How To Charge Car Battery With Another Car?

Looking for how to charge a car battery with another car? It happens to everyone eventually—you turn the key, and nothing happens, just that dreaded “click.” While a dead battery can be a frustrating start to your day, the good news is that charging it with another car is relatively straightforward and can save you a call to the tow truck. Here’s everything you need to know to safely and effectively charge your car battery using another car’s power.

What You’ll Need

Before you begin, make sure you have the following essentials on hand:

• A second car with a fully charged battery (and in good working order).
• Jumper cables—ideally with at least 4-gauge thickness for better current flow.
• A clean, safe location for both cars (avoid jump-starting on wet or gravelly surfaces).

Step 1: Position the Cars

Start by positioning both cars so they’re close enough for the jumper cables to reach each battery. Leave at least a foot of space between them, ensuring the cars don’t touch, as this can cause an unwanted electrical connection.

• Turn both vehicles off and put them in Park (or Neutral for manual transmissions).
• Engage the parking brakes on both cars for added safety.

Step 2: Connect the Jumper Cables

Now, follow these steps closely to ensure a safe and effective jump:

1. Red to Dead Battery: Attach the red (positive) jumper cable to the positive (+) terminal on the dead battery.
2. Red to Good Battery: Connect the other end of the red cable to the positive (+) terminal on the charged battery.
3. Black to Good Battery: Now, connect the black (negative) jumper cable to the negative (-) terminal on the charged battery.
4. Black to Bare Metal: Lastly, connect the other end of the black cable to an unpainted metal surface on the car with the dead battery. This can be a bolt on the engine block or chassis. Avoid connecting directly to the dead battery’s negative terminal to reduce the risk of sparks and possible explosion from battery gases.

Step 3: Start the Working Car

Once everything is connected, start the car with the good battery and let it idle for a few minutes. This allows the working battery to send a charge to the dead battery. If your cables are in good condition, and the dead battery isn’t beyond saving, the dead battery should begin receiving a charge within a few minutes.

Step 4: Start the Dead Car

Try starting the car with the dead battery. If it doesn’t start immediately, let the running car continue to idle for a few more minutes, then try again.

• Note: If the dead car still doesn’t start, the battery may be too depleted or faulty, and you may need a new battery.

Step 5: Disconnect the Jumper Cables in Reverse Order

Once the dead car starts, leave both vehicles running and follow these steps to safely disconnect the cables:

1. Disconnect the black cable from the metal surface on the previously dead car.
2. Remove the black cable from the negative terminal on the good battery.
3. Disconnect the red cable from the positive terminal on the good battery.
4. Finally, remove the red cable from the positive terminal on the dead battery.

Ensure the cables don’t touch each other or any other part of the engine once they’re removed.

Step 6: Keep the Engine Running

After the jump start, allow the revived car to run for at least 15–30 minutes. This gives the alternator time to charge the battery. If possible, take the car for a short drive to help ensure the battery holds its charge.

Tips and Considerations

• Inspect Battery Terminals: Corroded terminals can prevent a successful charge. Clean them with a wire brush if needed.
• Check Battery Health Regularly: If your battery has been dying frequently, consider having it tested or replaced.
• Avoid Jump-Starting in Hazardous Conditions: Be cautious of extremely cold weather or wet conditions, as this can create additional risks for shock or slipping.

Troubleshooting Common Issues

If the jump start didn’t work, it could be due to several issues:

• Loose or corroded cable connections can interfere with the charge.
• A completely dead battery may not respond to a jump and may need a replacement.
• Alternator issues could prevent your car from staying charged even after a successful jump.

Final Thoughts

Having the right knowledge on how to jump-start your car battery with another car is a useful skill that can save you a lot of time and money. With the right tools, a bit of patience, and a systematic approach, you can get back on the road quickly. Just remember to inspect your battery health regularly and replace it when it shows signs of frequent drainage. Happy driving!