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Can You Jump Start a Car With a Bad Alternator?


Cars with internal combustion engines utilize alternators, but a bad alternator can lead to your vehicle not starting at all! In that case, how can you take it to the nearest auto-repair store? For that, can you jump-start a car with a bad alternator? Well, yes, you can if your starter is working fine! Jump starting can be extremely helpful, but there’s a lot of things you need to know about them. From the safety precautions to the exact process, we will tell you about all that you will need. Read on to learn more!

What is an Alternator?

Before diving into how you can jump-start a car in case of a bad alternator, let’s tell you what exactly an alternator is. An alternator basically keeps the battery charged once the car engine start’s running by converting the chemical energy from the fuel to electrical energy.

You will need to replace the alternator as soon as possible, and with a jump-start, you can at least get your car running for a while. While the alternator is not doing its job, the power to run the whole car will come from the battery. Therefore, we need to get the new working alternator installed as soon as possible since the car won’t go more than 5 to 10 miles.

So, how can you jump-start your car with a non-working alternator? Here are the steps required to do so:

Jump Start a Car With a Bad Alternator

In order to jump-start, you will need another car to use the power from its battery. Make sure that the other car has a properly working battery and alternator. The other vehicle itself should have a traditional IC engine as well.


The only main equipment that you will need, apart from your neighbor’s car, of course, would be the jumper cables. You can easily find them at any hardware store. They have clips at both ends for proper connections.

Before we begin with the process, here are a few precautions to ensure your safety as well as the vehicles’:

Before Jump Stating – Some Precations:

  • The clips at the end of the jumper cables should never touch each other once you start making the connections to avoid short-circuiting.
  • Keep the cars away from each other at some distance so that they aren’t in contact.
  • The black wire is used for the negative terminals, and the red one is used for the positive.
  • Both cars are turned off, and their keys are out of the ignition.
  • Try to jump start on a sunny day since once the car starts, the use of wipers and headlights will consume too much battery power and will drain it very quickly, making it harder for the car to move more distance.

Jump-Starting a Car With a Bad Alternator:

Now, let’s move toward how you can jump-start you can with a bad alternator:

Step 01: Connecting the Cables

Since we already know that the red wire is for the positive terminal, connect one end of the red wire’s clip to the positive terminal of the car’s battery with the bad alternator. Connect the red wire’s other clip to the positive terminal of the car with the good battery.

As for the black wire, connect its one end with the negative terminal of the good battery. We need to provide a proper ground connection for its other clip for that. To do so, connect it with any unpainted metallic part of the car’s battery we need to jump-start. It can be a nut, bolt head, or a stud.

Step 02: Starting the Engine

Put the key into the ignition and start the car with a good battery. Keep the car running for about 3 to 4 minutes so that your car’s dead battery can get some charge. It is recommended to keep the running engine at around 2000 rpm.

In case the engine is cold, you will need to keep the car running for more time than usual.


Step 03: Starting the Car With the Bad Alternator

Once some time has passed, try to start the car with the bad alternator. Make sure that all the accessories have been switched off to save power from the battery. These include the air conditioner, radio, wipers, headlights, etc.

If the car still doesn’t start, give it more time to charge. After a few minutes, try starting it again.

If you think that you may not be able to jump-start correctly and, more importantly, safely yourself, you can ask someone who has experience in the procedure. Dealing with electrical equipment can prove to be extremely hazardous if not done properly, causing damage to both you and the vehicle. Therefore, don’t take any risks when jump-starting, and if you can’t find any help, call a professional!

Jump-Starting Successful! Now What?

Now that your car has started take it straight to a mechanic. This is important because, without the functioning of an alternator, the battery won’t get charged as it’s drained. With the car moving, the battery will be drained very quickly. Once drained, you will be back at where you started and will need to jump-start all over again.

Therefore, you will have only around 5 minutes, depending on your vehicle, to take it to the auto repair shop before it dies again. Get the alternator replaced as quickly as possible and get your car driving normally again!

Jump Starter – The Alternative:

Another way to jump-start your car without using someone else’s vehicle is through jump starters. These jump starters are relatively small devices that can provide very large power in a small amount of time, perfect for your car’s dead battery.

With this portable gadget, you won’t need another vehicle even if you are in a situation where your car needs a jump start. These jump starters are quite simple, effective, and easy to use. Since each brand has its own way of doing things, jump starters from different brands may need a different procedure to work, which can be found in their user manuals. But the general method of working is stated below:

How Do Jump Starters Work?

Just like with the process defined above, you need to connect the alligator clips with the red and black wires from the jump starter with the battery terminals of the car with the bad alternator. Make sure the clips are connected with the right terminal, as shown on the clip.

Once connected, turn the jump starter on and place it somewhere without any moving mechanical parts so that the connections will not get disrupted and won’t come into contact either for safety.

You might get only one or two chances of jump-starting your car with the jump starter since the more times you use it, the lesser its peak amperage will be. And once below a required value, it won’t be of much use for jump-starting.

You should turn off any other features on the jump starter, such as any LED light, to save the jump starter power from being drained. This will allow it to produce higher peak outputs, beneficial for jump-starting.

You can find a decent jump starter at around $50. The price may go up depending on the integrated features, but you can skip the ones that you don’t need, thus saving some cost. Nonetheless, it’s better to keep one with you for times of emergency, just like with a bad alternator, as you might not have immediate access to another car with a good battery.

How to Avoid a Bad Alternator?

Jump starting may do the job for you this time, and you may be able to take your car to the mechanic to get it fixed, but this may not be good for your car in the longer run. Doing frequent jump-starting may degrade your car’s battery, decreasing its lifetime.


The alternator may fall because of a few reasons:

  • The first and foremost will obviously be the age factor. Your car’s alternator may stop working if it’s way too old and the replacement’s been due already.
  • Increased stress on the alternator when the car is kept idle for too long, with multiple accessories being used.
  • Fluids, such as engine oil can creep their way to the alternator, making it malfunction or stop working at all.

Take care of the above-mentioned reasons to ensure that your car’s alternator is working fine, or is replaced on time, so that you may not encounter a need to jump-start your car.


We hope that you have gotten the answer to your question, ‘can you jump-start a car with a bad alternator?’ With more than one way to do so, you can utilize the method that’s more feasible for you. But the bottom line is that jump-starting can cause you a lot of trouble. With it, you can drive your car to the nearest repair shop easily without having to ask for a towing service!

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