What You Need

  • Jumper cables (keep a set in your car at all times)
  • A working car with a charged battery
  • Both cars parked close enough for cables to reach (but not touching each other)
Important safety rulesNever connect positive to negative. Never jump start a cracked, leaking or frozen battery. Make sure both cars are off before connecting cables. Keep cables away from moving engine parts.
  1. 1

    Park the working car close to the dead car

    Position the cars so the batteries are close — either nose to nose or side by side. They must not be touching each other.

  2. 2

    Turn both cars off

    Make sure both cars are completely off with the keys out before connecting any cables.

  3. 3

    Connect RED to dead battery positive (+)

    Clamp one red cable to the positive terminal of the dead battery. The positive terminal is usually marked with a + symbol or has a red cover.

  4. 4

    Connect RED to working battery positive (+)

    Connect the other end of the red cable to the positive terminal of the working battery.

  5. 5

    Connect BLACK to working battery negative (–)

    Clamp one black cable to the negative terminal of the working battery.

  6. 6

    Connect BLACK to bare metal on the dead car

    Do NOT connect to the dead battery negative terminal. Instead, clamp to an unpainted metal surface on the engine block or chassis of the dead car — this prevents sparks near the battery.

  7. 7

    Start the working car and wait 2 minutes

    Let the working car run for 2 minutes to transfer some charge to the dead battery.

  8. 8

    Try to start the dead car

    Attempt to start the car with the flat battery. If it does not start, wait another 2 minutes and try again. If it does not start after 3 attempts, the battery may need replacing.

  9. 9

    Disconnect cables in reverse order

    Remove black from dead car, black from working car, red from working car, red from previously dead car.

  10. 10

    Drive for at least 30 minutes

    Drive (do not idle) for at least 30 minutes to let the alternator recharge the battery. Short trips will not recharge it enough.

Recurrent flat battery?If your battery keeps going flat, it likely needs replacing. Most car batteries last 3–5 years. Get it tested at a battery shop — testing is usually free.

Frequently Asked Questions

Yes, but be careful with cars that have start-stop technology or complex electronics. Check your car manual — some manufacturers recommend connecting to specific jump start terminals rather than directly to the battery.
A portable jump starter (also called a jump pack) is a worthwhile investment — about $60–100. It fits in your glovebox and lets you jump start without needing another car. Highly recommended.
Either the battery is too old and depleted to hold a charge, or you did not drive long enough to recharge it. Get the battery and alternator tested at a workshop.