How to Jump Start a Car (with diagram)

If you cannot start your gas/diesel powered car and you hear it trying to start, then you probably have a dead battery.

Luckily, you can solve this temporarily with a simple jump start.

Jump starting your car will allow you to get home, to an auto parts store or to a mechanic, where you can get the bad battery replaced.

Here are the supplies you need and how to do it.

You'll learn 2 different jump starting methods in this tutorial.

Why a Jump Start Works

When your battery dies, it does not have enough electricity to start up the engine, which turns the alternator, which charges the battery.

So when you jump start a battery, you give it just enough “juice” to start the engine, which charges the battery and will keep the car running until the engine is turned off.

If your battery can still hold a charge, your alternator might be able to charge it enough for a few more starts. But it's always best to replace your battery as soon as possible.

Equipment Needed

There are 2 ways to jump start a car. Here's the equipment you'll need for each method.

If you want to be super prepared, it's best to have the equipment for both.

Skip down to the next section if you already have the equipment and just want to learn how to use it.

Jumper Cables and a Car with a Charged Battery

The tried and true method is to use good ol' jumper cables. You can get them on Amazon or at any auto parts store.

See my recommended jumper cables here.

Once you have jumper cables, you'll need to have another running car. This usually means that you'll have to ask someone for some help.

Make sure the other car is a gas/diesel powered car too.

Jump Start Battery Pack

A faster way to jump start a car is to carry a portable battery.

Many of these batteries are very compact and can be kept in your glove compartment or center console.

The biggest risk is that you'll forget to charge the battery and it will not be available when you need it.

So if you go this route, setup a reminder on your phone to check the charge periodically.

You can find my recommended battery packs here.

How to Use Jumper Cables

Diagram Instructions

Connect the jumper cables to the batteries in the following order.

Disconnect the cables in reverse order.

Detailed Instructions

Find someone who is willing to help you jump start your car with their car.
Bring the car with the charged battery as close to the car with the dead battery as possible. Check to see that the cable will be able to connect the 2 batteries. Turn both cars off.
Connect the red cable to the positive (+) terminal of the charged battery. The terminals of the battery are color coded red/black or have the +/- symbols on them.
Connect the red cable to the positive terminal of the dead battery.
Connect the black cable to the negative (-) terminal of the charged battery. Be sure that the ends of the cables on the dead battery side don't touch. They will spark and could cause damage to the charged battery.
Attach the other end of the black cable (at the dead battery) to any unpainted part of the car's frame.
Start up the car with the charged battery.
Start up the car with the dead battery. The car should now start up.
Once the car with the dead battery starts up, disconnect the cables in reverse order:
1. Black cable attached to car frame at the dead battery, make sure it doesn't touch the red cable.
2. Black cable attached to the negative terminal of the charged battery.
3. Red cable attached to the positive terminal of the dead battery.
4. Red cable attached the the positive terminal of the charged battery.
Leave the car with the dead battery running. Do not shut it off until you get to your destination because it's likely that you'll need another jump to get it started again.

That's it! You now know how to jump a car battery.

How to Use a Jumper Battery Pack

Using a jumper battery is easy.

Since there can be slightly different instructions for every battery, be sure to read the instructions before using it.

But for most batteries, here are the instructions:

Connect the red cable from the battery pack to the positive (+) terminal on your dead battery
Connect the black cable from the battery pack to the negative (-) terminal on your dead battery
Turn the battery pack on
Start up your car using the key or push button starter
Once it starts, turn off the battery pack, then disconnect the cables, leave the car running

That's it!

When a Jump Start Won't Work

There are a few situations where a jump start won't work:

The dead battery cannot hold any charge, or is damaged
The alternator is damaged (because it won't charge the battery while the engine is running)
The starter is damaged (because it won't be able to send electricity from the battery to the spark plugs and start the engine)
The jumper battery pack is not charged or is damaged
The jumper cables have a bad connection

But these issues are rare.

A jump start will usually work and allow you to get home or to a mechanic.

However, if you have trouble jump starting your car battery, it's probably due to one of the reasons above.

Final Thoughts

Knowing this simple process will come in handy if your battery dies.

You can use your knowledge to help others who are stranded, even if you don't own a car.

Note: This process won't work with battery powered cars, only gas/diesel vehicles.

But as long as there are still gas/diesel powered cars on the road, this will always be the best way to temporarily solve the problem of a dead battery.