What Gauge Extension Cord For Battery Charger?

Did you ever wonder which gauge extension you should use for a battery charger? Well, you are not alone in this, many people have the same concern too. Different chargers need different types of gauges, using the wrong one can damage your battery.

So, the question is what gauge extension cord for battery charger?

You can use 10-gauge, 12-gauge, 14-gauge, or 16-gauge extensions for your battery charger. The 12 and 14-gauge extension cords are ideal for most households. However, you can use 16-gauge extensions for low amperage and 10-gauge for power-hungry devices. They come in 25, 50, and 100 feet lengths.

In this article, I’ll discuss the gauge extension cord for all types of battery chargers. I’ll also discuss precautions so let’s hop into the business, shall we?

Does Gauge Matter for The Extension Cord?

Does Gauge Matter for The Extension Cord

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Gauges play an important role in extension cords. The incorrect gauge extension cord can damage your battery beyond repair and even cause a fire.

By now, you already know that gauges have different amperes depending on the device’s power consumption. However, a good gauge extension matters. 

We all know some basic science about electricity. The higher the resistance the lesser the current flow. So, if the cord you’re using has high resistance the current will not pass smoothly through the cord.

Now, you may ask, how to know if your cord has high resistance or not? The resistance of a cord depends on two primary factors:

  1. The length of the cord.
  2. The diameter of the cord.

Remember? We previously mentioned that the cords’ ampere ranges depend on the length. The longer the cord the higher the chance of resistance. 

That’s why choosing the right extension cord is necessary. T thicker extension cords perform better compared to thick cords. It’s because it has a bigger diameter which allows electron particles to move around freely. 

On the other hand, a thin cord doesn’t have enough room for the electron to move freely. Hence. It produces more resistance resulting in voltage drops at long distances.

Now, let’s move on to the different types of battery chargers vs their ampere ranges.

Gauge Extension Cord For 5 Types Of Battery Chargers

Gauge Extension Cord For 5 Types Of Battery Chargers

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We have gathered five types of battery chargers, their amp ranges, and the extension cord gauge. However, there are multiple factors and variations for each of the batteries. For now, let’s have a quick overview of the battery chargers.

Types of Battery ChargerBattery Amp RangeCord LengthExtension cord Gauge 
Car battery charger10-25 Amps25 ft-100 ft12-Gauge
Boat battery charger15-20 Amps25 ft-100 ft10-Gauge
Motorcycle battery charger3 Amps (Max)25 ft-100 ft16-Gauge AWG
Electric lawn Mower battery charger10-12 Amps25 ft-100 ft12-Gauge
Golf Cart Charger5-18 Amps25 ft-100 ft10 AWG/12-Gauge

From the table we see, battery chargers for different devices need different gauge extension cords. However, 12-gauges are the most common ones. It’s because the 12 gauge extension cord is the allrounder. It can tolerate up to 15-18 amps.

Now, let’s explore all the types of battery chargers in detail.

What Gauge Extension Cord For Car Battery Charger?

12-gauges are the ideal gauge extension for car battery chargers. However, there are different factors to keep in mind. Batteries can have different amp hours for the same voltage. So, you need to determine which gauge wire to connect 12V batteries.

For example, a 12 volt can have 10,20,30,100,200 or 5000 ampere hours. Depending on the ampere-hours, the wattage will vary. So, you need to know your battery’s amp hours to determine the suitable gauge extension.

But before we get into the data, we have to understand the relationship between a volt, amp hour, and wattage. Don’t panic! It’s quite easy if you ask me.

Let me explain, have you ever noticed the stickers in the batteries? They’re weird right? But they bear a lot of information. The stickers contain the battery’s Cold Cranking amps (CCA), Reserve Capacity (RC), Amp Hours (AH), Deep Cycle, etc. 

We will tell you more about how to select the right gauge or your device in the later part of this article. For now, continue reading and we will unravel the mystery together.

Now, let’s look into the car battery charger amp ranges and the recommended gauge extension cords. Usually cars have 12 volt  Follow the table below.

From the table, you can see that the cord length affects the ampere ranges. So, you should choose the suitable extension cord keeping the distance in mind.

What Gauge Extension Cord For Boat Battery Charger?

Now coming to the boat battery charger. We have mentioned earlier that a boat battery charger typically ranges between 15-20 Amps. That means it needs a 10 gauge heavy-duty extension cord for such a power load. Now, check the table below.

Note: There are two types of 10-gauge extension cords. One is a normal U-Ground gauge for a maximum of 15 amps. Another one is a Twist lock that can tolerate up to 20 amps. We will be showing both the gauges and their amperage differences.

