How to Jumpstart Your Car Safely (Without Damaging the Battery)

Jump Starting Your Car Safely

Jumpstarting a vehicle is a skill every driver should have, but it is also one that is frequently done, sometimes with costly consequences. Modern vehicles are packed with sensitive electronics, and connecting the jumper cables in the wrong order can damage the ECU, blow a fuse, or worse.

What You Will Need

• A set of jumper cables rated at least 400 amps.
• A second vehicle with a charged battery of similar voltage, typically 12V for most passenger cars.
• Alternatively, a portable jump starter pack, which allows you to jumpstart without a second vehicle.

Before You Start: Safety Checks

• Inspect the flat battery visually. If it is cracked, leaking, bulging, or giving off a strong smell, do not attempt to jumpstart it.
• Make sure both vehicles are switched off before connecting cables.
• Ensure the two vehicles are not touching each other metal-to-metal.
• Keep the jumper cables away from any moving parts like fans or belts.

Step-by-Step: How to Jumpstart Correctly

Step 1: Position the vehicles

Park the working vehicle nose-to-nose or side by side with the dead vehicle so the jumper cables can comfortably reach both batteries.

Step 2: Identify the battery terminals

Locate the batteries in both vehicles. Each battery has a positive terminal marked with a plus sign, typically with a red cover, and a negative terminal marked with a minus sign, typically black.

Step 3: Connect the jumper cables in the correct order

First: Connect the RED cable to the POSITIVE terminal of the FLAT battery.
Second: Connect the other end of the RED cable to the POSITIVE terminal of the GOOD
battery.
Third: Connect the BLACK cable to the NEGATIVE terminal of the GOOD battery.
Fourth: Connect the other end of the BLACK cable to an unpainted metal surface on the dead vehicle, away from the battery.

Step 4: Start the working vehicle

Start the vehicle with the good battery and let it run for two to three minutes before attempting to start the dead vehicle.

Step 5: Start the dead vehicle

If it does not start after a few seconds, wait another two minutes and try again. Do not crank the starter
motor for more than five to ten seconds at a time.

Step 6: Disconnect the cables in reverse order

First: Remove the BLACK cable from the unpainted metal on the revived vehicle.
Second: Remove the BLACK cable from the NEGATIVE terminal of the good battery.
Third: Remove the RED cable from the POSITIVE terminal of the good battery.
Fourth: Remove the RED cable from the POSITIVE terminal of the revived battery.

Step 7: Drive the revived vehicle

Drive it for at least 20 to 30 minutes at varying engine speeds to allow the alternator to recharge the battery properly.

When a Jumpstart is Not Enough

If your battery goes flat repeatedly, a jumpstart is only a temporary fix. Our guide on how to identify weak or failing car batteries covers the early signs that your battery, rather than a one-off drain, is the real problem.

A battery test at a reputable fitment centre will tell you whether the battery itself is faulty or whether the charging system is the issue. AAA's guide to battery maintenance also has useful tips on extending battery life once you're back on the road.

Portable Jump Starters: A Smarter Alternative

A portable jump starter pack is one of the most useful pieces of kit you can keep in your vehicle. These compact lithium battery packs can jumpstart a car without the need for a second vehicle.

The Bottom Line

Knowing how to jump-start a car correctly is a fundamental motoring skill every South African driver should have. It's also worth remembering that many MotorHappy motoring Plans include Roadside Assistance, including jumpstart support, so you're never entirely reliant on doing it yourself.

Sources & Further Reading:

• AAA: Battery Maintenance 101