How to jump start a car
It’s an underrated automotive survival skill that you might not have thought about since learning the basics at drivers education. So what is your roadside assist technician doing under your bonnet when you call with a flat battery, and do you have the know-how to safely jump start a car yourself?
A word of caution
Jump starting a vehicle is not without risk. Dealing with batteries and electrical components carries an inherent risk of electric shock, and using incorrect equipment or methods can cause expensive damage to vital electric components of your vehicle. If you’re stuck with a flat battery and need to get to us for a replacement, we recommend you call a reputable roadside assistance service to jump start your vehicle for you. It’s always safer to leave a jump start to an expert!
Help, my car won’t start!
So you’re ready for work; lunch packed, seatbelt on and…your car won’t start. It’s not a great feeling, but we’ve got a few handy tips to help you work out what might be wrong. If you hear nothing at all when you turn the ignition, chances are you’ve got a flat battery on your hands. Now is the time to call roadside assist, who are best placed to jump start your car quickly and safely so you can get your vehicle to us for a replacement battery. But what is the technician doing when they jump start your car, or what happens if roadside assist isn’t an option for you?
What is a jump start?
A jump start is a method of starting a vehicle with a discharged or flat battery by using a temporary ‘boost’ from another vehicle’s battery or an specialised external power source. To jump start a car with leads, you will need:
- A set of surge-protected jumper cables
- A power source, usually another vehicle with charged battery of matching voltage (the ‘booster’ vehicle) or battery charger
Jump starting a car with leads
Before attempting to jump start a car with leads, always check your owner’s manual for advice. Some vehicles are not suitable for jump starting, and others may have special requirements. Electric vehicles and vehicles with complex electrical control units may not be suited to standard jump start methods. Never attempt to jump start a vehicle with a corroded, leaking or visibly damaged battery.
- Check the battery in your booster vehicle. Does the voltage on the booster vehicle match the voltage on your drained (or ‘dead’) vehicle (e.g. both batteries are 12V)?
- Prepare the vehicles. Park the cars in a safe and well-ventilated location nose-to-nose. The vehicles should be far enough apart for you to safely move between them, but close enough that the cables can reach from battery to battery. Ensure handbrakes are engaged, and that both vehicles are in neutral (for manual transmission) or park (for automatic transmission). The ignition and all electrical accessories on both vehicles should be switched off.
- Open the bonnets of both vehicles.
- Carefully attach the jumper leads to the batteries in the correct order. It is very important to not allow any of the clips to touch one another during this process.
- Red to dead. Connect a red (positive) clip to the positive terminal (marked POS or +) on the battery of the dead car.
- Red to booster. Connect the other red (positive) clip to the positive terminal (marked POS or +) on the battery of the booster car.
- Black to booster. Connect a black (negative) clip to the negative terminal (marked NEG or -) on the battery of the booster car.
- Black to dead metal. Connect the other black (negative) clip to a stationary and unpainted metal part of the dead car, away from the battery. This is an important safety step to ensure that any sparks produced do not occur near the battery itself. Be extra careful not to touch the clips together at this point.
- Start the engine of the booster vehicle. Idle the engine of the booster vehicle for 3-4 minutes.
- Start the engine of the dead vehicle. Idle the engines of both vehicles for at least 10 minutes.
- Turn both engines off. This is important to prevent any voltage spikes that may damage electrical components in both vehicles.
- Carefully disconnect the jumper leads in reverse order. Again, be very cautious to not allow any of the clips to touch one another during this process.
- Black from dead metal
- Black from booster
- Red from booster
- Red from dead
- Attempt to start the dead vehicle. If the vehicle starts, it’s time to bring it down to Cox Auto so we can change your battery over for you and check for any other faults. If the vehicle does not start, try jump starting the vehicle once more. If the vehicle still doesn’t start, the battery may be too flat or damaged to be jump started.
Your car can also be jump started with a specialised jump starter kit. You won’t be able to jump start with a battery charger, however it can replenish a fully dead battery within 24 hours. We recommend referring to your owner’s manual and the instructions on your equipment before operating.
Caring for your battery
So now you know how to jump start a car, what can you do to avoid needing to do it?! We regularly check battery health as part of your car’s regular servicing and maintenance program, so if you find yourself calling roadside assist to jump start your car, let us know and we’ll take care of you and your car. Our specialist technicians make sure both you and your car receive a premium service experience so that you can relax and focus on the things that matter most.