Your car battery could be too weak to start your car for a number of reasons: a faulty alternator, lights left on, cold weather or simply because the battery is old, which can no longer store enough power. Whatever the cause, you can use jumper cables to connect your dead battery to a live vehicle battery of the same size. The live battery will then charge your dead battery, enough to start the car again.
Step
Step 1. Park the donor vehicle (live battery) next to the vehicle with the dead battery
Position the vehicle so that the two batteries are as close as possible, but make sure the two cars do not touch each other.
Step 2. Turn off the radio, headlights, interior lights, and--if safe--emergency lights--in both vehicles
Step 3. Turn off both vehicles
Apply the parking brake and switch the transmission to park or neutral mode (automatic or manual transmission, respectively).
Step 4. Identify the positive and negative battery terminals
The wire leading to the positive battery terminal is almost always red. If you are in doubt, the battery itself has "+" and "-" signs to mark its positive and negative terminals.
Step 5. Separate the jumper cable clamps so there is no risk of them touching each other--this could cause a short circuit
Step 6. Clamp one of the red clamps securely to the positive terminal of the dead battery
Make sure the clamps are securely attached to the battery terminals.
On some vehicles, you may have to remove the plastic cover of the positive battery terminal before you can connect it
Step 7. Secure the other red clamp to the positive terminal on the donor battery
Again, make sure the clamps are securely connected and will not slip due to vibrations in the engine compartment.
Step 8. Connect one of the black jumper cable clamps to the negative terminal on the donor battery
Step 9. Attach another black clamp to an unpainted metal surface in the engine compartment of a vehicle with a dead battery--the farther it is from the battery, the better
- An unpainted bolt on the engine block is an ideal choice. Remember, the clamp must be able to "bite" securely on the object and hold it in place, even if the engine vibrates.
- You could, theoretically, connect a second black clamp to the negative terminal on a dead battery instead. But this will produce a spark, which can ignite hydrogen fumes from the battery.
- Make sure that no part of the jumper wires--or equipment, or battery cover--dangles into the engine compartment, where it is likely to get caught in fan belts, pulleys or other moving parts.
Step 10. Start the donor vehicle and let it sit for a few minutes before you try to start the car with a dead battery
Run the RPM all the way to about 3,000 when you try to start the car with the dead battery.
Step 11. Disconnect the jumper wires in the following order after you can start the car with the dead battery:
- Negative ground (engine block bolt or, less recommended, negative terminal on a dead battery).
- Negative terminal (black clamp) on the donor battery.
- Positive terminal on donor battery.
- Positive terminal on a previously dead battery.
Tips
- Leave the car with the new battery running for at least 15 minutes to allow the alternator to charge the battery.
- Don't turn off the car you've just battery-charged until you're in a safe location or have a chance to fish it again; depending on the condition of your battery and the alternator, which charges the battery, you will likely need to lure the car battery back up.
- Some vehicles have a plastic cover all over the battery, which you must remove before you can start fishing for the car battery or use it to lure other vehicle batteries. The cover can usually be removed easily by hand or a regular screwdriver. Check under your hood before it becomes a problem, to see if you need to keep a screwdriver or other tool in the car, just in case.
Warning
- Never fish for a frozen battery; the battery may explode. If the side of the battery protrudes, it's likely that the battery has frozen. Some types of batteries also have an indicator to show whether the liquid inside has frozen or not.
- The car battery emits hydrogen gas; if there is enough gas, a stray spark can ignite it. Connecting the jumper wires in the proper order and connecting the negative lead to the receiving battery on the engine block section, not the battery itself, reduces the risk of sparks and thus, avoids explosion.
- Always lure one 12-volt battery with another 12-volt battery; using a stronger battery can damage your car's electronics.
