It is an interesting piece of recent electric vehicle (EV) history that the Tesla not only has two different charging plugs for different markets, but they also differ to the ones chosen by the other EV manufacturers.
In this article I will contend that this is not really due to Tesla ‘wanting’ a separate plug standard to the rest of the world – more it is because they needed them right then, and could not delay waiting for the rest of the world’s EV manufacturers to catch up.
The marketing advantage of having a bigger (and Tesla-only) DC charging network than everybody else is in fact a happy accident. (Although it may also become a millstone as the non-proprietary CCS DC charging system is now rolling out chargers that are three times faster than the Tesla DC Supercharger).
Firstly – in 2008 when the Tesla Roadster was first released, Tesla needed a robust plug for general AC charging, as well as allowing for DC charging capacity. (DC charging was even then recognised by Tesla as being important for making long-distance travel practical).
At that time, there were no internationally agreed standards for either AC or DC car charging. Consequently, Tesla went it alone to develop the first Tesla EV charging plug, as shown below.
This plug design allowed for the peculiar US electricity system that supplies single phase 120V/two phase 240V AC as well as combining a DC charge system into the same plug. This plug design remained the same in the low volume Roadster as it became exported overseas.
It is still also the standard one fitted to Teslas made for the North American and Japanese 120/240V systems that utilise the Tesla superchargers made for these regions.
All in all, it offered a very neat and small footprint plug for incorporating into the bodywork.
Following the Tesla plug design, in 2010 the first international EV charging standards for AC and DC were developed.
With the Japanese vehicle manufacturers becoming the first existing car manufacturers to become interested in EVs – they, in collaboration with TEPCO (Tokyo Electric Power Company) designed quite different plugs to meet these standards that reflected their own engineering and electricity supply system.
Consequently the Japanese plugs (Type 1, or ‘J1772’ for single phase AC and Type 4, or ‘CHAdeMO’ for DC charging) became the norm as the first mass-market EVs rolled out. (These being the iMiEV and the Leaf).
Later EV manufacturers also initially adopted these plugs as it suited their needs and they were not particularly inclined to take up Tesla’s offer to share their plug design and chargers. (Partly because Tesla stipulated that to do so, they had to contribute to the evolving Supercharger network.
Given the scepticism that the major manufacturers had – and to some degree still have – for the longevity of Tesla as an auto manufacturer, it is hardly surprising that they declined the offer!)
Meanwhile, Tesla began exporting Model S EVs with large batteries to the rest of the world where 220 – 240V/400-ish volt three phase systems prevailed.
As three phase 400V AC charging was a much faster option, Tesla adopted the then recently internationally agreed three-phase Type 2 (Mennekes) plug design for the Model S and X in these markets.
So far, so good. Type 2 had also been adopted by many of the European EV manufacturers for use in Europe, so Tesla was looking good for actually sharing chargers with other EVs outside of North America and Japan.
However, the early Type 2 standard also included an option for using two of its AC pins for DC charging, but no other EV manufacturer at the time had big enough batteries to bother much with DC charging. (For instance the original Renault Zoe EV with a 22kW battery could charge in less than 30 min on three phase AC).
As Teslas have large batteries, 3 phase AC alone could not deliver the charging speeds they wanted. Tesla therefore took up the option in the Type 2 standard and adapted two of the pins in the plug to take either AC or DC, depending on the signalling from the charging point.
Unfortunately, it was later decided by the alliance of vehicle and equipment manufacturers who support the Type 2 plug development to incorporate a separate pair of DC pins into the Type 2 design. This also allowed for harmonisation of the design between Type 1 and Type 2.
Thus the Combined Charging System (CCS) system was born: incorporating the Type 1 AC plug as CCS1 in 120V AC countries, and the Type 2 AC plug as CCS2 in 220 – 240V countries.
CCS1 is now becoming the norm in the USA and Canada, and CCS2 is now mandated for Europe (with all Type 1 plugs there to be phased out by 2020) and is by adoption and/or by default becoming the norm in all other 220 – 240V three phase countries (except China).
AND (yet again) Tesla by going first has ended up with a different DC charging system to the rest!
However in this case – the Tesla single and three phase AC chargers are in fact compatible with Mennekes equipped cars (with some caveats).
So what will happen from here? Well, it’s a matter of ‘watch this (charging port) space’!
The reason for optimism for a common standard for vehicle charging ports is that Tesla is now a core member of the CCS alliance. Which begs the question: what charging port will the Model 3 have when it starts shipping to Europe and beyond where 220- 240/400V systems are the norm?
Bryce Gaton is an expert on electric vehicles and contributor for The Driven and Renew Economy. He has been working in the EV sector for 10 years, and also is editor of the Australian Electric Vehicle Association newsletter.