More from Popular Mechanics

Don't call the Volt a plug-in hybrid. GM engineers steadfastly claim that the Volt is an electric vehicle with an on-board generator, or in their words, an "EV with a range extender." We tend to favor the former. Semantics aside, the Volt is the most thoroughly tested car in GM's history, a new type of vehicle that vehicle line director Tony Posawatz claims is overengineered because, "Frankly, we have to change minds about the quality of GM vehicles." Ever since the concept debuted in Detroit in 2007, we've covered every tidbit Chevy felt worthy to release. Now, we've finally spent three unsupervised days and over 900 miles in the car that has been called "GM's moonshot." Does it deliver?

The Specs
With a 105.7-inch wheelbase and 177.0-inch exterior length, the Volt is about the same size as the upcoming Chevy Cruze, a car that shares some of the Volt's underpinnings. The big difference of course is that the Volt's 16 kwh T-shaped lithium-ion liquid-cooled battery pack fills the center tunnel and most of the area beneath the rear seats, where the fuel tank normally resides.

The battery leaves room for only four seats and is the Volt's prime power source. After charging the battery, which takes about 11 hours with a standard 120-volt outlet and less than half that time with a 220-volt line, the Volt silently motors and recaptures some energy during braking. GM estimates the Volt can travel between 25 and 50 miles before depleting a fully charged battery.

The car could likely travel longer on the juice, but GM engineers treat the battery with kid gloves. In normal use, the car only uses roughly half of the battery's 16-kwh worth of energy storage, never deeply discharging it or overcharging. This strategy, GM says, will ensure the Volt battery meets the eight-year, 100,000-mile warranty.

When the car's computer decides that the battery is discharged, the Volt's 1.4-liter four-cylinder engine kicks on to spin the 74-horsepower on-board generator. Once in this charge-sustaining mode, the engine does not top off the battery charge, but simply runs long enough to maintain performance. An electronically controlled clutch connects the engine to the generator.

The generator and 149-hp traction motor are connected by a planetary gearset to the wheels in a way that's similar to the transmission in the Toyota Prius. This arrangement allows both electric motors to power the wheels, a strategy that keeps each motor in its most efficient — and refined — operating mode.

As befitting this next-gen car, two seven-inch WVGA screens — one in the center console, the other in the gauge cluster — display relevant information and, of course, an efficiency coach with vibrant graphics. There's even a tutorial mode. While the standard heated seats and power windows seem like power hogs in an EV, the engineers counter that both actually save energy by encouraging drivers to open the windows in the summer and use less heat in the winter.

Capacitive-touch sensors operate basic functions like HVAC and the audio systems. There's also a smartphone app that allows user to specify start times and to precondition the cabin while the car is still plugged in.

The Volt will be monitored as never before thanks to GM's OnStar service. The usually pay-by-the-month feature will be free for five years on the Volt, primarily so data about the car and the health of the battery can be beamed back to GM HQ.