How Long Should a Car Run After Getting a Jump?

Your car’s battery produces the chemical reaction that turns the car on. Thus, without a functioning battery, a car won’t start. So, let’s talk about jump-starting a vehicle and how long you should let your car run after a jump. 

Steps to Jump-Start Your Car

Jump-starting a car means transferring current from a live battery to a dead battery by creating a circuit to charge the battery. 

Here is how to jump-start your car in a few easy steps: 

• Park the car with a functional battery near the car with a dead battery. However, make sure that the cars do not touch. 
• Turn off both cars to prevent gasoline fumes from sparking and pop the hoods. 
• Once you locate the batteries, inspect the two terminals on both cars. These two terminals are the red/positive terminal and the black/negative terminal. 
• Connect the red/positive jumper cable to the red/positive terminal of the dead battery and the black/negative jumper cable to the black/negative terminal of the dead battery. Make sure to prevent the clamps from touching each other to avoid a spark. 
• Now, connect the red/positive clamp to the red/positive terminal on the functional battery and the black/negative clamp to the black/negative terminal on the dead battery.
• Attach the other end of the black/negative jumper cable to an unpainted metal surface on the working car. This helps complete the circuit and grounds it. 
• Start the working car and let it run for a minute before trying to start the dead car. If the dead car starts, keep it connected for a few minutes before removing the jumper cables. This helps you charge the battery a little before it starts charging itself. 

Why Should You Keep a Car Running After a Jump?

After jumping a car, it’s important to keeping it running for a while. The car’s battery gets charged by an alternator connected to the engine’s crankshaft with a belt. The belts turn the magnets inside the alternator to produce a sustainable charge. After the alternator creates an electrical current, the alternator spreads it to various car components that operate on electricity. As a result, the battery starts charging. This is why the engine needs to run for the belt to turn and the alternator to charge to fire up various vehicle components. 

How Long Does It Take to Charge a Car Battery?

After jump-starting your car, it is recommended to run your vehicle for at least 30 minutes, as that’s how long it takes to charge a dead battery entirely, or at least sufficiently. 

But there’s no definite answer to how long you should keep the vehicle running because there are other factors like the condition of the battery, the amount of charge in the battery when it was jumped, and the size of the battery. 

Signs of a Dying Battery

To diagnose the issue before you are left stranded somewhere due to a dead battery, here are signs you may need a battery replacement: 

• Late or slow start: If your car is slow to start, the engine doesn’t turn over quickly, or fails to turn over completely, your battery might be weak due to a faulty alternator or starter. 
• Dim lights: Dimmer than usual headlights or flickering lights, and issues with other system components, such as radio, navigation, and side-view mirror adjustments are other signs the battery is losing power. 
• Check engine light: A clicking noise accompanying the check engine light could indicate a dying battery.
• Pungent odor: A smell of rotten eggs may indicate a battery leak because the sulfuric acid in the battery gives off a pungent smell. If leaking, the battery should be replaced immediately. Since leaks can be caused by overcharging, do not overcharge your battery when charging externally. 
• Worn out cables or connectors: The cables or connectors that link the battery to the rest of the car succumb to wear and tear causing the battery to build up corrosion, preventing the flow of electricity and the engine from starting. This is another sign of a battery leak and must be addressed immediately. 

Tips to Keep Your Battery Healthy

Fortunately, there are strategies to promote battery health and measures drivers can take to be prepared if a battery issue occurs.

Drive:

For starters, drive, drive, and drive some more. As simple as this seems, driving maintains battery health and extends its lifespan because the battery recharges when the engine is on. If you don’t drive around much, it’s best to start your vehicle and keep the engine running for at least 10-15 minutes every day to prevent the car’s battery from discharging completely. 

Find the Battery Age:

Car batteries are made to last three to six years, depending on how you maintain them. If your battery is showing signs of weakening, check the expiration date, and if it is over three years old, consider replacing it. If you have to jump-start your car frequently, check for other problems, like a faulty starter or alternator, and fix it. 

Clean the Battery:

Humidity can cause rust to develop in the battery terminals. With regular battery terminal cleaning, you can avoid a reduction in performance and keep your battery running longer. To start the process, disconnect the battery and use a wire brush along with a water and baking soda mix to scrub away the rust. After rinsing and letting it dry, reconnect the battery.

Charge Battery:

Beyond cleaning the battery, charging is another maintenance method. Charging the battery with a mobile charger combats the battery depletion that occurs when the vehicle isn’t driven. Depending on your situation, the charging cadence might vary, although some recommend doing it monthly. Charging the battery is particularly beneficial when vehicles are left undriven for weeks to months. Here it makes sense to charge before storage and again immediately after when you plan to drive it again.

Although charging the battery has its benefits, be careful to avoid overcharging which can cause leaking. 

Test the Battery:

Testing your battery can provide insight into its health before an issue occurs. Once a battery is three years old, consider testing it every six months. Although a battery test is a complimentary service at some garage and parts centers, it is something you can conduct at home with a $10 multimeter which measures volts and amps.

When testing the strength of the battery, use the multimeter to test the resting, crank cycle, and idling voltage.

• For resting voltage, it should read 12.2 to 12.6 volts (less than 12.2 volts indicates the need for replacement or charging).
• For crank cycle voltage, it should display above 10 volts (less than 10 volts demonstrates a need for charging or replacement).
• For idling voltage, the battery should maintain a steady draw at 14-14.5 volts (under 14 volts implies a weak battery or a failing alternator).

You can also use a multimeter to test the alternator. 

In addition to acquiring a multimeter, a mobile charger, jumper cables, and cleaning gear for the battery, you may consider a portable jump box. Approximately $40-$100, a portable jump box bypasses the need for a secondary vehicle when jump-starting your car. This is a handy item to keep in your vehicle should an unfortunate battery issue occur. 

Summary

Your car’s battery might need a jump-start when it’s weak or because of other problems with your vehicle. If you can’t drive the car due to a worn-out battery, replace your battery to avoid any unpleasant circumstances. And jump-start it as needed. 

Matt Yantakosol is a lifelong automotive enthusiast and former consultant focused on the consumer aspect of the industry. He has traveled to New York, Detroit, Chicago, L.A., Paris, Geneva, Frankfurt, and Tokyo Auto Shows to track and observe the newest industry innovations. In addition to JDPower.com, Matt's writing has appeared on Pcarmarket.com.

Related Resources

• VIN Lookup
• All Cars for Sale
• Sell My Car
• Compare Cars
• Car Finder Tool
• Car Ratings
• New Car Previews
• Expert Car Reviews
• Car Trade-in Values