To no one’s surprise, American automakers Ford and GM have agreed on a single EV charging port connector standard that has been in development by the Society of Automotive Engineers (SAE) for several years.  What’s a bit of a surprise in this week’s announcement is that the companies were joined by German automakers BMW, Daimler, Porsche and Volkswagen, while Chrysler is conspicuous in its absence.

The single connector will support fast DC charging as well as be backward compatible with the J1772 AC charger that is standard on many plug-in electric vehicles today. This approach is at odds with the “CHAdeMO” standard for DC charging that was originally designed by the Tokyo Electric Power Company and has been adopted by Mitsubishi, Nissan, and others. (The name is short for “Charge de Move.”)

The split was all but inevitable as SAE took its stance long ago when the organization first started working on a standard that it wanted a different architecture for the communications interface, as we’ve covered here, here, and here.

Chrysler declined to endorse the agreement even though one of its key EV engineers (who recently joined the company from Ford) has worked on the SAE standard since its inception.  Chrysler doesn’t have a commercial plug-in EV (PEV) in the works, and neither the company nor parent Fiat is a member of the CHAdeMO association.

European car companies have been divided on standards for both AC and DC charging, and it is not clear if other OEMs in the region will sign on.  But at least VW and BMW can make cars with one connector for both the continent and North America.

This agreement makes it all but official that DC charging stations currently being installed in the United States (thanks to grants from the DOE) will only be able to serve a portion of the PEV market (namely vehicles from Nissan and Mitsubishi).  Charging stations with more than one port could be upgraded to offer both cable types once the SAE standard is released, but who’s going to pay for the retrofits? Having two fast charging standards could slow the spread of fast charging.  Pike Research expects shipments of DC charging units to grow from less than 3,000 this year globally to more than 115,000 by 2017.

The group also endorsed the HomePlug GP protocol for communications between vehicles and smart grid equipment. Cisco, GE, and utilities Duke Energy and PG&E are contributing to that standard, which will enable PEVs to communicate with a range of home energy devices.