Why Don’t You Connect The Negative When Jumping A Car?

Most car drivers have experienced a dead car battery at least once. This problem will become quite troublesome when the car is driving in the middle of the road, it takes a lot of time to call for car rescue. Therefore, drivers need to equip themselves with some knowledge to be able to solve this problem by themselves safely and quickly.

Knowing how to jump your car with jumper cables can be a lifesaver in these situations, and you are usually told that you shouldn’t connect the negative when jumping a car. So the question is “Why don’t you connect the negative when jumping a car?” Find out with Car From Japan!

Why Don’t You Connect The Negative When Jumping A Car?

According to auto experts, when connecting the battery, the negative terminal of the cable must be connected to the metal part of the vehicle, not directly to the negative terminal of the dead battery. So why shouldn’t you connect the negative terminal? Connecting like this to avoid the occurrence of specific risks as follows:

when jump-starting a car always remember positive to negative
When jump-starting a car always remember positive to negative (Photo: pinterest.com)

Avoid short-circuiting, causing battery explosion: 

When jumping, the battery produces hydrogen gas, if it encounters an electric spark, it will easily cause an explosion. Therefore, if you connect directly to the negative battery terminal, it can damage the battery and electrical components of the vehicle. And we also know that battery explosions can cause serious injury…

Prevent voltage drop (reduce vol), and make your car easier to start: 

Weak batteries have a very low voltage (below 12V) compared to fine batteries. Directly attaching the negative terminal to the cathode will reduce the voltage of the good battery. If you connect the negative terminal to the side of the car, this will be avoided because of the fact that the ground wire between the battery and the side of the car (dead battery) has a certain resistance value.

Avoid lack of mass (stops the starting current): 

In fact, the negative terminal of your battery, the chassis, and the mass of the starter are connection blocks. But the battery and the side of the car are connected through the ground wire, the cross-section of the mass wire is much smaller than the side of the car, so it will prevent the starting current, making the rescued car difficult to start.

Note: the cable must be firmly clamped to the unpainted metal bar. Do not clamp on plastic, rubber, and paint.

>> Related post: The Do’s and Don’ts of Jumpstarting a Car

How To Jump Start Your Car Correctly?

Improperly connecting batteries can have extremely serious consequences. In this article, we will share with you the proper way to jump-start your car If your battery is dead. 

Step 1: Before making connections, make sure that both vehicles are off and separated, don’t touch each other when making the process. It is recommended to turn off all power-consuming devices such as DVD players, fans, lights, etc. on both vehicles to ensure that the battery is fully loaded during the process. For each of your vehicles, you need to locate the battery and where the positive (red) and negative (black) leads are. You will find that each one has two metal terminals: a negative (-) post and a positive ( +) post.

Step 2: Clamp the red end of the jumper cable to the positive terminal of the dead battery and the other end of the red cable to the functioning car-positive terminal. Be careful to avoid the clamps touching, and shorting each other.

Step 3: Attach the end of the black cable (negative) to the negative post of the live battery and connect the remaining black (-) end to a clean, unpainted metal surface under the bonnet of a dead battery vehicle. Somewhere on the engine cover is a good place.

Step 4: Start the car with a working battery and let your engine run for about 3-5 minutes before operating the car with a dead battery.  If the car still won’t start, adjust the connectors gently and make it again.

Note: The basic and extremely important principle of connecting the battery to start the car is when jump-starting a car always remember positive first to negative. And the negative pole connects to the negative one and the positive pole connects to the positive one. If wrong, the result might be an explosion.

Step 5: When your car has started, remove the jumper cables in the opposite direction from when connecting, and avoid letting the lines come into contact with each other or touch the tires and possibly the ground. 

Step 6: Leave the connected vehicle on for at least 30 minutes to give the battery enough time to recharge. During this time, remember to turn off all unnecessary devices that consume a lot of electricity, such as air conditioners, heaters, etc.

Things To Avoid When Connecting The Car Batteries

where to attach negative jump lead
Where to attach negative jump lead (Photo: pinterest.com)

– Do not attempt to start your car repeatedly, this can damage your engine.

– During the jump start process, the battery will have gas released, this gas can cause an explosion. Therefore, you should avoid using cigarettes, lighters, or other sources of ignition during the process.

– Avoid contact with battery acid, which can burn skin or clothes.

– Do not touch the vehicle during charging, you may accidentally become an electrical bridge and get an electric shock.

– Before starting the jump start process, it is necessary to dry the engine compartment with a dry cloth as well as clean the 2 terminals of the battery to ensure electrical conductivity. In addition, it is recommended to check for oil and gas leaks in case the clamps come together, which can cause fire and explosion. Make sure the battery does not swell, does not leak water, and has no signs of abnormality.

>> Read more: How To Jumpstart A Car Without Another Car?


How long should you let your car run after jumping it?

If your car does start, let it run for a few minutes to help charge the battery further. Unhook the clamps in the reverse order of how you put them on. Be sure to drive your car for about 30 minutes before stopping again so the battery can continue to charge. Otherwise, you need another jump start.

Do you hook up the positive or negative first when jumping? 

Connect the clamp on the red jumper cable to the positive terminal on your car battery, and the black one to either an unpainted piece of the metal in your engine or directly to the car chassis (the frame of your vehicle). Don’t attach the negative (black) clamp to the negative terminal of the dead battery.

Why does my battery spark when I try to jump it? 

The inductance may have crumpled when the power supply turned off and can generate a hundred-volt spark. In any phase, we get the spark when pursuing the jump-start, carefully clasping up the red jumper cable to the positive terminal of the fine battery and the other to the positive terminal of the bad battery.