Sakura SS3625 200A

These insulated 3-metre cables have a 25 mm² cross-section, enough to handle up to 200 A. They will jump-start vehicles with an engine displacement of no more than 2 litres, typically small and mid-size petrol city cars. The alligator clips are sturdy and grip terminals well, though they can be a little large on small, hard-to-reach batteries such as those on some motorcycles. For a tight budget, they make an effective backup.

The 25 mm² section and 3-metre length set the scope of use: this light, compact format tucks easily into the boot, but it means parking the two vehicles close, bonnet to bonnet, because the cable does not forgive long distances. For a large diesel, an SUV or a van, a heavier cross-section, 35 mm² and up, that carries more amps is a better choice; here, you stay with small and mid-size engines.

As for method, a successful jump-start comes down to a few simple steps. Connect the + of the flat battery to the + of the donor battery, then the - of the good battery to a metal earth point on the stranded vehicle, away from the battery to avoid any spark near the gases. Start the car supplying the current, wait a moment, then start the flat one before disconnecting everything in reverse order.

After use, a cable that is coiled and kept dry lasts a long time: moisture is the main enemy of copper and clamps. An occasional visual check of the insulation and the jaws is enough to make sure it stays reliable the day you really need it. At this price, it is inexpensive peace of mind to keep in the car at all times.