Can You Jumpstart A Car With 9V Battery? (Explained!)

A car battery is the one that operates and gives power to your vehicle, but a car battery can be so dead that it would require you to jumpstart your car. Let us learn if you can use a 9v battery to jumpstart your car. Keep reading to learn more.

So can you jumpstart a car with a 9v battery? The answer is no; you cannot. The voltage and the current are way too low to be able to jumpstart a car.

If the car battery is dead, you can jumpstart your car. This means that you can use jumper cables and connect them to a car that has a good and charged battery so that you can start your engine. You can do this by putting the two cars side by side. 

Turn the engines off for both cars. Pop the hood of both the cars so that you can have access to the batteries. You then need to attach the red cables to the positive terminals of each of the batteries of the two cars. 

Start with the car with a dead battery. The terminals will be marked with a plus sign, or they can be in the color red. The next thing you will have to do is attach the black cable into the car’s negative terminal with a good battery. 

You can spot the negative terminal because it is usually marked with a negative sign or in color black. You then have to attach the other black cable into the engine block of your car that has the dead battery. Attach it as far away as you can from the battery. 

If you have put the cables in place, you can now start the car’s engine with a good and charged battery. Wait for about one minute or two minutes. After that, start the engine of the car that has the dead battery. 

Allow the engines of both cars to run, and then remove the cables in the reverse order that you have them attached. It is still essential, though, to follow your owner’s manual. 

That is how you jumpstart a car. But now, we will focus if your dead car can be jump started with a 9v battery.

Can You Jumpstart A Car With 9V Battery

Are 9 Volts Enough To Jumpstart A Car?

No, the voltage is too low to jumpstart a car. You also cannot attach the big heavy jumper cables to a 9v battery. Even a 12v car battery cannot jumpstart and supply enough current to ordinary jumper cables. 

If you jumpstart a car with a dead battery, the process will significantly depend on the source. In this matter, you will depend on the car’s battery and if the battery will take enough charge to run the starter. You must have a source with at least 13.8v to get some charge into your dead battery with this. 

So for an a9v battery, it will not be enough. If you have at least 13.8v, you might charge your dead battery. The 9v battery is also too small. 

It does not have the capacity. Keep in mind that jumpstarting your car will only work if your car battery is just dead enough that it cannot start on its own without some help. 

If your car battery is really damaged and will not hold a charge anymore, then a jumpstart will not do any good. You have to take your car and replace the car battery.

Can You Charge The Car Battery With 9V?

No, you can’t charge a car battery with a 9v battery. You cannot use a 9-volt charge because it is not capable of supplying enough voltage. Some talk about trying a voltage doubling circuit, but it was not possible and practical. 

Using a 9v battery is not enough to power up a car battery. The voltage will be way too low. With that, the dead car battery might not even feel a thing. 

No charge will ever go with the dead car battery, and it will not make a difference. A dead car battery must require a higher volt to have the jolt and the proper supply of current. 

If you charge your car battery, you will have to require a higher volt to charge your car battery. Do not use a low voltage battery because it will not make any difference.

9V battery and a car

What If You Use More 9V Batteries?

If you plug two 9v batteries together, you will create an 18 volt supply and a short circuit. This can be possible, but it has significant risks. If you will try this, do it outdoors and make sure that it is on a non-combustible surface. 

There will be an internal resistance from the batteries, and they will limit the current. You can create a boiling situation, and the batteries can also leak. This means you can create a fire emergency. 

So it is essential to think ahead of time if you will use more 9v batteries and connect them. Though the thought and the idea can be possible, there are things to consider. The way you connect them can also determine the result. 

It is essential to know how you will hook them up. If you connect them in series, the result will be a times two voltage. That means you will have 18 volts at the same time with just a single battery. 

If you connect them in parallel, you will get 9 volts and two times the single battery’s current. If you snap the batteries together, that is when you will create a short circuit. 

The result will be two very hot batteries. And if the batteries are high current batteries like a lithium-ion, you might cause a fire, and the batteries can even explode.


In summary, a car battery can be so dead that it will have to be jump started with a good car battery. Jumpstarting can be done on your own. However, using a 9v battery will not jumpstart a car. 

The voltage and the current are way too low. You will need a battery with a higher voltage and current to charge your dead car battery.



Image credits – Canva

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My name is Hank, and I've been in the automotive industry for 27 years. I've been working in my own auto repair shop for the last 13 years, and now I want to help you here, on my blog. Let me know if you have any questions. Read more