Advice about buying a charging cable

One often overlooked item when buying an EV charger is the charging cable itself.

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Does it really matter what cable you buy? Yes! Without the correct cable, both home and on-the-road EV charging will be slower and more frustrating than necessary.

Here's what you need to know:

1. Tethered or untethered charger?
2. How long should the cable be?
3. Are coiled cables a good idea?
4. What connector types should be on each end?
5. Should you get a three-phase or single-phase charging cable?
6. What cable rating (amps) do you need?
7. Why you can’t daisy-chain charging cables.
8. Do you need your own cable for public charging?
9. Certifications and standards.
10. Looking after your cable.

Who would have thought there would be so much to consider?

Note: From here on, I’ll also refer to EV chargers as EVSE (Electric Vehicle Supply Equipment) because, technically, the EV charger is inside your car, and the box on the wall simply delivers AC power.

#1 Tethered Or Untethered?

As far as cables go, EVSEs come in two types: tethered and untethered.

Untethered

Untethered chargers come without a charging cable and allow you to connect your own.

Untethered Chargers: Pros and Cons

• Pro: Flexibility. Use any length of charging cable you prefer. You can customize cable lengths, eliminating the need to shuffle cars around to get close to the charger. You can change the length if needed.
• Con: Additional cable management. Bring your own cable, plug and unplug both ends, unroll and roll up the cable, carry, and store it separately. You will need your own storage setup, as it is not integrated into the EVSE.
• Con: Extra cost. The cable doesn’t come with an untethered EVSE, so you’ll need to purchase one in addition to the charger. Untethered EVSEs are typically $20-50 cheaper than tethered ones, but a cable costs $100-$200.
• Con: Theft concerns. If your EVSE does not lock the cable when you are not charging, you must either put it away after every charge or risk theft.
• Pro: Theft prevention. If you worry about theft, you can store your cable away when it’s not in use.

Tethered

Tethered chargers have a fixed-length cable permanently attached:

Tethered Pros and Cons

• Pro: Convenience. The cable is permanently fixed to the EVSE, so there’s only one end to plug in (your vehicle). Just plug it in and start charging, then hang it back on the charger.
• Con: Limited flexibility. Since the cable length is fixed, it may not work for multiple EVs or different parking scenarios.
• Con: Maintenance. If the cable gets damaged and requires replacement, you may incur service call charges and waiting time.

#2 How Long Should Your EV Charging Cable Be?

Charging at home

First and foremost, you want a cable long enough to charge at home conveniently. Measuring the distance from the EVSE to the charge port on your vehicle is a good place to start.

Did you know there’s no standard for charge port locations across the various EV models in Australia? A family member may upgrade their vehicle, so it’s wise to have a cable that can reach any car, regardless of whether it’s forward or reverse parked.

Multi-Car Families

Most households in Australia have more than two cars. A longer cable saves the hassle of moving cars around if your cable can reach the charge port, regardless of its location on the driveway.

What Are The Available Cable Lengths?

Tethered chargers typically have cables ranging from 5m to 8m. Untethered EVSEs can have cables from 5m to about 10m or longer if you look for them. The SolarQuotes EV Charger Comparison Table lists the various cable lengths for recommended EVSE sold in Australia. A deeper investigation in the data sheet for each charger will indicate whether it’s tethered or untethered (this information will also be added to the table soon).

My recommendation: Get an untethered charger and a long charging cable. If you choose a tethered charger, avoid the 5m version and opt for 7m or longer.

#3 Are Coiled Cables A Good Idea?

With a tethered EVSE, you get the cable that comes with it, which is usually a straight cable. For untethered, you can choose between straight or coiled. The choice is personal. Below are the pros and cons of coiled cables:

Coiled Pros

• Space Efficiency: Coiled cables require less space for storage, making them convenient for compact storage in vehicles or charging stations.
• Easy Handling: The coiled design allows for easy extension and retraction, providing a tangle-free charging experience.
• Flexibility: Coiled cables stretch and retract to accommodate varying distances between the charging station and the vehicle.
• Trip Prevention: The coiled shape prevents tripping hazards by keeping the cable compact and off the ground.

Coiled Cons

• Less Length: Coiled cables may have a shorter effective length than their straight counterparts when fully extended, limiting charging range.
• Tension and Strain: The coiled design can create tension on the cable, leading to wear and tear over time.
• Limited Flexibility: Coiled cables offer flexibility within their extended range but may lack the maneuverability of straight cables.

#4 What Connector Types Should Be On Each End?

