I asked the same question about why it took so long, Rob. Their answer is a logical one. Getting a consensus of 190 technical specialists is difficult. That reason apparently didn't stop the ChaDeMo standard, however.
Most homes have single-phase AC, Beth, which won't cut it for fast charging. Fast charging requires three-phase AC (and the associated higher voltages and currents), which is typically used in industrial applications today. In contrast, today's home-charging systems usually use single-phase AC at 120V and 15A (about 16 hours or less) or single-phase AC at 240V and 15A (about 8 hours or less). SAE's new standard calls for up to 200A and up to 500V. Making those modifications to a home would be very expensive.
Beth, my guess is right about the voltage in the home. I think the important part of this development is that it could free the EV to travel beyond short trips from the home. Waiting 10 or 20 minutes at a public charging station is not that inconvenient.
Beth, I think that the issue with using this standard for home use is the current draw. Typical service to a home is 200A. This would use as much. I guess if you were willing to turn off everything in your home then you could use it. It is not only what is in your home that matters, but the infrastructure serving it. This would require a big upgrade in that. Commercial locations will have new infrastructure, thus will be able to deal with the current draw.
Definitely an important development and I, too, wonder what took so long. But then again, everything seems to take long in this segment of the market.
Also confusing to me is why does this have impact on commercial and public charging stations, but not for home use? Is it something to do with the voltage and residential infrastructure. Seems to me they'd want to address that.
Nice story, Chuck. It's amazing that the change in a standard would have that big an effect on charging hybrids and EVs. Makes you wonder why it took so long, especially on a feature that has such impact on hybrid and EV owners. This standard means you could actually take a trip with an EV.
In many engineering workplaces, there’s a generational conflict between recent engineering graduates and older, more experienced engineers. However, a recent study published in the psychology journal Cognition suggests that both may have something to learn from another group: 4 year olds.
Conventional wisdom holds that MIT, Cal Tech, and Stanford are three of the country’s best undergraduate engineering schools. Unfortunately, when conventional wisdom visits the topic of best engineering schools, it too often leaves out some of the most distinguished programs that don’t happen to offer PhD-level degrees.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.