Ultimate Guide to Battery Cable Size Chart
The right battery cable size is key to properly functioning the electrical systems. Most importantly, it ensures safety by reducing fire risks. Battery cables are essential for transferring power from the battery in applications such as cars, devices, and machinery. Wrong cable sizing causes voltage drop and overheating, and it reduces its effectiveness.
Proper and accurate battery cable sizing ensures excellent power transmission, minimizes occurrences of electrical problems, and extends the battery life. Good battery cable sizing is also essential in renewable energy sectors such as solar energy. In this article, learn the best battery cable sizing practices by using the battery cable size chart.
Battery Cable Types
Battery cable is a single conductor wire made of heavy-duty copper. The cable is insulated with PVC and it links the battery to the machine’s or vehicle’s automotive parts. The parts of the battery cable are also known as battery leads. There are two major categories of leads, the negative lead and the positive lead. The positive lead links the battery to the ignition system, while the negative lead links the battery to the chassis.
There are several types of battery cables, namely:
- SGT Battery cable
- SGX Battery cable
- Marine battery cable
- CCA (copper-clad aluminum)
- Fuse link or fusible link
- OFC (oxygen-free copper)
1. SGT Battery Cable
The SGT battery cable features the THHN-type wiring coating, for thermoplastic PVC insulation. THHN means thermoplastic high heat resistant nylon coated. The insulated SGT battery cable has a 50-volt rating of 105o C or 85.
The SGT cable has a low strand count because of the higher significance of the strands. This makes the wire a little stiffer and holds in place where you have it out. However, you can bend it on tight corners.
2. SGX Battery Cable
The SGX cable is flexible and performs well under high temperatures. The cable has a soft anneal, with chemically cross-linked polyolefin insulation. It has a temperature rating of -40°C to +125°C. The insulation trade-off is stiff and thick and it features a higher strand count. If you are operating under high temperatures, SGX cable is a good choice.
3. Fusible Link
A fuse link is a fuse that resembles a wire but it acts slowly. It features high-temperature insulation that does not burn even when it is open. The fuse link is mostly used in alternator wires. It prevents the disastrous failure of the alternator diode since the alternator wire is likely going to melt without a fusible link.
4. Marine Battery Cable
Marine cables are best suited for high temperatures, submerged, or wet applications. The cables have a self-extinguishing feature with a marine rating and a legal requirement as the coast guard. A wire that lacks marine rating, should not be used for building a cable. The marine battery cable has a voltage rating of 600 volts and a temperature ranging from +105°C for dry and +75°C for wet.
5. OFC (Oxygen Free Copper)
A standard OFC wire is made up of 99.95% copper. OFC cable is expensive compared to a similar-sized standard cable. A high-quality OFC wire is approved by SAE.
6. CCA (Copper Clad Aluminum)
A CCA wire is copper-plated aluminum which is two sizes larger with optimal level conductivity. For instance, aluminum has a 60% copper conductivity level.
Understanding Battery Cable Gauge
The battery gauge also known as the voltage gauge measures the voltage of the battery. Some types of gauges come with numbers. If the gauge is reading 12 while the engine is still running, that’s an indication of an issue. The standard gauge reading must be above 13 volts and below 15 volts. The following list indicates the various battery gauges.
10-Gauge Wire
A 10-gauge wire is used for starter trigger wires, accessory leads, and low-power alternators.
8-Gauge Wire
An 8-gauge wire is a black wire rated at 40 amps. It is used for low-power alternators and accessory leads.
3.6-Gauge Wire
The 6-gauge wire is black and it’s suitable for 55 amps. It is usually used in stock alternators, wiring of golf carts, accessory leads, and battery cables for ATVs and subcompacts.
4-Gauge Wire
A 4-gauge American wire is commonly used in car battery cables, residential, and industrial applications, and in audio systems. A 4-gauge wire is rated at 160 amperes and it is suitable for alternator wiring.
