Getting a Charge from the Chevy Volt

This story was written by CNET's Martin LaMonica

On Tuesday, I visited the sprawling Milford Proving Grounds in southeastern Michigan, where General Motors vehicles have been put through the paces since the 1920s.

I was one of the lucky few who got the last ride of the day in a mule, or test version, of the Volt, which was "almost stolen" from the car's development team by Frank Weber, the global vehicle line executive for the Volt, to give journalists a taste of the upcoming plug-in electric sedan.

In addition to being a key figure in the Volt's development, Weber clearly has got a car engineer's love of driving. His high-speed tour around the track gave me a feel for the "driving experience" GM executives tout with the Volt, which is due late next year.

I was prepared for the zippy acceleration. Models will vary of course, but electric vehicles can boast great acceleration--the Tesla Roadster is faster off the line than many sports cars, for instance--and they deliver their full torque at all speeds.

What surprised me though was the handling. As Weber dipped around the couple turns we took, the car seemed to really stick to the road, and I didn't slide off my seat at all.

It makes sense that it felt like the car "hugged" the road. The large, 400-pound battery pack, which is positioned under the back seats, gives the Volt a low center of gravity, and the car has a good weight distribution, GM executives said.

During the drive, Weber--obviously enamored with its performance--said that you feel much closer to the electric car when you drive because of the responsive acceleration. "It's more like flying than driving a vehicle," he said. And, of course, the ride was very quiet as the car was running on batteries.

I've never taken a Lamborghini or Ferrari around a test track, but I can say the Volt's acceleration and handling are noticeably sportier than sedans like the Prius or the alternative fuel SUVs I also drove at Milford.

Watching the video, you can get a feel for how Weber showed off the Volt's acceleration and, on the last turn, the handling.

Under construction

Earlier in the day, I took a tour of GM's pre-production facility at its Tech Center in Warren, Mich., where I gained a bit more insight into the interplay between the Volt's two power sources--its batteries and the internal combustion engine.

The power train, which GM is likely to use in other cars, is designed to go 40 miles on the car's batteries. After that, the engine, which can run on gasoline or E85 ethanol, kicks in. But the car is always running off the electric motors. By contrast, a regular, or parallel, hybrid, nearly always uses both the battery and gasoline engine together.

During the factory tour, though, I learned that it's a tad more complicated than simply switching from battery to gas after 40 miles--one reason why determining miles per gallon is so tricky.

The battery pack, which takes about eight hours to charge in the U.S., holds 16 kilowatt-hours of electricity, half of which the car will use to go 40 miles. After that, the engine turns on to run the generator that charges the battery, a switch that should be transparent to the driver.

What happens if you need access to the car's full power to get up a mountain on a long ride? For those demanding situations--in electrical terms, when the car needs more than 50 kilowatts of juice--the Volt will draw on some of the remaining stored energy in its battery pack, explained Andrew Farah, the chief vehicle engineer.

When the car dips into that "buffer," the gasoline engine acts to sustain the battery level so that it doesn't go too low, which would strain the batteries, he said. "We're operating between 30 percent and 80 percent (charge). It's important for the battery life," he said. All along, the battery can be charged with regenerative braking and during deceleration.

For consumers to gauge car charging, an indicator on the top of the dash below the windshield will show when the car's batteries are full. The Volt will also get a power cord and holder to show the owner that a car is getting a charge from a socket.

Weber said drivers will be able to communicate with the car to schedule charging via OnStar or the Web. People will be able to get off-peak rates and override the set schedule, he said. "It will almost be like using a thermostat," he said.

To see a test drive of GM's plug-in hybrid SUV under development, watch this YouTube video:

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By Martin LaMonica