What is the cross-sectional area of car battery cables?

[Andy]

For small passenger vehicles, the national standard recommends pure copper cables with a cross-sectional area of 16 square millimeters. However, for large engineering vehicles, the recommended national standard is 25 square millimeters of pure copper. If the cable size falls below the recommended value, it may be difficult to jump-start the engine. With constant power and voltage, thicker cables have lower resistance, ultimately delivering greater current to the starter motor. Additional information: Precautions for using car batteries: Ensure the auxiliary battery is 12V and the negative terminal is properly grounded. Of course, all unnecessary lights and accessories should be turned off to prevent electrical accidents. Never reverse the polarity of the cables, as this may cause sparks during connection. Additionally, make sure the cables are tightly secured to both battery terminals (for full contact) to avoid sparking during the jump-start process.

[MacJohn]

I used to drive a Volkswagen and had to replace the battery cable. The original factory cable was about 20 to 25 square millimeters. For regular family cars like sedans, cables between 16 to 25 square millimeters are sufficient. However, SUVs or trucks with larger engines require 30 to 35 square millimeters because they need to handle high currents during startup. I had a terrible experience with using undersized cables—once I cheaped out and installed an 18 square millimeter cable, which overheated and smoked during startup, nearly burning out. If the cable is too thin, it can overheat when the current is too high, affecting the battery and even the entire electrical system. Now, I always choose high-quality copper-core cables and leave some margin for safety. Regularly checking for loose or corroded cable ends and tightening them with a wrench can extend their lifespan. The car runs much smoother now, without worrying about stalling halfway.

[StCooper]

The cross-sectional area of battery cables directly determines their current-carrying capacity, similar to the diameter of a water pipe. For regular vehicles, 16 to 25 square millimeters is typical, supporting around 100 amps of starting current. Off-road vehicles require 35 square millimeters or more to handle greater engine loads. Undersized cables can overheat and shorten battery life—I've researched that wire expansion under high temperatures combined with heavy current poses greater risks. Pure copper cables are the top choice for their excellent conductivity and durability. In winter when wires become brittle at low temperatures, flexible materials should be selected to prevent breakage. Always measure old cable dimensions or consult the vehicle manual before replacement—never guess blindly. Safety comes first; proper maintenance makes vehicles more reliable and cost-effective.

[VonArianna]

I've been driving for decades, and the battery cables used to be thinner but are much thicker now. I've asked repair shops, and for regular family cars, the cables range from 16 to 25 square millimeters, with 20 being a standard size. Never replace them with thinner cables on your own, as insufficient current can make starting difficult or cause electrical issues. For older cars, always check the manual to confirm—SUVs and similar vehicles typically use 35 square millimeters. If the cables are aged and cracked, replace them immediately to avoid short circuits. A simple DIY operation: disconnect the battery's negative terminal, remove the old cable, install the new one, and tighten it securely.