How Thick Should Car Battery Jumper Cables Be?
2 Answers
Typically, 2.0*2.5 pure copper national standard wires are used, and 16 square millimeter copper wires are also acceptable. The starting current is very large, with normal working currents reaching several tens of amperes. The method for connecting vehicle jumper cables is as follows: 1. The primary task is to ensure that the auxiliary battery is 12V and that the negative terminal is already grounded. Turn off all unnecessary lights and accessories to prevent electrical accidents. 2. Follow the sequence shown in the diagram below to properly connect the jumper cables. Be careful not to reverse the positive and negative terminals of the cables, as sparks may occur when connected incorrectly. Also, ensure the cables are tightly wrapped around both battery terminals (for full contact) to prevent sparking during the jump-start process. 3. Start the engine of the car with the auxiliary battery and run it at medium speed. Then, start the engine of the car with the depleted battery.
Last time my car had a dead battery and I needed a jump start from a friend, I realized there's a lot to consider. The thickness of the cables mainly depends on the diameter of the copper core, and it's recommended to choose standard copper cables of No. 4 or above. For a temporary jump start on a small car, a No. 4 cable can handle over 200 amps, which is sufficient. From my experience running a repair shop, thicker cables ensure a more stable start. For large-displacement vehicles, at least a No. 2 cable should be used. Those ultra-thin off-brand cables are no good—they can overheat and pose a danger. It's best to choose cables with insulated rubber coating and pure copper clamps. Don’t skimp and buy low-quality products; safety comes first. And remember, never reverse the positive and negative terminals—red clamp on the positive, black on the negative.