2-Gauge Wire
A 2-gauge wire is usually used in high-amperage capacity applications such as industrial machinery, heavy equipment, winches, and power converters among others. The 2-gauge wire has an ampere capacity of 130 amps at 167°F, 150 amps at 90°C, and 115 amps at 60°C.
1-Gauge Wire
The 1-gauge wire is used in V8 or 6-cylinder automotive engines, power converters, and alternators ranging 200 amperes.
1/0-Gauge Wire
The 1/0-gauge wire is heavy-duty and commonly used in various electrical applications such as welding equipment, stock V8s, solar panels, marine batteries, wind turbines, and 6-cylinder engines. The 1/0-gauge copper wire has an amperage capacity of 150A and 75°C temperature.
2/0 Gauge Wire
The 2/0-gauge wire is more important than the 2 AWG wire used in the distribution of power, grounding, and transmission bonding. It has an ampere capacity of 135 amps at 60°C with a diameter of 9.27mm. The 2/0 wire is low-resistant and high-ampacity plus cable suitable for diesel engines, high-compression engines, and large RV power converter house batteries.
3/0 Gauge Wire
The 3/0-gauge wire is mostly used for diesel engines and marine applications. It is suitable for use in both damp and dry applications and it operates in up to 90°C temperatures and in wet applications at 75°C. This type of wiring is used in applications such as raceways that are exposed to sunlight.
4/0-Gauge Wire
The 4/0 -gauge wire has a 230-ampere rating at 75°C. It is used for high-power secondary battery banks. The rating of the 4/0 gauge can vary depending on whether the insulation and conducting material is either aluminum or copper.
Why Does Battery Cable Size Matter?
Accurate cable sizing for various electrical applications is important for various reasons. First, the cable sizing standards and regulations must adhere to the safety procedures and guidelines. Accurate battery cable sizing eliminates the risk of electrical fire accidents which can arise due to overheating, reduces the voltage drop, and much more. For optimized electrical system performance, carefully consider proper cable size and the bulk wire for a smooth flow of power. Proper cable sizing prevents any expected breakdowns in the future, thus enhancing the performance and productivity of the machine. In addition, accurate battery cable sizing minimizes worker risk, prevents electrical failure, and protects industrial investments and assets. Also, it helps to elongate the longevity of the machinery and it aids the machine systems to operate without straining.
Battery Cable Size Chart
The battery cable size chart helps you to visualize the size of the battery cables. It allows you to determine the accurate cable size for your application. Also, it indicates the type of cable you need for your system. To accurately determine the size of the cable you need to use the cable size chart.
1. Understand the DC Amp requirement. Check the current flow in ampere (Current (A)) at the top left side of the chart.
2. Determine the nature of your circuit. Then, select the accurate type of circuit from the two categories, the critical and the non-critical. These are usually used in marine and RV applications. Some of the essential circuit kinds include operational electronics, solar panel feed, and bilge blowers. Examples of non-essential circuits are used in applications such as pumps, lighting, and appliances.
3. Determine the length of the cable required. The cable must double the length of the application. For instance, if the application is 15 feet long, then, you need a 30-foot wire, i.e., 15 feet for negative and 15 feet for positive.
4. Identify the correct size of the cable. After confirming the DC ampere, intersect it to the cable length range as you identify the color code.
5. Lastly, use the cable conversion table to match the color code to the cable chart. Match the accurate circle size and specifications.
