Jumper Leads & Booster Cables

Jumper Leads and Booster Cables are used to start a vehicle that has a battery in poor condition or flat. To do this you need a vehicle that is running and you connect the two batteries together using the Jumper Leads or Booster Cables. This causes extra power to flow from the running vehicle to the vehicle with the bad or flat battery. The additional power helps start the vehicle. Once running the Jumper Leads or Booster Cables can be removed. The vehicle with the bad battery runs OK as the alternator has taken over from the battery once the engine starts.

Jumper Leads and Booster Cables are like an insurance policy. Nice to have but you hope you don't need to use them. They are a handy item to leave tucked up in the boot. If your battery lets you down you can get someone to jump start you and get you back on your way. You could be the good samaritan and help jump start someone else.

When selecting jumper leads the amps (amperage) are an important guide. It is to do with engine size. The bigger the engine is the more power a battery needs to start it. Batteries are rated in CCA (Cold Cranking Amps) and the bigger the engine the greater the CCA number. Most quality jumper leads will give you a guide on the packaging as to what size engine they can start.

Leads are made from copper as it is a great conductor of electricity. The thicker the lead the more electricity or Amps can flow through it. The bigger the cars engine, the more heavy duty the leads need to be to start it, which in turn means they cost more money to buy. Long leads create more resistance to the flow of electricity so most jumper leads are short which requires the vehicles to be parked close together. Note that due to their design a smaller diesel engine may need the same size leads to start it as a larger petrol engine.

There are a few simple rules to follow when using jumper cables on a car battery. Refer to the vehicle manual which should indicate the type of booster cables required and follow their instructions. Surge protected cables are the best ones to get, especially with modern vehicle electronics. Battery voltage is important. Make sure they are the same in both vehicles. It is usually 12V but trucks and some other large vehicles have 24V systems.

When using booster cables the there are no other tools required, just the leads and the details on how to connect them. There are only 2 cables which are colour coded red for Positive (+) and black for Negative (-). The cables have insulated clamps at both ends for your safety and protection and these are designed to clip onto the battery terminals and a part like an engine block. They have teeth on them to help make good electrical contact as a poor connection is not helpful. Always connect them up in accordance with the vehicle manufacturers instructions.