables seems easy enough: red to red, black to black. Many people get away with this method, but the risks are high. Incorrect jumper cable connections can cause fires and explosions, which can lead to injury or damage to your vehicle.
To safely remove jumper cables, be sure to do so in reverse order they were attached–disconnecting positive cable from each red clip first before removing any black clips.
If the connections where these cables attach are either covered in corrosion or not tightly connected, the power flow will be restricted, keeping your car from starting, even with a jump. Tightening the cable clamps or cleaning the corrosion off with a wire brush should restore the full flow of power from your battery.
If you connect a wire between the two terminals, the electrons will flow from the negative end to the positive end as fast as they can. This will quickly wear out the battery and can also be dangerous, particularly on larger batteries.
Connect positive first, negative having less potential won't arc. The higher the voltage, the greater the chance of arcing and fusion. On a car if negative first and you are touching any metal part of car, when attaching positive there is possibility of arcing through you. Your body becomes part of the circuit.
Make sure both metal clamps are firmly in contact with the terminal. Attach the other end of the positive (red) jumper cable to the positive (red) terminal of the assisting battery. Attach the negative (black) jumper cable to the negative (black) terminal of the assisting battery.
Always connect the positive (red) battery cable first. The reason is that if you have the negative (black) cable already hooked up and when you are hooking up the positive cable your wrench may contact the vehicle frame etc that is negative and you will get sparks.
Do not disconnect the positive (+) battery cable first! A slip of the wrench here creates a direct short to ground. Think instantaneous arc welder. The negative () cable is the ground cable; it is always connected to the frame or body metal and can safely be disconnected first with no chance of causing sparks.