Basics · 4 min watch

Jump-start a dead battery safely

Jumper cables are simple until you hook them wrong. Do it right and you'll avoid sparks, ruined electronics, and a tow you didn't need.

What you'll learn

  • The correct red-then-black clamp order (and why it matters)
  • Why the last clamp goes on a bare metal point, not the dead battery
  • When a jump-pack beats a cable-to-cable jump
  • Signs that the alternator is bad and a jump will not fix the car

Step by step

  1. Pull the donor car close enough for the cables to reach. Both cars OFF.
  2. Clamp RED to POSITIVE (+) on the dead battery.
  3. Clamp RED to POSITIVE (+) on the donor battery.
  4. Clamp BLACK to NEGATIVE (−) on the donor battery.
  5. Clamp BLACK to bare metal on the dead car's engine block (not the battery).
  6. Start the donor. Wait 2 minutes. Start the dead car. Let run 10 minutes before driving.
Safety note

If the car cranks weakly or dies again within an hour, the alternator or battery has failed. A second jump will not help — call for a tow to a shop.

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