EV Charging Connectors Come In Many Shapes and Sizes [Hackaday]

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Electric vehicles are now commonplace on our roads, and charging infrastructure is being built out across the world to serve them. It’s the electric equivalent of the gas station, and soon enough, they’re going to be everywhere.

However, it raises an interesting problem. Gas pumps simply pour a liquid into a hole, and have been largely standardized for quite some time. That’s not quite the case in the world of EV chargers, so let’s dive in and check out the current state of play.

AC, DC, Fast, or Slow?

Since becoming more mainstream over the past decade or so, EV technology has undergone rapid development. With most EVs still somewhat limited in range, automakers have developed ever-faster charging vehicles over the years to improve practicality. This has come through improvements to batteries, controller hardware, and software. Charging tech has evolved to the point where the latest EVs can now add hundreds of miles of range in under 20 minutes.

However, charging EVs at this pace requires huge amounts of power. Thus, automakers and industry groups have worked to develop new charging standards that can deliver high current to top vehicle batteries off as quickly as possible.

As a guide, a typical home outlet in the US can deliver 1.8 kW of power. It would take an excruciating 48 hours or more to charge a modern EV from a home socket like this.

In contrast, modern EV charge ports can carry anywhere from 2 kW up to 350 kW in some cases, and require highly specialized connectors to do so. Various standards have come about over the years as automakers look to pump more electricity into a vehicle at greater speed. Let’s take a look at the most common options out in the wild today.

“Type 1” aka SAE J1772

AC, single phase.

The SAE J1772 standard was announced in June 2001, also known as the J Plug. The 5-pin connector supports single-phase AC charging at 1.44 kW when hooked up to a standard home power socket, ramping up to a full 19.2 kW when installed on a higher-speed EV charging station. The connector carries single-phase AC power on two conductors, signalling on two further conductors, with the fifth being a protective earth connection.

The J Plug became mandatory for all EVs sold in California after 2006, and quickly caught on in the USA and Japan, with some penetration into other worldwide markets.

“Type 2” aka Mennekes

AC, single or three phase.

The Type 2 connector, also known for its creator, German manufacturer Mennekes, was first proposed in 2009 as a replacement for SAE J1772 in the European Union. It’s headline feature is that its 7-pin connector design can carry single-phase or three-phase AC power, allowing it to charge vehicles with at up to 43 kW. In practice, many Type 2 chargers top out at 22 kW or less.  It similarly features two pins for signalling pre-insertion and post-insertion, similar to J1772. It then has a protective earth, a neutral, and three conductors for the three AC phases.

In 2013, the EU chose Type 2 plugs as the new standard to replace J1772 and the obscure EV Plug Alliance Type 3A and 3C connectors in AC charging applications. The connector has become widely accepted the European market since then, and is available on many international market vehicles, too.

CCS – Combo 1, Combo 2

AC, single or three phase, DC fast charging

CCS stands for Combined Charging System, and uses “combo” connectors to allow both DC and AC charging. The standard was published in October 2011, and aimed to allow for high-speed DC charging to be easily implemented on new vehicles. This would be achieved by adding a pair of DC conductors to existing AC connector types. CCS comes in two main forms, the Combo 1 connector and the Combo 2 connector.

The Combo 1 features a Type 1 J1772 AC connector paired with two large DC conductors. Thus, a vehicle with a CCS Combo 1 connector can hook up to J1772 chargers for AC charging, or a Combo 1 connector for high-speed DC charging. This design was intended for vehicles on the US market, where the J1772 connector had become commonplace.

The Combo 2 connector features a Mennekes connector paired with two large DC conductors. Intended for the European market, this allows cars with a Combo 2 socket to charge on single or three phase AC with a Type 2 connector, or to hook up to a Combo 2 connector for DC fast charging.

CCS allows for AC charging as per the standards of either the J1772 or Mennekes subconnectors built into the design. When used for DC fast charging, however, it allows for lightning-fast charge rates up to 350 kW.

Notably, DC fast chargers with the the Combo 2 connector eliminate the AC phase connections and neutral from the connector, as they are unneeded. Combo 1 connectors leave them in place, though they are unused. Both designs rely on the same signalling pins as used by the AC connector in order to communicate between vehicle and charger.

Tesla

AC single or three phase, DC fast charging

DC fast charging

Issued by the Standardization Administration of China, the GB/T 20234.3 standard covers a connector capable of both single-phase AC and DC fast charging. Virtually unknown outside China’s unique EV market, it’s rated to run at up to 1,000V DC and 250 amps, providing charging speeds up to 250 kW.

It’s unlikely you’d find this port on a vehicle that wasn’t built in China, and intended for its own market or perhaps those countries it has strong trade relationships with.

Perhaps most interesting about this port design are the A+ and A- pins. These are rated for up to 30 V and up to 20 A of current. They’re described in the standard as being for “low voltage auxiliary power supply provided by the off-board charger for the electric vehicle.”

Their exact function isn’t clear from that translation, but they may be intended to help jump-start an EV that has completely dead batteries. When an EV’s traction battery and 12V battery are both dead, it can be difficult to charge the vehicle as the car’s electronics don’t have any power to wake up and communicate with the charger. Nor can contactors be energized to connect the traction pack to the car’s various subsystems. These two pins may be intended to provide enough juice to run the car’s basic electronics and energise contactors so that the main traction battery can be charged even if the vehicle has absolutely no power. If you know more about this, feel free to let us know in the comments.

CHAdeMO

DC fast charging

CHAdeMO is a connector standard for EVs that was built first and foremost for fast-charging applications. It can deliver up to 62.5 kW via its unique connector. It was the first standard that aimed to provide DC fast charging to EVs regardless of manufacturer, and features CAN bus pins for communication between vehicle and charger.

The standard was proposed in 2010 for global use, backed by Japanese automakers. However, the standard has only really caught on in Japan, with Europe sticking to Type 2 and the US going with J1772 and Tesla’s own connector. The EU at one point considered mandating a complete phase-out of CHAdeMO chargers, but instead settled for a requirement that charging stalls “at least” feature a Type 2 or Combo 2 connector instead.

A backwards-compatible upgrade was announced in May 2018, which would allow CHAdeMO chargers to deliver up to 400 kW, eclipsing even CCS connectors in this area. Proponents of CHAdeMO cited its nature as a single standard around the globe, versus the split between US and EU CCS standards. However, it has failed to find much purchase outside the Japanese market.

A CHAdeMo 3.0 standard has been in development since 2018. Known as ChaoJi, it features a completely new 7-pin connector design, developed in partnership with the Standardization Administration of China.  It hopes to increase charging rates up to 900 kW, running at 1.5 kV and delivering a full 600 amps through the use of liquid-cooled cabling.

Summary

Reading this article, you could be forgiven for thinking that there’s a whole mess of different charging standards ready to give you headaches wherever you drive your new EV. Thankfully, it’s not really the case. Most jurisdictions have worked to support one charging standard to the exclusion of most others, leading to most vehicles and chargers in a given area all being compatible. The exception, of course, is Tesla in the US, but they also have their own dedicated charging network.

While there are a few people that have gotten stuck with the wrong charger in the wrong place at the wrong time, they can often get by with an adapter of some sort or other where needed. Going forward, most new EVs are sticking to the established charger types in their region of sale, making life easier for everyone.