How long can an EV charging cable be
Electric Car Charging

Do longer charging cables take longer to charge?

Long electric car charging cables mean more convenience. You can charge your EV in your house or at public charging stations without worrying about the distance between your car and the charging point. So, how long can an EV charging cable be? Is a long charging cable always suitable?

As an EV owner, you might have a lot of questions when it comes to buying an EV charging cable. Keep reading to find answers for all of them.

How Long Can an EV Charging Cable Be?

There is no limit to how long a charging cable can be. It can be as long as possible. According to the National Electric Code (Section 25), 25 feet is the longest EV cable that electric vehicle sellers can provide. However, the National Electric Code only applies in the US. Outside the States, the length of EV cables can go as high as 20 metres.

A long charger cable is beneficial, as you can park your EV away from the charging point and still charge it. A long tethered cable can help you save on installation costs, as you can install the EV charging station closer to the service panel. Overall, a long extension cable means more operational flexibility.

Ideal Length of Electric Car Charging Cables

Choosing an appropriate length of charging cable is essential. There are no standard guidelines around the best size of EV cables, but the recommended length is between 4m and 10m. That said, you can go for longer cables depending on your requirements.

For example, if the distance between your EV and charging station is small, a short EV cable will get the job done. If you need a cable that stretches around your house to reach your EV, longer cables measuring 15m or 20m will be the ideal pick.

Please note that length is not the only criteria to consider when selecting an EV cable. Several other factors must also be considered before making the final decision. You can follow this ultimate guide to buying charging cables for electric vehicles.

How Does Length Affect Charging Performance?

As humans, we need speed, convenience, comfort, and performance all at once. You might want a cable that charges your EV over a long distance in less time. Sadly, it isn’t possible. Science comes into the picture.

The length of a cable affects the charging speed, according to physics. It applies to all cables, including EV cables, USB cables, laptop chargers, etc. There’s a clear relationship between charger length and charging speed. If two cables of equal thickness and made of the same materials have different lengths, the shorter cable will charge faster than the longer cable.

The formula of resistivity explains this effect:

Resistivity: Length / Cross-Sectional Area

When electricity flows through wires, it experiences some resistance (opposition to the flow of electric current). The higher the resistance, the lower the flow of current, resulting in a lower charging speed.

The above formula states that resistance (or resistivity) is directly proportional to the length and inversely proportional to the cross-sectional area of the cable. Thus, a long and thin cable will have high resistance and take longer to charge than a short and thick cable.

A member of the XDA Developers forum performed an experiment to prove the relationship between cable length and charging speed. They took three cables of sizes 12″, 36″, and 72″. The experiment concluded that the 12″ cable charged 1.3x faster than the 36″ cable, while the 36″ cable charged 1.7x faster than the 72″ cable. On average, there was a 1.5x reduction in charging speed when the length of the cable was doubled. The output was the same for each cable.

Therefore, it’s established that long charging cables take longer to charge than short charging cables. If you plan to get a long EV cable, your electric car will take a few extra minutes to charge.

Can You Extend an EV Charging Cable?

What if you have already bought a fast charging cable? EV cables are expensive, and buying a new cable just because the previous one is short may not be the best decision. The good news is that you can extend your EV cable using an additional charging cable.

Extension cords come in various lengths and specifications, and you can choose the one that best fits your needs. You can extend all EV cables, including three-pin and tethered cables.

Another concern for EV owners is whether an extension cord reduces charging speed. The answer is no. The final charge speed will be the same as your initial charge speed. So, if your charger has a 7.2 kW output, it will remain the same.

However, you must ensure that the additional cable has a power rating equal to or more than your primary connector. If you use a charger with a lower power rating, the overall charging speed may decrease.

You can follow this guide to extending your EV charging cable for more information.

 

Benefits and Drawbacks of Long EV Charging Cables

Long charging cables have upsides and downsides. You’ll need to balance them based on your needs and make the right choice. Let’s look at the pros and cons of long charging cables.

Benefits:

  • Long cables are convenient. You can park your car far away from the charging station and still charge it comfortably. Thus, long cables are ideal for outdoor use, especially if you charge your vehicle in public areas.

Disadvantages:

  • Long cables take longer to charge. If you prefer quick charging, long cables may not be the right pick for you.
  • Long cables are difficult to maintain. They are heavy, and therefore, challenging to carry and store. Since they’re long, they are more likely to tangle, giving you a hard time.

 

Other Factors Affecting the Charging Speed of an EV Cable

While the length plays a vital role in the charging speed of an EV cable, it isn’t the only factor. Several other factors collectively act to determine the power output, and thus, the charging speed. Let’s briefly discuss some other factors that influence the charging speed of electric cars.

Type of Charger

The type of charger is inarguably the most crucial factor that influences charging speed. Electric vehicle chargers are broadly classified into two types: AC charging cables and DC charging cables.

AC chargers come in two types: type 1 and type 2. Type 1 chargers are single-phase only and have a power rating of 3.7-7 kW. They can add 12.5-25 miles per hour. In contrast, Type 2 chargers support three-phase power and have a power rating of up to 22 kW. They can add up to 75 miles per hour. Some three-phase cable chargers support over 40 kW power rating, giving over 100 miles of charge per hour.

The second type of charger is DC chargers or rapid chargers. They are faster than AC chargers. They come in two types. The first is CHAdeMo, which has a 50-100 kW power rating and can add 75-150 miles per hour. The second is CCS, which has a power rating of up to 350 kW and can add up to 525 miles per hour.

Therefore, if you have an extremely long CCS charger, it may still charge faster than an extremely short Type 1 AC charger.

Max. Charge Rate of the Vehicle and Connectors

If your car supports 7 kW charging only, it won’t charge any faster than 7 kW even if you use 22 kW adapters. The cable length might end up being pointless if your EV has a low charge rate.

Battery Size and Fullness

The larger the battery, the longer it will take to charge. An electric car with a 60 kW battery will take more time to charge than a car with a 40 kW battery, provided that you use the same charger. Also, if your battery is nearly full, it will fully charge in less time than an almost empty battery.

Environmental Factors

Environmental factors also affect charging speed. An EV takes slightly longer to charge in colder climates compared to hotter regions. This effect is more noticeable when you use public charging stations with rapid chargers.

 

Conclusion

Length is an essential factor to consider before buying an electric car charging cable. A longer cable provides comfort, convenience, and easy charging. However, you might end up losing some charging speed. Longer cables take more time to charge, and that is an adjustment you will need to make if you choose a longer cable.

 

Frequently Asked Questions

How long can an EV charging cable be?

There is no hard-and-fast rule for choosing the length of charging cables. They can be as long as someone wants. However, the longest EV charging cable available in the UK is 20 metres. In the US, the maximum allowed length for EV cables is 25 ft.

Do longer charging cables take longer to charge?

Yes, longer charging cables take longer to charge. The longer the charging cable, the higher the electrical resistance, which means slower charging. Therefore, if you prefer fast charging, it’ll be better to opt for shorter charging cables. Additionally, thicker charging cables charge faster.

What is the longest Tesla charging cable?

The longest Tesla charging cable is the Tesla wall connector. It is 24 ft. (7.3 m) long. The length makes it ideal for both indoor and outdoor settings. The cable can add up to 44 miles of range in an hour and is suitable for houses, apartments, and commercial buildings.

About EV Cable Shop

Debbie has been working in the EV industry for over 7 years and has always had a keen interest in both advancing technology and sustainability. She is an expert in the field and is always up to date with the latest releases and news.

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