How to Safely Jump-Start a Car

One of the worst feelings in the world is when you go to turn on your car and—click. Nothing. Your battery is dead.

Thankfully, though, a dead car battery is one of the easiest car problems to fix. With the right tools and know-how, you can jump-start the car and be on your way in just 5-10 minutes!

What You Need to Jump-Start a Car

Preparation is key when it comes to jump-starting a car. Because if you don’t have a set of jumper cables or a portable jump-starter, you’re not going anywhere anytime soon.

You should always keep a good set of jumper cables in your vehicle. If you don’t have any jumper cables, pick up a quality pair soon! Look for 4- to 8-gauge cables that are 10–20 feet long. (The lower the gauge, the more “heavy-duty” the cables.)

Read: Car Emergency Kit Checklist: 13+ Items to Keep in Your Car [Printable]

To be extra prepared, you can also keep a portable jump-starter in your car or garage. A portable jump-starter allows you to charge your car battery without another vehicle.

If you have a portable jump-starter, make sure you keep it charged. Most portable power packs are only good for a single jump before they need to recharge.

How To Use Jumper Cables

Locate your jumper cables and find another car that can serve as the “booster car.” Pull that car next to the car with the dead battery. Depending on where the dead car is parked and where the batteries are located, you could park them side-by-side or nose-to-nose.

Turn the booster car off and make sure both vehicles have the parking brake engaged.

Pop open the hoods and identify the battery terminals.

The positive terminal will have a “+” or “POS” near it. It often has a red plastic cover; take it off. The negative battery terminal will have a “–“ or “NEG” near it.

Use a clean cloth or gloves to wipe away any dirt or debris on the battery. Inspect the battery for cracks, corrosion or leaking battery acid. If you see any of these, don’t try to jump-start it; install a new battery.

Read: How to Clean Car Battery Contacts in 4 Easy Steps

Unwind your jumper cables. If you have someone who can help you, have them hold one end while you hold the other end, making sure the clamps do not touch.

From this point on, make sure the metal clamps on the jumper cables do not touch each other or any metal surfaces on the car. If the clamps touch metal when they’re hot, it can create dangerous sparks!

Attach a red (positive) clamp to the dead battery’s positive battery terminal, making sure the clamp has a good “bite” on the terminal.

Make sure that the black clamps are not touching any metal, then attach the other red (positive) clamp to the positive terminal on the booster car.

Next, connect the black (negative) clamp to the negative terminal in the booster car.

Finally, connect the other black (negative) clamp to an unpainted metal surface (bolts or brackets work well) in the engine bay of the dead car. Placing the clamp away from the battery lowers the risk of sparking and fire.

Check that the cables are not near any moving parts and then start the booster car. Wait a couple of minutes and then try to start the dead car. You may have to hold the key in the “start” position for a few extra seconds.

If the battery is really drained, it may need to charge for a while longer before the car will start. To speed up the charging, try revving the engine in the booster car.

If after 5-10 minutes of running the booster car, the dead car still won’t start, you should stop trying and get a tow to your local repair shop.

Once the jump-started car is running, let both cars idle for a couple of minutes before removing the cables.

When disconnecting the cables, go in reverse order:

• Black clamp on jump-started car
• Black clamp on booster car
• Red clamp on booster car
• Red clamp on jump-started car

Be sure to drive the jump-started car for at least 20-30 minutes to give the alternator time to charge the battery.

If your battery is old or the alternator isn’t working properly, you might have to jump-start the car again, so make sure you are somewhere safe and accessible when you turn off the car.

How to Use a Portable Jump-Starter

It’s always a good idea to use the portable jump-starter’s manual first. Although the general process is always the same, your model may have particular instructions you should follow.

Step One

Set the portable jump-starter on the ground near your vehicle, making sure that it is turned off. Pop the hood and identify the battery terminals. Clean off the battery as needed.

Step Two

Unwind the cables. Attached the red (positive) clamp first, then attach the black (negative) clamp to an unpainted metal surface.

Step Three

Turn on the jump-starter. Wait a couple of minutes and then try to start the car. If it won’t start, let it charge for a few more minutes and then try again.

Once the vehicle is running, turn off the jump-starter. Remove the black clamp and then the red clamp and safely store the jump-starter. Be sure to charge it up again when you get home!

Do I have to replace my battery?

Do you have to replace your car battery after a jump-start? Not always. It depends on whether your battery is still in good condition.

Some of the signs that it’s time to replace the battery include:

• Corrosion (white build-up) around the positive and negative connections
• Slow engine crank
• Illuminated check engine and/or battery light
• Swollen or bloated battery case
• Battery leak
• Low battery fluid level
• Age (older than five years)

Read: How Long Is a Car Battery Supposed to Last?

It’s also possible that something unrelated to the battery is causing the problem. There could be a blown fuse, faulty alternator, bad starter connection, or other electrical problems.

Roadside Assistance

Stranded with a dead battery? We’ve got you covered! If you’ve brought your vehicle to our stores for service in the last year, you qualify for our complimentary Roadside Assistance program. Use any towing or roadside assistance service and we will reimburse you up to $100!

Testing, Testing, 1, 2, 3

If the battery is old, bring it to Virginia Tire & Auto and get it tested. The voltage reading will let us know if the battery is still good or if it’s time to replace it.

If the battery is good but the car still won’t start, we can help with that too! We’ll take a look at your vehicle’s electrical system to determine what’s going on and how to fix it.

Time for a replacement? We’ll get you back on the road in no time. We’re proud to carry Interstate Batteries, America’s No. 1 replacement battery. Bonus: our technicians use a special process to install your batteries that ensures your radio, navigation and other presets stay locked in.