Being stuck with a flat battery is never ideal — especially when you're in an unfamiliar place. But with the right know-how, you can confidently get back on the road. Knowing how to jump start a car isn’t just a handy trick — it’s a fundamental skill that can save you time, money, and a call to roadside assistance.
This guide will walk you through the essentials — from battery basics to safe, step-by-step jump start instructions. Whether you’re an experienced driver or just getting started, you’ll gain the confidence to act quickly and safely when your battery lets you down.
Why Your Battery Might Be Flat
A flat or discharged battery is one of the most common reasons a car won’t start. It usually happens when power is drawn while the engine’s off — for example:
- Leaving headlights on overnight
- Listening to the radio at the drive-in
- Not driving for an extended period
You might hear a clicking sound when you turn the key, but the engine won’t crank. This is often a clear sign your battery needs a jump — especially if it's an older battery or it's cold outside, which can reduce its effectiveness.
What Is Jump Starting?
Jump starting is a temporary solution that uses another power source — usually a second vehicle or a portable jump starter — to give your battery the charge it needs to start the engine.
Once your car is running, you can drive it to a safe location or recharge the battery properly.
However, jump starting won’t fix a discharged battery — it's just a short-term workaround.
Safety First: Before You Begin
Jump starting involves electricity, which means safety should always come first. Done incorrectly, it can cause damage to you or your vehicle. Here’s what to keep in mind:
- Wear protective gloves and safety glasses
- Check both vehicles are in Park (or Neutral) with the handbrake engaged
- Turn off the ignition in both vehicles
- Never jump start a cracked, leaking, or damaged battery
- Avoid clamping onto battery terminals with current sensors
- Only use manufacturer-recommended jump points when available
If you’re unsure, don’t take the risk — contact a professional.
What You’ll Need
To jump start a car, you’ll need one of the following:
- A pair of heavy-duty jumper cables
- A donor vehicle with a healthy battery
- OR a portable jump starter (recommended for safety and convenience)
💡 Pro Tip: Portable jump starters are safer and often include features like reverse polarity protection. Speak to your local R&J Batteries branch to find out which option is best for your vehicle.
Step-by-Step: How to Jump Start a Car
- Check the battery condition — Never jump a battery that’s damaged, leaking, or emitting gas.
- Confirm both vehicles use the same voltage — Most passenger vehicles are 12V.
- Remove the keys from the ignition of the disabled vehicle — This gives you full control.
Connecting Jumper Leads:
- Connect red (positive) cable to the positive terminal of the dead battery, or to its jump point if available.
- Connect the other end of the red cable to the positive terminal of the donor vehicle’s battery.
- Connect black (negative) cable to an unpainted metal surface on the dead vehicle (e.g. engine block).
- Do not connect directly to the negative battery terminal.
- Connect the other end of the black cable to the donor vehicle’s negative terminal or an unpainted metal surface.
- Start the donor vehicle (or activate the jump starter). Wait 2 minutes.
- Start the disabled vehicle — leave both vehicles running for at least 2 minutes.
Disconnecting:- Remove the negative cable from the dead vehicle first, then from the donor vehicle.
- Remove the positive cable from both vehicles.
- Turn off the donor vehicle — keep the now-running vehicle going.
After You’ve Jump Started
A 20-minute drive won't fully recharge a flat battery. While your car’s Battery Management System may help, it’s not enough to restore a heavily discharged battery.
For best results:
- Use a quality, mains-powered multi-stage charger
- Charge the battery overnight at the recommended rate (e.g., a 75Ah battery should charge at no more than 7.5A)
Prolonged undercharging can lead to
sulphation, a condition that shortens battery life and limits performance.
Final Thoughts
Learning how to jump start a car is more than just helpful — it’s empowering. You’ll feel more confident in emergencies and more in control of your time and safety.
Just remember:
- Follow each step carefully
- Always consult your vehicle’s manual
If in doubt, seek professional help
🔋 Need help choosing the right battery or jump starter? Your local RedPoint team is here to help.
