How to boost a car battery

Common signs your battery is dying include:

• Battery warning light is on.
• Starter makes a loud thumping or ticking sound.
• Engine is slow to crank.
• Headlights are dim or flickering.
• Charging ports have no power.

Check out this article for more tips on how to spot a dying battery.

Many things can cause your battery to die, such as loose or corroded battery connections, extreme temperatures, taking too many short trips, or leaving the lights on too long.

Some of these causes are avoidable. For example, you can give the alternator enough time to charge the battery by taking fewer quick trips. Other times, you may realize too late that you forgot to turn your lights off before heading into the grocery store for a big shop.

To successfully (and safely) boost your battery, you’ll need:

• a set of booster cables, like these, or a booster pack, like this
• a second vehicle (if using jumper cables)
• a multimeter
• protective gloves and glasses

Check out this article to learn about the differences between jumper cables vs. a booster pack. If you can’t jump-start your car on your own, call a roadside assistance service, like CAA.

If you can use a second vehicle to jump-start your battery with jumper cables, follow these steps:

1. Park the vehicles near each other (but not touching) with the ignitions off.
2. Connect one end of the positive cable (red) to the positive terminal on the dead battery. Attach the other positive clip to the positive terminal on the donor battery.
3. Connect one end of the negative cable (black) to the negative terminal on the donor battery and the other negative clip to a grounded metal component on the car with the dead battery, such as the shock tower bolts, frame, or chassis.
4. Turn on the car with the donor battery.
5. Leave the cars connected for at least five minutes.
6. Try starting the car with the dead battery. If it doesn’t turn on, wait another five minutes, then try again.
7. Once the car with the (previously) dead battery turns on, disconnect the cables in the reverse order you connected them.
8. Let the car run for 30 minutes. You can drive. Just don’t turn the vehicle off.

To boost your battery with a booster pack, follow these steps:

1. Connect the cable clamps to the battery terminals the same way you would connect jumper cables: positive to positive and negative to negative.
2. Activate the booster pack (if necessary).
3. Start your vehicle. If the car doesn’t turn on, wait a minute and then try again.
4. Once the car is running again, disconnect the clamps in reverse order.
5. Let the car run for 30 minutes.

Booster pack instructions may vary. Read all the information that comes with the booster pack before attempting to use it. Remember to recharge the pack between uses.

After jump-starting your vehicle, determine how dead the battery is before you fully recharge it. You can do this with a multimeter. If it reads below 12 volts, jump-start it again. If it still reads below 12 volts, you’ll need a replacement battery. Once the battery reaches 12 volts or higher, go for a 30-minute drive so your vehicle’s alternator can finish charging it.

Most car batteries will need to be replaced after three to five years. If your battery needs frequent jump starts or won’t hold a charge of at least 12.6 volts, it’s likely dead and should be replaced. We have a full guide on how to replace your battery here. To learn about what batteries are available, visit this page.

If you have any questions about boosting or replacing your battery, visit a NAPA Auto Parts store to speak with an expert.