Fortunately, all EVs sold in Australia since now have a standardized socket that fits a Type-2 or Mennekes connector.

Most EVs also have a second socket below the Type 2 connector. This configuration is called CCS (Combined Charging System). When purchasing cables, you only need a Type-2 connector on the car end and a Type-2 socket on the EVSE end. However, I recommend double-checking your vehicle, as some older EVs may use different connectors.

#5 Should You Get A Three-Phase Or Single-Phase Charging Cable?

Single-phase and three-phase

In Australia, Type-2 plugs and sockets are compatible with both single-phase and three-phase charging cables.

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A single-phase charging setup, typically for residential charging, uses only a subset of pins to provide power. In contrast, a three-phase charging setup commonly found at commercial or public stations uses all pins to enable higher power and faster charging rates.

Upon plugging in the cable, the onboard EV charger will automatically detect the available power supply and adjust the charging process accordingly.

Charging Rates (kW)

Depending on your car's maximum charge limit, a single-phase, level-2 EVSE can charge up to about 7kW (32 amps), while three-phase can reach up to 22kW.

Even if you only have single-phase supply at home, a single-phase charging cable will charge much slower when using AC public three-phase chargers, so consider this when purchasing a cable. You can still use a three-phase charging cable on a single-phase charger at home (it will charge from single-phase, though).

#6 What Cable Rating (Amps) Do You Need?

Standard ratings for EV charging cables sold in Australia are:

• Single-phase: 3.6kW (16 amps)
• Single-phase: 7kW (32 amps)
• Three-phase: 11kW (16 amps per phase)
• Three-phase: 22kW (32 amps per phase)

Your charging cable must handle the maximum charge rate of your vehicle, which is often lower than what the EVSE can supply. It's also strongly recommended that the cable is rated for the full output of the EVSE.

Voltage Drop

Due to a phenomenon known as voltage drop, opting for a thicker cable (32 amps rather than 16 amps) is recommended. A thinner and longer cable can create increased resistance, resulting in less voltage at the end of the cable compared to the beginning, causing less power to reach your car battery. Voltage drop is more significant as the current is increased. For level-2 EVSE, it’s better to choose 32 amp cables for faster charging.

My recommendation: Even if your home charger is single-phase, buy a 22kW (32A) three-phase cable. It is only about $30 more than a single-phase cable and will allow you to maximize the charging speed at three-phase Level 2 public chargers.

#7 Why You Can't Daisy-Chain Charging Cables

If you buy an EVSE with a short 5m cable, you'll soon realize it's frustratingly short.

You might think that daisy-chaining a third-party charging cable will solve your problem. After all, the socket on that cable will fit into the tethered plug.

However, it won’t work.

There are some hacks to make it work, but don't do it. The Type-2 connectors are engineered so that a plug from one cable cannot fit into the socket of another cable completely, preventing it from powering up. This is a safety feature designed to avoid such scenarios! Given the high charging currents and potentially lethal voltages involved, this design serves an important purpose.

#8 Do You Need Your Own Cable For Public Charging?

Yes and no. Public charging stations primarily come in two types: DC level 3 fast chargers and AC level 2 destination chargers.

The DC fast chargers come with cables attached and can charge at very high rates of up to 350kW directly into the battery. You can think of these as similar to a petrol bowser with an attached hose for fueling internal combustion engine (ICE) vehicles.

Conversely, AC destination chargers, which are much more common, may or may not have a cable tethered to the charger. I would argue that carrying your own cable is essential in Australia.

Tip: If you have an untethered charger at home and store your charging cable in your car, you can also use it at public charging stations.

#9 Certifications and Standards

All electrical equipment imported and sold in Australia must comply with AS/NZS standards and other applicable guidelines. Purchase online from overseas at your own risk.

#10 Looking After Your Cable

It’s not rocket science; all the usual care guidelines apply.

Keep it clean and dry, avoid bending or kinking it, don’t wrap it too tightly, don't drive over it, don’t drop it, use the dust caps, treat it with respect, and occasionally check for abrasions or damage.

Winding Up

In the world of EV charging cables, size does matter. The most essential thing is to get a long and robust cable: at least 7m and 32A, three-phase. Your EV will be grateful.

Hopefully, I’ve cleared up some confusion and provided you with helpful hints for finding the perfect cable. That’s about all I have to say, and now I must go before I run out of puns and innuendos. I’m sure you’ll let me know if I’ve missed anything.

Additionally, you might want to check out this EV Charging 101 guide if you haven’t done so already. Happy charging!

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