| Current(A) | 0-4 ft | 4-7 ft | 7-10 ft | 10-15 ft | 15-20 ft | 20-25 ft | 25-30 ft |
| 0-5 | 16 AWG | 16 AWG | 16 AWG | 16 AWG | 14 AWG | 12 AWG | 12 AWG |
| 5-10 | 16 AWG | 16 AWG | 14 AWG | 12 AWG | 10 AWG | 10 AWG | 10 AWG |
| 10-15 | 14 AWG | 14 AWG | 12 AWG | 10 AWG | 10 AWG | 8 AWG | 8 AWG |
| 15-20 | 14 AWG | 12 AWG | 12 AWG | 10 AWG | 8 AWG | 6 AWG | 6 AWG |
| 20-25 | 12 AWG | 10 AWG | 10 AWG | 8 AWG | 6 AWG | 6 AWG | 6 AWG |
| 25-30 | 10 AWG | 10 AWG | 10 AWG | 8 AWG | 6 AWG | 6 AWG | 4 AWG |
| 30-40 | 8 AWG | 8 AWG | 8 AWG | 6 AWG | 6 AWG | 4 AWG | 4 AWG |
| 40-50 | 8 AWG | 8 AWG | 6 AWG | 6 AWG | 4 AWG | 4 AWG | 2 AWG |
| 50-60 | 6 AWG | 6 AWG | 6 AWG | 4 AWG | 4 AWG | 2 AWG | 2 AWG |
| 60-70 | 6 AWG | 6 AWG | 4 AWG | 4 AWG | 2 AWG | 2 AWG | 1/0 AWG |
| 70-80 | 4 AWG | 4 AWG | 4 AWG | 4 AWG | 2 AWG | 2 AWG | 1/0 AWG |
| 80-90 | 4 AWG | 4 AWG | 4 AWG | 2 AWG | 2 AWG | 1/0 AWG | 1/0 AWG |
| 90-100 | 2 AWG | 2 AWG | 2 AWG | 2 AWG | 2 AWG | 1/0 AWG | 1/0 AWG |
| 100-120 | 2 AWG | 2 AWG | 2 AWG | 2 AWG | 1/0 AWG | 1/0 AWG | 2/0 AWG |
| 120-150 | 1/0 AWG | 1/0 AWG | 1/0 AWG | 1/0 AWG | 1/0 AWG | 2/0 AWG | 4/0 AWG |
| 150-200 | 2/0 AWG | 2/0 AWG | 2/0 AWG | 2/0 AWG | 2/0 AWG | 4/0 AWG | 4/0 AWG |
Wire Gauge Sizes Chart
When choosing the right wire gauge size, check on the side of the wire for a stamp or printing on the connector indicating the size. Various stranding styles indicate that one size does not necessarily fit all. It is advisable to select a bigger wire size.
The gauge of a wire refers to its girth or thickness. It is usually represented in small numbers that indicate the thicker wire gauges and large numbers to indicate the thin wire gauges.
The thickness of a cable is measured using a standard American wire gauge (AWG) ranging from 000 to 40 and it's capable of handling from 302 to 0.0137 amps respectively. The following wire gauge size chart visually demonstrates various wire sizes and thicknesses to help you easily measure wire gauge.
| Wire Gauge Size | Copper Conductor Diameter | Overall Outside Diameter with Insulation |
| 8 | 0.143-0.165 inch / 3.63-4.19 mm | 0.218-0.270 inch / 5.54-6.86 mm |
| 6 | 0.181-0.200 inch / 4.60-5.08 mm | 0.305-0.340 inch / 7.75-8.64 mm |
| 4 | 0.219-0.252 inch / 5.56-6.40 mm | 0.343-0.405 inch / 8.71-10.29 mm |
| 2 | 0.289-0.326 inch / 7.34-8.28 mm | 0.418-0.475 inch / 10.62-12.07 mm |
| 1 | 0.341-0.361 inch / 8.66-9.17 mm | 0.479-0.520 inch / 12.17-13.21 mm |
| 1/0(0) | 0.348-0.405 inch / 8.84-10.29 mm | 0.500-0.565 inch / 12.07-14.35 mm |
| 2/0(00) | 0.429-0.460 inch / 10.90-11.68 mm | 0.568-0.655 inch / 14.43-16.64 mm |
| 3/0(000) | 0.485-0.510 inch / 12.32-12.95 mm | 0.641-0.670 inch / 16.28-17.02 mm |
| 4/0(0000) | 0.555-0.580 inch / 14.10-14.73 mm | 0.695-0.741 inch / 17.65-18.82 mm |
Battery Cable Amperage Capacity Chart
The amperage unit measures the amount of current an appliance requires to operate when connected to the battery. For instance, an inverter will use around 150 amps while a light bulb only utilizes 10 amps. To calculate the amperage, you must understand the total current drawn by the appliance. Additionally, you can establish the amperage of your appliance by dividing its wattage by voltage. The voltage allows the electrons to transfer to the positive side from the negative side.
