How to Jump a Car Battery (Cables and Lithium Jump Packs)
Step-by-step instructions for safely jumping a dead car battery — with traditional jumper cables and modern lithium jump starters.
Before you do anything
Pop the hood and confirm the battery is actually dead. If the dome light is bright and the starter clicks rapidly, the battery is low but maybe salvageable. If everything is dark and silent, you'll need a jump or a charger.
Check for visible damage — cracked case, leaking acid, swollen sides. If the battery is damaged, do not jump it. Replace it.
Make sure both vehicles (or the jump pack) are turned off and in park or neutral with the parking brake set.
Method 1: Jumping with cables and a donor car
1. Park the donor car close enough that the cables reach both batteries. Don't let the cars touch.
2. Connect the RED clamp to the POSITIVE (+) terminal of the dead battery.
3. Connect the other RED clamp to the POSITIVE (+) terminal of the good battery.
4. Connect the BLACK clamp to the NEGATIVE (-) terminal of the good battery.
5. Connect the other BLACK clamp to a clean, unpainted metal ground on the dead car's engine block or chassis — NOT directly to the dead battery's negative terminal. This reduces the chance of sparking near hydrogen gas.
6. Start the donor car and let it run for 2–3 minutes.
7. Try to start the dead car. If it cranks but won't catch, wait another minute and try again.
8. Once started, remove cables in REVERSE order: black on dead car, black on donor, red on donor, red on dead car.
9. Drive the previously-dead car for at least 20 minutes to let the alternator recharge the battery.
Method 2: Jumping with a lithium jump pack
A lithium jump starter eliminates the need for a second vehicle. The procedure is similar but safer and faster.
1. Make sure the jump pack is charged — most show a green LED when ready.
2. Connect the RED clamp to the POSITIVE (+) battery terminal.
3. Connect the BLACK clamp to a clean metal ground on the engine block, or to the NEGATIVE (-) terminal if your pack's manual allows it.
4. Power on the jump pack (some auto-detect; some have a manual override button).
5. Start the car. Modern lithium packs crank a healthy gas V8 in 1–2 seconds.
6. Power off the pack, then remove black clamp first, then red.
7. Recharge the jump pack as soon as you get home — they self-discharge slowly and you don't want a dead jump pack the next time you need one.
Common mistakes that kill batteries (and people)
Reversing the clamps. Red goes to positive, black goes to negative or ground. Reversing them can blow fuses, fry electronics, or spark a battery explosion. Good lithium packs have reverse-polarity protection — cables do not.
Letting the clamps touch each other while connected to a battery. This shorts the battery and can weld the clamps together.
Jumping a frozen battery. If the battery is visibly frozen or has been in sub-zero temperatures for days, do not jump it — it can rupture.
Driving away after a 30-second idle. The alternator needs 20+ minutes of driving to put meaningful charge back in. A short trip will leave you stranded again tomorrow.
When a jump won't fix it
If the car starts on a jump but dies as soon as you disconnect, the alternator is bad or the battery won't hold a charge. Either way, you need a shop or a new battery.
If the car won't crank at all even on a strong jump, the starter, ignition switch, or main ground cable is likely the problem. A multimeter and a few minutes of diagnosis will tell you which.
Most car batteries last 4–6 years. If yours is older and has died once, it will die again. Replace it before it leaves you stuck somewhere worse.
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