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DC fast charging not as damaging to EV batteries as expected

As convenient as DC fast charging is, there have been lots of warnings that repeated dumping of so many electrons into an electric vehicle's battery pack in such a short time would reduce the battery's life. While everyone agrees that DC fast charging does have some effect on battery life, it may not be as bad as previously expected. Over on SimanaitisSays, Dennis Simanaitis, writes about a recent presentation by Matt Shirk of the Idaho National Laboratory (INL) called DC Fast, Wireless, And Conductive Charging Evaluation Projects (PDF) that describes an ongoing test of four 2012 Nissan Leaf EVs that are being charged in two pairs of two. One pair only recharges from 50-kW DC fast chargers, which the other two sip from 3.3-kW Level 2 chargers exclusively. Otherwise, the cars are operated pretty much the same: climate is automatically set to 72 degrees, are driven on public roads around Phoenix, AZ and have the same set of dedicated drivers is rotated through the four cars. "Degradation depends more on the miles traveled than on the nature of recharging." What's most interesting are the charts on page seven of Shirk's presentation (click the image above to enlarge), which show the energy capacity of each of the four vehicles. When they were new, the four batteries were each tested to measure their energy capacity and given a 0 capacity loss baseline. They were then tested at 10,000, 20,000, 30,000 and 40,000 miles, and at each point, the DC-only EVs had roughly the same amount of battery loss as the Level 2 test subjects. The DC cars did lose a bit more at each test, but only around a 25-percent overall loss after 40k, compared to 23 percent for the Level 2 cars. Simanaitis' takeaway is that, "INL data suggest that the amount of degradation depends more on the miles traveled than on the nature of recharging." The tests are part of the INLs' Advanced Vehicle Testing Activity work and a final report is forthcoming. These initial numbers from IPL do mesh with other research into DC fast charging, though. Mitsubishi said daily fast charging wouldn't really hurt the battery in the i-MiEV and MIT tests of a Fisker Karma battery showed just 10-percent loss over 1,500 rapid charge-discharge cycles.

This map reveals the cleanest vehicles based on location

Naysayers love to point out how dirty the electricity grid mix is when it comes to charging electric vehicles. Curmudgeons are eager to jump into any conversation about EVs to enlighten the lucky listeners about how plug-in cars contribute to pollution, sometimes even throwing in a dash of climate-change denial for good measure. (Thanks, buddy. Pray, tell me more about the plight of oppressed SUV owners.) Unless someone buys an EV just because they think they're cool (which, yeah, they often are), they probably have at least a passable understanding of their environmental pros and cons. As many EV owners are already aware, location has a lot to do with any particular plug-in car's carbon footprint. Still, there's always more to know, and knowledge is not a bad thing, especially if one uses it to do the right thing. That's why this handy-dandy map from Carnegie Mellon University is so interesting. CMU researchers have compiled information about the lifecycle greenhouse gas emissions of various EVs based on where they're charged, as compared to gasoline-powered vehicles. The researchers looked at the Nissan Leaf, Chevrolet Volt, and Prius Plug-In Hybrid versus the gasoline-dependent Toyota Prius hybrid and the stop-start-equipped Mazda3 with i-ELOOP and compared grams of CO2 emitted per mile. CMU takes into account the grid mix, ambient temperature, and driving patterns. CMU takes into account the grid mix based on county, as well as ambient temperature and driving patterns in terms of miles traveled on the highway or in the city. For instance, if you drive a Nissan Leaf in urban areas of California, Texas, or Florida, your carbon footprint is lower than it would be if you were driving a standard Toyota Prius. However, if you charge your Leaf in the Midwest or the South, for the most part, you've got a larger carbon footprint than the Prius. If you live in the rural Midwest, you'd probably even be better off driving a Mazda3. Throughout the country, the Chevrolet Volt has a larger carbon footprint than the Toyota Prius, but a smaller one than the Mazda3 in a lot of urban counties in the US. The Prius and Prius Plug-In are relatively equal across the US. Having trouble keeping it straight? That's not surprising. The comparisons between plug-in and gasoline vehicles are much more nuanced than the loudest voices usually let on.

Japan plans real-world diesel emissions test after companies fail

Japan's transport ministry plans to start real-world diesel emissions tests after an experiment found four models from Toyota, Nissan, and Mitsubishi that produced more nitrogen oxide (NOx) emissions than the nation's rules allow, according to The Japan Times. Regulators there usually only perform emissions checks in the lab. The VW diesel scandal has everyone double-checking their figures. Diesel versions of the Toyota Hiace van, Land Cruiser Prado, and Nissan X-Trail produced up to 10 times more NOx than allowed. The Mitsubishi Delica D:5 was up to five times over the limit, The Wall Street Journal reports. There was no evidence of defeat devices in the vehicles. Mazda performed well in the experiment, though. The CX-5 passed with nearly the same results on the road and in the lab. The Demio, better known as the Mazda2, did nearly as well with only slighter higher figures in the real world than in the controlled setting. The experimenters theorized the reason for the excessive emissions was that cold weather caused the engines' software to shut off the exhaust gas recirculation to prevent damage, according to the WSJ. However, this behavior also increased NOx production. Toyota, Nissan, and Mitsubishi don't have to worry about punishment from the transport ministry because this check was just an experiment. Their models already passed the mandated lab tests, which was the only requirement, according to The Japan Times. As governments begin greater real-world emissions tests, the results suggests diesels aren't very clean. A recent check in France found models from Ford, Renault, and Mercedes-Benz that didn't perform up to the standards. Regulators in India conducted similar evaluations and ordered VW to recall over 300,000 vehicles. Related Video: