Choosing the right size of battery cable for a vehicle, machinery, generator, or RV can be more tricky than choosing the right size of a standard battery cable. This guide is designed to assist you with your choice.

Common Sizes Of Battery Cables

Battery cables usually come in sizes between 10 AWG and 4/0 AWG. Here are all the sizes of battery cables you will typically find with a diameter and common ways to use them:

10 Gauge (AWG)

• Diameter: ~0.1019 inches (2.59 mm)
• Use: This is a usual choice for starter trigger wires, low-power alternators, and accessory leads that provide power for radio, GPS, and interior lights. It is commonly found in wiring for headlights, horns, or small 12V systems. It can handle up to 30 amps, making it suitable for smaller systems where lower currents are expected.

 8 Gauge (AWG)

• Diameter: ~0.1285 inches (3.26 mm)
• Use: 8 gauge battery cables are a choice for alternators and accessory leads. It is typically used for smaller 12V systems such as motorcycles, ATVs, or lawnmowers. Long tractors are also a possibility. It can handle up to 40 amps of current, sufficient for low-power accessories or smaller vehicles. The cable is color-coded in black, while most sizes of battery cables are red.

 6 Gauge (AWG)

• Diameter: ~0.162 inches (4.11 mm)
• Use: Great for higher-amperage alternators up to 100 -120 amps. Other applications include four-cylinder motorcycles and garden tractors. Also works as a battery cable for ATVs and subcontacts. Can also be used for light-duty automotive applications, including powering accessories such as lighting, radios, and small auxiliary car equipment. Finally, you can wire a golf cart with this cable. It can handle up to 55 amps.

4 Gauge (AWG)

• Diameter: ~0.2043 inches (5.19 mm)
• Use: Commonly used for medium-duty automotive applications, including connecting the battery to the starter or alternator. Suitable for low-compression four cylinders. It is used as an automotive battery cable for vehicles with moderate current demands, handling up to 70-85 amps.

2 Gauge (AWG)

• Diameter: ~0.2576 inches (6.54 mm)
• Use: A cable for high-compression four-cylinder and six-cylinder engines. It is used for heavy-duty applications such as larger trucks, SUVs, or marine applications (common wire size for marine battery cables). It is also common in industrial machines and heavy equipment. It connects the battery to the starter or winches and can handle up to 125 amps.

1 Gauge (AWG)

• Diameter: ~0.2893 inches (7.35 mm)
• Use: Common in 6-cylinder or V8 automotive engines, power converters, and alternators. It is also ideal for high-demand automotive applications like off-road vehicles, winches, and RVs. It is often used when high current is needed, such as battery-to-battery or inverter setups. It can handle up to 150-175 amps.

1/0 Gauge (AWG) (0 Gauge)

• Diameter: ~0.3249 inches (8.25 mm)
• Use: Also used in 6-cylinder or V8 automotive engines. Common in high-current automotive applications, such as powering large winches or RV electrical systems. Can be used in alternative power, including wind turbines and solar equipment, as long as allowed by local codes. It can handle up to 250 amps and is often used for the main battery cables in heavy-duty vehicles. 1/0 gauge is also another common size for marine battery cables.

2/0 Gauge (AWG)

• Diameter: ~0.3648 inches (9.27 mm)
• Use: Mostly used in large V8 diesel engines. Also used for industrial and marine applications that require very high current, such as powering large equipment or heavy-duty truck systems. It can handle up to 300 amps.

3/0 Gauge (AWG)

• Diameter: ~0.4096 inches (10.4 mm)
• Use: Most commonly used for the largest diesel engines (tractor trailers, large tractors), marine diesel engines, and diesel engine hard start kits. This size is used for extremely high-current applications, such as heavy-duty industrial machinery, large off-grid battery banks, or backup power systems. It is often used in commercial trucks, buses, large RVs, and marine vessels. It can handle up to 350-400 amps and is typically used when minimizing voltage drop is critical, such as long cable runs in high-power systems.

4/0 Gauge (AWG)

• Diameter: ~0.4600 inches (11.68 mm)
• Use: Used for the most extreme applications, such as industrial machinery, large off-grid solar battery banks, or backup power systems. Also good in high-power alternative battery banks. It can handle up to 400-600 amps, depending on the application and insulation. It is rarely used in automotive applications aside from over-the-road diesel trucks and large construction tractors.

Common Questions

What dia is 3 gauge car battery cable?

The diameter of a 3-gauge (AWG) car battery cable is approximately 0.2294 inches (5.83 mm).

What dia is 6 gauge car battery cable?

The diameter of a 6-gauge (AWG) car battery cable is approximately 0.162 inches (4.11 mm).

What dia is 7 gauge car battery cable?

The diameter of a 7-gauge (AWG) car battery cable is approximately 0.1443 inches (3.66 mm).

What gauge for 12 V Battery?

The appropriate gauge for a 12V battery depends on the current draw (amperage) and the length of the cable. Here's a general guide to help you choose the right gauge for a 12V battery system based on current and cable length:

Recommended Battery Cable Gauge for 12V Systems:

What is a 100 amp copper battery cable size?

For a 12V system with a 100-amp load, cable size depends on distance. Use 4 AWG for short runs (up to 7 feet), 2 AWG for moderate distances (7-10 feet), and 1/0 gauge for longer distances (over 10 feet) or continuous high-draw applications. Choosing a thicker cable for longer runs helps minimize voltage drop and prevents overheating. For maximum safety, 1/0 gauge provides the safest margin at 100 amps.