We’ve all been there: you sit down in the car, turn the key, and the car doesn’t start. Maybe you left the lights on, a door open, you haven’t driven much lately, or maybe it’s just time for a new battery. Whatever the circumstance, a car that won’t start because of a dead car battery is an unpleasant experience. Thankfully there is a temporary solution – you can jumpstart a battery.
Jump-starting a car battery is a fairly straightforward process but can be dangerous if done improperly. It’s also part of basic car maintenance. Keeping your vehicle healthy and well-maintained is an important safety measure.
With this handy guide you’ll learn how to jumpstart a dead battery in no time.
Ready to get started? You’ll want to be prepared before diving into jump-starting a car battery.
Before getting started you will need to acquire jumper cables. You can find jumper cables at your local automotive store or auto parts shop. In fact, there are jumper cables available for purchase with different capabilities and at various price points.
When purchasing jumper cables look for longer (20+ ft.) and thicker cables, as they will be more durable, since you won’t always be able to place the vehicle you are using as a power source close to yours.
To get your car up and running again, you’ll also need to establish a power source, either another vehicle or a portable jump battery (or jump box). If you do not have jumper cables, ask to borrow some from a neighbor or friend, and hopefully you can then use their vehicle as your power source, too.
Once you’ve obtained your jumper cables and your power source, follow these steps to get your car running again.
Unless you’re using a portable jump battery, you’re going to be using the power of another vehicle to jumpstart a battery. You will need that vehicle as close to yours as possible so that the jumper cables can reach from battery to battery. Do not get too close though, you do not want the vehicles to touch and potentially harm the paint job or dent the exterior.
Safely open the hood of each vehicle and locate the batteries. Car batteries have two large protrusions called terminals with one being positive and one negative. There's usually a plastic hood covering the battery or the battery terminals, and you’ll need to remove this hood to access the terminals. The positive terminal will be marked with a “+” or read “POS” and will connect to the positive clip of the jumper cable, which is usually red. The negative terminal is usually marked with a “-“ or read “NEG” and will connect to the negative clip of the jumper cable, which is usually black.
Clean off any gunk that may be on the batteries to ensure you have a solid connection between batteries. To clean the battery, use a very small amount of water mixed with some baking soda and apply it to the debris around the terminals. Then, using a toothbrush, scrub the battery until the debris disappears.
Dry off with a towel once the debris is gone. Cleaning off the debris can help prevent shortages in the connection, as well as optimize your battery’s performance . It can also help protect your battery’s lifespan.
Make sure to turn off both vehicles to keep from harming yourself before attaching the jumper cables. Also be sure to remove the keys from both ignitions prior to attaching the cables — this also will help ensure that both vehicles are safe from circuits overloading and overheating. This is known as electrical arcing , which can also you harm.
CAUTION : Once you begin the next steps, do not touch the metal portion of the jumper cable clamps to each other. If the clamps do touch when they're hot, you could cause a short in either vehicle and create some dangerous sparks.
When you jumpstart a car, you are creating a circuit that carries the current from the the live battery over to the dead one to provide enough charge in the dead battery to restart the car. In order to do this successfully the cables should be connected in this exact order.
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Take the red (positive, +) clamp of your jumper cables and attach it to the positive terminal of the dead battery.
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Hook the red clamp of the jumper cables to the positive terminal of the working battery.
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Attach the black (NEG, -) clamp to the negative terminal of the working battery. Your jumper cables are now hot!
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Take the remaining black clamp and attach it to any unpainted and clean metal surface under the car’s hood with the dead battery to ground the connection. Make sure not to touch the two ends of the cables together while doing this.
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Once you have the jumper cables properly attached, start the engine of the working car. Allow it to run for about 1-2 minutes. Rev the engine slightly by pressing on the gas pedal lightly.
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Next, start the engine of the car with the dead battery. If the car still isn’t starting, check the connection of the jumper cables to the batteries and make sure there isn’t any gunk interrupting the connection between cable and battery. If connections are secure, you may just need to let the good car run for 5-10 minutes while hooked up to the dead car to help build a charge in the dead battery to allow you to restart it.
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When the car with the dead battery has started, let it run for around 20 minutes to allow the battery to recharge before turning the cars off again.
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Once you’ve let the battery recharge you can remove the jumper cables in the reverse order that you put them on the terminals.
Do not try to restart the car with the dead battery more than three to four times or you may cause serious electrical damage to the car. If your car still won’t start, you’ll need to contact a service station. Use our locator to find Auto Parts and Services Locations.
A good rule of thumb is to test your battery each time you have your oil changed to help avoid jumpstarting a car battery. Also, if you have a second car that you don’t drive very often, it’s still best to give it a drive at least once a month to keep the battery charged. Even between oil changes, you can request a free battery test at many automotive parts stores. And when it’s time to replace your battery, use the Synchrony Car CareTM locator to find a shop near you that accepts the Synchrony Car CareTM credit card.
Learn more and apply now for the Car CareTM credit card.