The table shows no matter distance, you’ll get the same amperage with a 10-gauge twist lock cord. Now, let’s check out the U-Ground one.

So, with a U-Ground 10-gauge, you’ll get 15 amps no matter if the distance is 25,50, or 100 feet. Also, you will get durability both indoors and outdoors.

What Gauge Extension Cord For A Motorcycle Battery Charger

For a motorcycle battery charger, experts say the charger amp should not exceed three amps. Anything greater than that will damage the internals of the battery. In the worst cases, it can heat up and cause a fire.

So, you’ll need a 16-gauge AWG extension cord for your motorcycle battery. Note that distance is the factor here. You can see from the table, at 100 feet the amperage changes so you have to adjust accordingly.

Pro tip: To determine the suitable gauge extension cord for your bike’s 12V battery calculate the amps. Know how many amps there are in a battery of 12 volt.

What Gauge Extension Cord For An Electric Lawn Mower

The average amperage for a battery lawn mower is 10 Amps. For 10 Amps current flow, you will need a 12-gauge or 14-gauge extension cord for smoother operation. Since we have already discussed 12 gauge, let’s have a look at the 14-gauge cord.

The table shows, 14-gauge extension cord can serve well even at 100 feet distance. So, both 12 and14-gauge would be ideal in this particular case. It’s your call! 

What Gauge Extension Cord For Golf Cart Charger?

Now, coming to the golf cart charger. We found that golf cart battery chargers have different variations and amp ranges. The average amp range for the golf cart chargers is 5 to 18 amps. Hence, the ideal gauge extension cord would be the 12-gauge. 

As we’ve seen earlier, a 12 gauge cord can maintain 15 amps up to 100 feet. The good news is, it can easily tolerate up to 18 amps. No wonder why it’s considered an all-rounder. So, for your golf cart battery charger, you can entirely rely on a 12 gauge.

How to Select The Right Gauge Extension Cord For Battery Charger?

I have discussed different extension cords for different types of battery chargers. Now, you might be wondering, how to select the right gauge for your battery charger.

Remember I told you I got a mystery to unravel? Yeah right, let me explain it to you.

To determine the right gauge extension for your devices, follow these 3 simple steps.

Step 1: Calculate Total Watts

First, calculate the total watt of all of your devices. Let’s see how to do that.

To calculate the wattage, we have to consider just one factor, ampere-hours (AH). It refers to how many amperes a can battery can deliver within one hour. If you multiply the amp hours by the current voltage of the battery, you’ll get the wattage.

For instance, the average car battery has a 12-volt battery, but the ampere-hours may differ depending on the battery model. So, the calculation would be,

Wattage = Total Amp Hour (AH) x 12V.

So, for a 200 AH 12V battery, the wattage would be 200×12 = 2400 Watts.

Step 2: Divide with the Standard Household Voltage

The standard household voltage is 110. Now, divide the total watts by 110.

Step 3: Round up the Value

What you get from the division, just round it up to the nearest whole number to know the gauge extension cord. For instance, if your device has a total of 1600 watts, the calculation would be,

Total Wattage = 1600 watt / 110  = 14.5 = 14 (Rounded)

So, you will need a 14 gauge extension cord for your devices. Easy peasy! Now you might be thinking, how to tell what gauge your extension cord is?

There are primarily three ways to tell what gauge extension you got. These are

  • Read the packaging label or find it printed in the cord. If it says 12/3 that means you got a 12-gauge cord. If it says 16 AWG that means you got a 16-gauge cord.

Pro tip: If you don’t find any printed gauge numbers in the cable or the label, it’s maybe a low-quality one. I recommend against using those low-quality ones since they can cause unexpected consequences.

  • Check the thickness of the cord, the thicker cord the higher gauge. However, in this way you cannot be 100% sure about the gauge. To determine the exact gauge, check the diameter of the cord by cutting it open. 

To measure the diameter of the cord you’ll need a tool called a caliper. Check the below table, the diameters for the cords are given.

AWG GaugesDiameter (Inch)Diameter (mm)
10 Gauge0.10192.5882
12 Gauge0.08082.0523
14 Gauge0.06411.6281
16 gauge0.05081.2903

From the table above, you can determine which gauge extension cord you got. Good luck with that. 

3 Different Types of Extension Cords And Their Gauge

3 Different Types of Extension Cords And Their Gauge

Image Source: Ohio Power Tool

There are different gauge extension cords available to choose from. You might get confused about which one to choose for your device. 

