Taking one more key step in the process of moving electric vehicles closer to mass marketability, the Society of Automotive Engineers (SAE) has formally approved a uniform standard that defines the cable and connector configurations to be used in all electric and plug-in EVs sold here in North America. A work in process for the past two and a half years, this universal hardware design was developed by the SAE Hybrid J1772 Task Force in concert with both auto and charging equipment manufacturers as well as suppliers, utility companies, national labs and various institutions of higher education.
At the heart of the new SAE J1772 standard is a charging interface based on a 43-millimeter five-pin coupler that will be employed by all manufacturers and recharging systems, both personal and commercial. This new conductive charging cable/coupler setup is capable of accommodating both 120-volt and 240-volt single-phase electrical systems at up to 70 amps of power. It can also support two-way communications over power lines, which will allow for the implementation of optimized load balancing on power grids and on/off-peak charging.
Already given full approval by the Underwriters Laboratories for safety and durability elements, the SAE J1772 system is designed to last for 10,000 charging cycles -- which under normal operating conditions should last the average individual owner more than 25 years of typical usage -- and be totally impervious to all temperature and weather conditions. Manufacturers are expected to officially give their approval to the SAE's J1772 standard within the next week or two.
According to Gery Kissel, chairman of the SAE Hybrid Task Force and an engineering specialist who is also working on the Chevy Volt, the key goals of SAE J1772 were to make sure that it would bring about a consistent, reliable and uniformly beneficial solution. "By standardizing, you're reducing costs and allowing everyone to use the same connector. All of the charging equipment you would pull up to in public would have identical connectors, so any vehicle could use one." While the J1772 coupler design also has been accepted for use by the Japan Automotive Research Institute (JARI), the European market, which uses a three-phase rather than a single-phase electric infrastructure, has approved a different connector package that conforms to design requirements of the system in place there.