The role of a battery cable amperage capacity chart is to help you determine the accurate battery cable size. It guides you to calculate the amperage of the device using its wattage, then guides you to match the size of the cable based on the voltage of the appliance.
The following amperage cable chart demonstrates the cable size and the amperage.
| Battery Cable Size | 50 Amps | 100 Amps | 150 Amps | 200 Amps | 300 Amps |
| 6 AWG | 11.8 ft | 5.9 ft | 4.4 ft | 2.9 ft | 2.2 ft |
| 4 AWG | 18.8 ft | 9.4 ft | 6.3 ft | 4.7 ft | 3.1 ft |
| 2 AWG | 29.8 ft | 14.9 ft | 9.9 ft | 7.4 ft | 4.9 ft |
| 1 AWG | 37.7 ft | 18.9 ft | 12.6 ft | 9.4 ft | 6.3 ft |
| 1/0 AWG | 47.5 ft | 23.8 ft | 15.9 ft | 11.9 ft | 7.9 ft |
| 2/0 AWG | 60 ft | 30 ft | 20 ft | 15 ft | 10 ft |
| 3/0 AWG | 75.6 ft | 37.8 ft | 25.2 ft | 18.9 ft | 12.6 ft |
Common Mistakes to Avoid When Choosing Battery
Common mistakes people make when choosing the battery cable can lead to underperformance, damage, and fire incidents. Some of the common mistakes you must avoid when choosing a battery cable are:
1. Picking the Wrong Cable Gauge
The right cable gauge is necessary for ensuring efficient power transmission and it also prevents voltage drop. Before you choose the cable gauge, check the current requirements of the battery and the cable length. A bigger gauge cable is suitable for short cable length and low current. A smaller gauge is suitable for a longer cable length and high current needs. Use the cable gauge chart to choose the right cable gauge for your application.
2. Choosing the Wrong Cable Length
Another common mistake you are likely to make when choosing the right battery cable is ignoring the length requirements. The length of the cable determined its performance. A longer cable introduces resistance which leads to power loss and voltage drop. When choosing the cable, measure the distance between the battery and the appliance or device. It will enable you to choose the right size cable.
3. Choosing the Wrong Connector Type
The wrong connector type or a mismatched connector leads to poor connection and it may result in battery or device damage. The connector is the interface between the battery and the appliance. Therefore, you must ensure a secure connection and compatibility. When choosing the right connector, consider factors such as the battery type, the machine you are powering, or the application. Choose a connector that matches both connectors, on the battery and on the device to ensure proper fitting and secure connection.
Final Thoughts
The role of the battery cable size chart, the battery cable amperage capacity chart, and the wire gauge sizes chart are to help you understand the battery cable measurements, performance, and sizing. Choosing the right battery cable ensures the reduction of voltage drop, and overheating, and enhances the performance of the electrical system. Renogy batteries are compatible with the Renogy battery cables which prevents problems such as voltage drop, underperformance, and overheating. In addition, the Renogy battery cables have optimum thickness and length for safe use on your appliances.
FAQs About Battery Cable Size Chart
1. Can I use a smaller gauge cable for short distances?
You can use a smaller gauge cable for a short distance. That’s because a shorter distance reduces the impact and increases the resistance from smaller wire sizes, which is normally the major concern when using small gauge cable.
2. What happens if I oversize the cable?
If the battery cable wire is too long, it causes higher resistance, resulting in a voltage drop. If the battery cable is too short, it might result in overheating, thus a fire risk.
3. Do I need different cable sizes for parallel Vs. series connections?
If you are doing parallel connections, you need a larger cable. However, if you installing series connections, you require a smaller cable for a similar power load.