The gauge extension cords are primarily divided into three categories: Indoor, outdoor, and expert/heavy duty. Let’s explore all of them.

Indoor Gauge

16-gauge is considered an Indoor gauge for medium-duty usage. It has an amperage range from 10-13 amps. This gauge is used for medium-duty devices that consume lower-mid levels of electricity. 

If your battery has the same amount of ampere requirement, you can safely use a 16-gauge extension cord. Also, you can use it with any medium-duty electronic devices like TV, computer, printer, scanner, lamps, etc.

Outdoor Gauge

The 14-gauge extension cord is considered the outdoor heavy-duty gauge. When we say outdoor we strictly mean outdoor. This gauge is not recommended to use in household devices. So you have been warned! 

Since this cord is specially made for outdoor environments, it is ultra-durable. It’s immune to rough temperatures so you can rely on whatever the weather is.

The 14-gauge extension cord has an ampere range of 13-15 amps depending on the cord length. Don’t bother, I will talk more about the cord lengths in the later part of this article. So, let’s stick to the category of gauges from now on.

Heavy Duty Gauge

The last one we have is the 10-gauge heavy-duty cord for power-hungry devices. It is ultra-durable to pass through high voltage currents without any voltage drop. It can work both indoors and outdoors without affecting performance of any kind. 

It has a thicker insulation feature to fit in a rough outdoor environment. At the same time, it has multiple outlets to fit in your indoor settings whenever you need it. 

Now, let’s move on to the next important subject to discuss. The importance of the gauges, should you care about the gauges? Do they really matter? 

What If You Choose the Wrong Gauge Extension Cord? 

Using the wrong gauge extension cord has several results. These are

Result 1: Damaged Device

It’s important to know about your device’s required volt, amp, and watt. If the gauge you’re using doesn’t match with the manufacturer’s required values, it will malfunction.

Some gauge has limited tolerance to high amperes. If the device needs a high surge of current flow, it will end up melting the cords. So, be sure to check the device’s requirements to select the suitable gauge extension cord.

Result 2: Overheating and Catching Fire

If the gauge can’t tolerate the current flow it will overheat and melt. Sometimes even worse, it can cause fire when dealt with high voltage. Always check the wattage/voltage of your device to select the suitable gauge for such power.

We’ve discussed earlier that 12-gauges are suitable for most households. Also, It can tolerate up to 18 amperages when needed. If the combined wattage of all your devices is higher, consider having a heavy-duty 10-gauge.

Result 3: Risks of Injury

If you have kids or pets in your house, be extra careful while choosing gauge extensions. Make sure you don’t mix up indoor and outdoor gauges. You should never use outdoor gauges in the indoor environment and vice versa. 

Indoor gauges aren’t made for outdoor environments, they’re not durable in rough weather. If you use an indoor gauge outdoors it can cause a short circuit. So you have to make sure you are using the gauge produced for outdoor use.


Can You Use an Extension Cord With an EV Charger?

You can definitely use an extension cord with any electric vehicle. Make sure you know the battery amps of your electric car. Choosing the wrong can damage the battery of your car. The ideal extension gauge for electric cars is the 10-gauge AWG. 

What Gauge Extension Cord For Schumacher Battery Charger?

For a Schumacher battery charger, you will need a 25 ft 18-gauge extension cord. The 18-gauge AWG has an amp range of 10 amps/125 volts. The Schumacher battery charger has an amperage of 15 amps followed by a 3 amp maintainer. Hence, an 18-gauge AWG extension cord is ideal for this battery charger.

Is 10 Gauge Better Than 12 Gauge Extension Cord?

For most household needs, a 12-gauge extension cord is ideal. However, devices like air conditioner, oven, etc. will need a 10-gauge extension for optimal current flow. So, I can’t say 10 gauge is better than 12 or vice versa. Both of the cords are made for different power loads and devices.

Do Extension Cords Charge Slower?

Ideally, the extension cords don’t cause a slower charge. However, depending on the manufacturer the quality of the extension cord can differ. High quality cords have lesser resistance for smoother current flow. But low-quality cords can have high resistance and voltage drop compared to the good ones.


In this article I have discussed your query on, what gauge extension cord for battery charger? These are 10 gauge, 12 gauge, 14 gauge, and 16 gauge. Different battery chargers need different gauge extension cords depending on the amperage. 

I also demonstrated which gauge you should select for all of your different devices. Furthermore, I discussed the consequences of using the wrong cords and how to choose the right gauge. 

I think I’ve provided all the answers to your query. Good luck with the gauge extension cords. Until next time!

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