How the Venturi Astrolab Works

The Venturi Astrolab.
The innovative Venturi Astrolab concept explores zero-emissions commuting in a green future.
Michel Zumbrunn/Courtesy of Venturi

Venturi Automobiles is a vibrantly creative builder and marketer of groundbreaking electric vehicles. Over the past seven years, this Monaco-based company has shown a series of advanced but buildable concepts that have made Venturi a leader in emerging transit technologies. In this article, we'll look at the Venturi Astrolab Solar Commuter, an intriguing electro-solar hybrid that combines an athletic yet graceful design with extreme energy efficiency.

The Astrolab name is itself a hybrid, derived from the Latin word for "star" (astro) and the verb "to take" (labe). The name underscores the fact that the vehicle can store and use energy taken from the sun. Onboard solar panels allow the Astrolab to replenish its batteries to a limited extent, even while in motion. They can also be charged via a plug-in electric power source.


Venturi introduced the Astrolab at the 2006 Geneva Auto Show, where it was hailed as a pioneering autonomous-energy vehicle. In 2007, Venturi sent the Astrolab to Los Angeles. It was driven in city traffic, inspected by the mayor and displayed at that year's Wired NextFest Show [source: Edmunds].

Designer Sacha Lakic made sure the Astrolab weighs as little as possible. Minimizing vehicle mass helps maximize performance with a relatively compact and lightweight motor and battery pack. Seeking inspiration, Lakic looked to another vehicle where minimal weight means everything: the Formula 1 racing car. Borrowing from racing technology, the Astrolab has a carbon chassis, with aluminum front and rear suspension units. This intense focus on minimizing mass paid off -- Astrolab has an empty weight of just 617 pounds (280 kilograms).

The Astrolab carbon-fiber main body has aqua-dynamic lines that could have been inspired by modern racing yachts. The nautical comparisons don't stop there: Venturi observes that riding in their electric roadster is very much like sailing in a sailboat -- you glide along silently and effortlessly, propelled by natural energy.

On the next page, we cast some light on Astrolab's size, seating and power unit.


Venturi Astrolab Design

Trim and sporty, the Astrolab's design is very purposeful and practical. How so? Its solar panels cover 11.8 square feet (38.75 square meters) of horizontal surface. Yet, the car's overall length measures just 12.4 feet (3.8 meters) long, while overall width measures 1.84 meters (6 feet) long. The wheelbase is 98 inches (2.5 meters) long.

The passenger-seating tub is contained within a lightweight protective cell. Formula 1 engineers used similar designs to keep their drivers safe in high-speed collisions. The two passenger seats are arranged in tandem and centered within the vehicle. Their placement helps maintain the ultra-light vehicle's dynamic ride, even with two people aboard.


The Astrolab is powered by an air-cooled 16 kilowatt electric motor rated at 3,500 revolutions per minute (rpm). It produces 50 newton-meters (37 pounds/feet) of torque. A liquid-cooled NiMH Venturi NIV-7 battery pack provides energy to operate the motor. Innovative battery charging technology allows the Astrolab to restitute battery energy from either the onboard solar panels or plug-in charger.

The photovoltaic cells in the Astrolab's solar panels are covered with nano-prisms that concentrate solar energy very effectively. The car's four-wheel disc brake system also converts energy generated during braking into stored electric power. It takes five hours to fully recharge the car's battery pack using the onboard plug-in charger.

Since the Astrolab can be operated solely on stored solar energy, it can be driven without using fossil fuels -- even indirectly. When running on solar power, it is a true zero-emissions vehicle. Electricity taken from the power grid through plug-in charging may or may not be produced by fossil fuels. However, Venturi says environmental actions taken while making their vehicles will more than offset any greenhouse gases created during production of the electricity used to power them.

On the next page, we look at the Astrolab's performance and sum up the pioneering concept's accomplishments.


Pointing the Way to Zero-Emissions Driving

The Venturi Astrolab's solar cell technology.
A film embedded with nano-prisms covers Astrolab's solar cells, maximizing their ability to capture energy from the sun.
Michel Zumbrunn/Courtesy of Venturi

Extensive road testing of the Astrolab concept has proven it worthy of daily commutes. If it starts out with a full charge, the Astrolab can travel up to 68 miles (110 kilometers) before its batteries need to be refreshed. Solar energy gathered on an average day by the solar cells contributes about 11 miles (18 kilometers) to the Astrolab's range. Its top speed is reported to be 75 mph (120 kilometers per hour).

Venturi says the battery pack, which weighs 238 pounds (108 kilograms), is good for more than 2,500 charging cycles. Based on anticipated normal use, the batteries should last for at least 10 years.


What does the future hold in store for the Astrolab? Well, don't expect to buy one any time soon. Venturi plainly states, "The Venturi Astrolab is for now a concept car and won't be commercialized. We developed it to show how far we can go with the photovoltaic technology and to prove that an electric car can have very good performance with little energy."

Venturi says it has gained a considerable head start on electro-solar vehicle development with the Astrolab. "It meets the needs of people's inter-urban travel," the firm says, adding, "It is at the forefront of the best that is being achieved in terms of technology." Venturi is very pleased with the solar yield produced by the Astrolab's solar panel. They say the advances made with the Astrolab "allow us to hope for even higher yields in the years to come."

Has this lightweight car that takes energy from the sun given us a glimpse into a fully green future, where we'll need only daylight to power our transportation? Time will tell.


Lots More Information

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  • "Solar Powered Cars." March 31, 2009.
  • Automotive Design Conference. "Auto(r) Sacha Lakic." March 24, 2009.
  • Bilan Carbone UK "The Bilan Carbone┬« method for assessing greenhouse gas emissions." March 28, 2009.
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