when they start production at their new Tennessee plant in 2012. The Tesla Roadster already supports 16.8 kW charging and the Tesla Model S will support up to 20 kW charging. For driving around town, and charging overnight, it’s not a big deal, but for trips beyond the single-charge range, high power Level 2 charging matters a lot.
DC Quick Charge
DC quick charge means charging at even higher levels from an external charging unit. By moving the electronics and smarts needed to manage charging outside the car, we can have faster charging without putting expensive high power management electronics into the car. This offers both opportunity and challenges. Because more of the charging electronics move outside the car, there are more issues in creating a standard every automaker can use. Higher power means more safety issues and the connector needs to
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be larger to carry more power, again creating more complexity in creating a universal standard. There’s a standards war going on right now over DC Quick Charging. Nissan is using a standard widely deployed in Japan called CHAdeMO. The LEAF has an option for a CHAdeMO port to support DC quick charging that will charge an empty battery pack to 80% in under 30 minutes. Meanwhile, the American automakers are resisting CHAdeMO and working with SAE to create a different standard. At best, the SAE standard is a couple of years away from being adopted and deployed. Maybe CHAdeMO will win by being first. Maybe a new SAE standard will become the dominant standard in two to five years. Hopefully we won’t have some huge number of LEAFs and other EVs with CHAdeMO ports and nowhere to charge. Meanwhile, Tesla Motors isn’t satisfied with CHAdeMO, doesn’t want to wait for SAE, and wants a better
connector than either. They have told Model S reservation holders they plan to use a custom, compact connector that they claim will support 90 kW charging, nearly twice the rate of the current CHAdeMO stations. Will Tesla be successful in deploying their own proprietary charging network? Will their connector design shame SAE into picking a design that’s less unwieldy than the current prototype? We’ll see. DC quick charge stations require big power feeds and expensive electronics. I’ve heard a single station can cost between $25,000 and $100,000, although Nissan has recently announced a CHAdeMO station for just under $10,000. That’s a lot of capital investment to make back selling a cheap commodity. While EV drivers may be very happy to pay a large premium over the cost of electricity for the convenience of quick charging, most people will rarely need it. DC quick charge is also hard on
Photo courtesy of Tom Saxton
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