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What Gauge Extension Cord for Battery Charger? – Answered

Written by Edwin Jones / Fact checked by Andrew Wright

what gauge extension cord for battery charger

When charging any batteries, it is critical to utilize the correct size extension for safe and effective charging. If you wonder what gauge extension cord for battery chargers is needed, here is the answer.

It is only advisable only to use heavy-duty extension cords to charge a car battery. These are the cords that usually come in a larger gauge.

In most cases, a 12-gauge cord with a rating above 13A will do, but you must also take into account its length and the specific type of battery charger.

Below will provide a solid understanding of why this is the best-advised option, including some tips for selecting extension cords.

What Size of Extension Cord for Battery Chargers?


When utilizing an extension cord to charge batteries, understand that you might require a different size of extension cord wire gauge depending on the battery charger type. This is because various batteries have a capacity rating requiring different charge rates.

Furthermore, the application length is also important, as a longer cord means higher resistance, resulting in a voltage drop. In this case, you might require a larger cord for a lengthy application.

For example, the result may be different if you wire an extension cord to a car battery charger that comes in various lengths. Charging a battery using longer cords might take longer, especially if it reaches more than 100 ft.

On average, a heavy-duty 50 ft 12 gauge is best recommended for most battery chargers. However, the chart below may be a good reference to give you an idea of what size extension cord is recommended for each battery charger type.

Depending on the Types of Battery Chargers

Types of Charger Battery Amperage Rating Length of Application Recommended Extension Cord Size
Car Battery Charger 25 amps Under 100 ft. 12 gauge
Boat Battery Charger 20 amps Under 100 ft. 10 gauge
Electric Vehicle Charger 16 amps Under 100 ft. 12 or 10 gauge
Phone Charger 2 amps Under 100 ft. 14 gauge
Power Tools Fast Charger 12 amps Under 100 ft. 14 or 12 gauge

12 Or 14 Gauge


When comparing a 12 gauge vs 14 gauge extension cord, the type of charger for each application should be considered. A 14 gauge extension cord has a thinner wire that is best for low ampacity chargers under 15 amps.

A 12 gauge, on the other hand, has a larger diameter that can handle higher loads up to 20 amps for 50 ft. length. This cord is ideal for chargers that usually provide high charging rates, such as car batteries. This can also be used for boat battery charger, but when it comes to charging efficiently, I would recommend a 10 gauge cord.

Tips to Choose the Right Extension Cord for Battery Chargers


Choosing an extension cord for a battery charger may cause a bit of confusion. However, to help you find the right size extension cords that suit your needs, here are some tips you can follow.

  • If you must pick between a short 12 gauge extension cord and a longer one, always go for the former option. This is because shorter cords typically can handle higher loads than longer ones with the same gauge.
  • When buying a heavy-duty 12 gauge charger extension cord, check if it’s suitable for the specific weather condition in your a This is especially true for places with cold climates, which call for frost-tolerant cord materials.
  • Choose the one with a durable and flexible cord, as it is easier to use, especially in some workplaces with many obstacles or tight spaces.
  • Pick a cord with a locking feature to ensure that your connection will not become loose.

Frequently Asked Questions


How Many Amps can a 12-Gauge Extension Cord Handle?

A 12 gauge extension cord can handle different current ratings depending on its length. For a 12 gauge extension cord 10 ft to 50 ft, it can handle 20 amps of current. At the same time, a 100 ft. application can hold up to 15 amps of current.

Best Type and Size of Extension Cord for Battery Charger

The best type of extension cord for car battery chargers or any other type is only the heavy-duty ones. These mainly come in a larger size, enough to handle a higher load of current that a battery charger may require.

Typically, a 12-gauge cord will suffice. However, if the cord is particularly long and must handle at least 15 amps, you should upgrade it to a 1o-gauge one.

Can You Use a 16 Gauge Extension Cord for a Battery Charger?

A 16 gauge cord is only recommended to use for a low amp battery charger, such as one for a motorcycle. Using the 16-gauge extension cord for higher amp chargers may cause it to heat up and damage the cord’s insulation, resulting in potential hazards.


Reading this entire article will give you an idea of what gauge extension cord for battery chargers to have an efficient charging system. Moreover, following the guides above when choosing the best extension will also help you prevent electrical hazards.

However, most experts advise against charging a battery using an extension cord since it may catch fire if it breaks. In this scenario, it is best to charge your battery directly on a wall outlet or consult the charger’s manual to see if the manufacturer allows it to be used with extension cords.

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