What Happens When You Jumpstart Your Car The Wrong Way: A Guide for Novice Drivers
  • Home  / 
  • Blog  / 
  • Cars
  •  /  What Happens When You Jumpstart Your Car The Wrong Way: A Guide for Novice Drivers

What Happens When You Jumpstart Your Car The Wrong Way: A Guide for Novice Drivers

Dec, 2017
What Happens When You Jumpstart Your Car The Wrong Way

You do not need to be a genius to figure out how to jumpstart a car’s battery. You simply need a car with a well-functioning battery and jumpstarting cables. Connect positive to positive and negative to negative. Unfortunately, things may not always go as planned. There are some instances wherein you might not do it the right way.

What happens when you jumpstart your car the wrong way? This is exactly what we will be exploring in the rest of this post. I will share with you some of the possible scenarios. More importantly, I will also share with you how it is possible to remedy the situation.

In a nutshell, as it is shown in the video below, the most common thing that will happen is that your car won’t start and you might need to replace the fuse:

Jumpstarting the Wrong Way: The Consequences

There are several things that can happen, but luckily, 99% of the time, it should not be a concern for your safety. There are some components that will be damaged, but it is nothing serious that can lead to your death.

Damage to Components

In the short video that has been shown above, this is the damage that became apparent after jumpstarting the car the wrong way. This is a result of incorrect polarity. The incorrect connections of the cables to the terminals of the battery can damage the electrical system, including sensors and fuses. The good news is that they can be easily replaced.

Damage to Battery

Because of the electrical surge that will be produced as a result of the incorrect connections, the batteries will be inevitably damaged. In this case, I am referring not only to the dead battery that is being jumpstarted, but also to the battery from the rescue car.

Damage to Battery

Via: https://www.youtube.com/watch?v=5wc72o07bEc

As a result, two batteries will heat up in an instant. The heat can be extreme and consequently, this can cause some of the parts of the battery to melt.

If you have lead-acid batteries, which is the most common type of car batteries, hydrogen gas will be discharged in large quantity. The casing of the battery can experience cracks because of the pressure of hydrogen gas. This will allow the hydrogen to escape and cause an explosion. This is where it gets really dangerous.

Damage to Jumper Cables

Your jumper cables can also be damaged if you do things the wrong way. The high surge of electrical current can lead to a sudden increase in temperature. In turn, this can burn the jumper cables and will make the latter unusable. The clamps and the solder can melt because of the heat.

Damage to Alternator

Because of the high electrical current, which will be too much than what the parts of your car can handle, the alternator can also be damaged. When there is an issue in the alternator, the power that runs through the system will be affected.

If there is one thing that could sum up the things mentioned above, it would be the fact that your car won’t start. Your battery cannot be brought to life if you jumpstarted it the wrong way. Worst, you might need to replace some components of your engine system.

How to Solve the Problem

From the short video that was shown earlier in the introduction part of this post, one solution is recommended – to change the fuse. The fuse can get burnt because of the extreme heat resulting from the surge of electricity. You just have to select the fuse that you have to replace. In most cases, it is the powertrain fuse.

In some cases, the fuse may not be the only one affected. In these situations, you will need to replace other parts of the car, including the alternator. If the damage is severe and if it is the battery that has been affected, you will have no choice but to replace the latter.

Jumpstarting your Car

Via: https://www.youtube.com/watch?v=kVXf7B5UoI4

Tips When Jumpstarting your Car

To prevent the problems that have been mentioned above, below are some of the most important things that you have to keep in mind:

  • Take a look at your jumper cables and make sure that they are in the right condition. They must be free from rust. If they are already worn out, even if you connect the clamp on the right terminals, it might not work out as expected.
  • Read the manual before you start. While there are general rules when jumpstarting, there are some steps that you should not miss. For instance, in the case of newer car models, you might need to attach lugs before you jumpstart.
  • See to it that the car is in park or neutral. The least that you would want is to be run over while trying to rescue your battery.
  • Be protected as you start the process of jumpstarting. Wearing goggles and gloves will lessen the possibility of suffering from an accident.
  • Before you jumpstart the battery, make sure that the liquid is not frozen.
  • Perform an inspection on both of the batteries before you start. Do not proceed if there are leaks or cracks. They can lead to an explosion.


When you jumpstart your car the wrong way, there are many things that could possibly happen. The battery, jumper cables, and electronics will be damaged, including the fuse and the sensors. There is even a risk of explosion when the problem is at its worst. Nonetheless, most of the time, the problem won’t be too severe and nothing that could cost an arm and leg.

Once you realize that you did the wrong thing, you can fix the problem on your own. In most instances, you need to check the fuse. Chances are, one of them is burnt. You can buy a replacement for this and your car will be up and running in no time.

Have you ever tried jumpstarting your car the wrong way? What happened? What did you do afterward? Share your opinions and experiences in the comment section below.