Need a car jumper cable or want to know how to connect a jumper cable correctly? On this page more information about jumper cables and how you can connect them safely. Starting cables are used when your car does not start because the battery is empty. In such a case, you can ask for help from another motorist with a car of a similar size to yours. They will most likely have a battery with the same capacity as yours. You can then use a jump lead to start your car on the other car's battery. Below is a step-by-step plan for the correct connection of the jumper cables.

Correct car jump lead

jumper cablesJumper cables are used to generate enough voltage to start the engine of the faulty vehicle so that it can then continue charging the battery on its own. What sounds simple in theory requires the right approach in practice. Diesel Engines are more powerful than petrol engines, which is why the required amperage is higher for diesel cars. Therefore, to withstand the current to be transferred, the jumper cable for a diesel vehicle must have a thickness of at least 25 square millimetres. Thinner cables are not suitable for this and thus do not provide sufficient protection to the user. Therefore, starting assistance may fail or, in the worst case, damage to the vehicle or injury to the user may occur if a cable that is too thin is used. Jump leads for petrol cars In contrast, only 16 mm² need be thick, as the current is weaker in this case.

When using jumper cables for starting problems, make sure the vehicles do not touch each other!

Connecting the jumper cables:

  • Turn off the engine of both vehicles
  • Switch off all power consumers (such as radio, heating, air conditioning, etc.).
    • 1: Connect the positive terminals of both batteries by connecting the red cable to the +pool of the flat battery.
    • 2: Then connect the red cable to the +pool of the good battery
    • 3: Connect the black cable to the -pool of the full battery.
    • 4: Attach the other black clip to MASSAGE of the breakdown vehicle, e.g. a metal part of the engine or (unpainted) bodywork part.
  • Start the car engine with the battery fully charged
  • Run the engine at a slightly higher speed

You can try to start the vehicle's engine immediately or wait a few minutes to do so. If starting the breakdown vehicle is successful, wait a few more minutes before disconnecting jumper cables. Please note that when disconnecting the cables, a peak voltage may occur. After starting the auxiliary vehicle, switch on the rear window heater and heater (temporarily) to accommodate the high charging current.

Disconnecting the jumper cables:

  • First disconnect the black jump leads from the body of the car with a flat battery.
  • Remove the black terminal from the -pool of the full battery.
  • Now disconnect the red battery terminal from the +pool of the good battery
  • Finally, remove the red terminal from the +pool of bad battery

Make sure that the red and black cable clamps do not have contact with each other at any time.

Now that the car has started, it is important not to turn the vehicle off immediately but to drive it for a few kilometres so that the alternator can generate enough current for the battery. You can also connect a car charger to the battery. However, a short drive in city traffic is not enough to charge the battery.

Buying the right jumper cables

If you need jumper cables unexpectedly, you cannot use just any cable. Which jumper cables you can use depends on the type of car, length, thickness and core material of the cable. Do you drive petrol? Then our 16-millimetre jumper cables are suitable. Do you have a diesel car? Then jump leads of 25 millimetres are perfect. Tip: if you use your jumper cable in a breakdown situation, find a rescue car that runs on the same fuel as your car so that the jumper cable also works on the other car battery.

Always use jumper cables wisely and responsibly. Possibly under the guidance of an expert. Using jumper cables is always an emergency solution and it means something is wrong with the battery. It is necessary to charge the battery with a proper battery charger and otherwise replace it for a new battery. So our advice is to replace the battery for a new one as soon as possible!

Alternative to cables: battery booster / jump starter

Short circuits caused by using a jumper cable do not occur easily, as long as you know what to watch out for. Nevertheless, for example in vehicles that only drive short distances or have not been used for a long time, it is necessary to charge the battery not with jumper cables but with an external charger. Sometimes you do not need the whole jumper cable, but only the battery terminals. There are many different products for sale, from individual clamps in red or black to whole sets. These clamps are not suitable for all voltages. Therefore, always read the product info carefully to find out how many amps (A) the battery clamp or battery clamp set you have chosen is suitable for. This differs per vehicle category; for example, there is often a difference between diesel and petrol engines.

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