Note: costs mentioned below are given in US dollars as a general point of reference — actual prices vary by country, currency, and local market.
Connect jumper cables in this order: red to dead battery positive, red to donor positive, black to donor negative, black to an unpainted metal surface on the dead car (not its negative terminal) — this keeps sparks away from the battery itself. Let the donor car run for a couple of minutes before attempting to start the dead one, and once it's running, drive for at least 15-20 minutes to let the alternator recharge the battery. Never jump-start a battery that's cracked, swollen, or leaking.
At a glance
| Item | Detail |
|---|---|
| Typical car battery voltage | 12V lead-acid or AGM |
| Safe running time after jump | 15-20 minutes minimum driving |
| Portable jump starter cost | $50-150, no donor car needed |
| EV/hybrid caution | Only the 12V auxiliary battery is jump-started, never the high-voltage pack |
Before you touch a single cable
Put both cars in park (or neutral for manuals) with parking brakes on and engines off. Put on safety glasses if you have them — batteries can vent small amounts of hydrogen gas, and while a jump-start rarely causes a bang, it's not zero risk. Check that your jumper cables aren't frayed or corroded at the clamps, since a bad connection is the most common reason a jump-start fails.
The correct cable order
- Red (positive) clamp onto the positive terminal of the dead battery.
- Red (positive) clamp onto the positive terminal of the donor (working) battery.
- Black (negative) clamp onto the negative terminal of the donor battery.
- Black (negative) clamp onto an unpainted metal surface on the dead car's engine block or chassis — not the dead battery's negative terminal. This gives any spark somewhere away from the battery, where hydrogen gas can collect.
Start the donor car and let it idle for 1-2 minutes to feed some charge into the dead battery, then try starting the dead car. If it doesn't catch after a couple of tries, wait another few minutes rather than cranking repeatedly — the starter motor overheats fast.
Removing the cables
Disconnect in the reverse order you connected them: negative from the chassis first, then negative from the donor, then positive from the donor, then positive from the now-running car. Keep the clamps from touching each other or any metal while cables are still hot.
EVs and hybrids need a different mindset
Electric and hybrid vehicles still carry a conventional 12V battery that runs the computers, lights, and locks — that's the one you jump, and the process is the same. The high-voltage traction battery (typically 300-800V) is never jumped, isn't accessible through jumper cables, and doesn't need to be — if the 12V battery is dead, the car simply won't wake up even though the main pack is fully charged. Some EVs require a specific procedure (opening the frunk via a manual release, or connecting to a marked jump point) — check the owner's manual before assuming the process is identical to a gas car.
A battery case that's cracked, bulging, or leaking white/greenish crust should not be jump-started — it can rupture. Call for a tow or roadside battery replacement instead.
Portable jump starters vs. cable-and-donor-car
A lithium jump-start pack (roughly $50-150) skips the need for a second car entirely, charges over USB, and most can jump a car dozens of times per charge. They're worth carrying if your battery is aging, since a dead battery rarely picks a convenient parking lot with a helpful stranger nearby.
Frequently asked questions
Why does the black cable go on metal, not the battery, on the dead car?
How long should I drive after a jump-start?
Can jump-starting damage a car's electronics?
Can I jump-start an EV's 12V battery the same way as a gas car?
Sources & further reading
Figures, prices and policy details were current at the last-updated date above. Automotive pricing, incentives and regulations change frequently — verify time-sensitive details with the linked primary sources. Read our editorial policy and fact-checking standards.
