It was a long hiatus, but by the 1960s, GM was looking seriously at electric cars again. Gas cost about 34 cents a gallon, or about $2.00 in today’s terms, but Americans were more concerned about air pollution, according to a GM overview on the Electrovair.
The Electrovair II, a show car unveiled in 1966 seen at right, was an improved version of 1964′s Electrovair I. Both were based on the rear-engine gas-powered Chevrolet Corvair, whose design provided a convenient location for the batteries. The large battery pack went under the hood, while the electric motor drove the wheels from the back of the car.
“The GM electric vehicle concept is based on the belief that an electric car should have performance compatible with modern expressway driving,” press materials for the car said.
The Electrovair II used silver-zinc batteries because, GM said, they delivered high power. (These were the same batteries GM produced for use in intercontinental nuclear missiles, said GM engineer John Berisa.)
The downside was that they were expensive and wore out quickly, as the carmaker admitted at the time. Performance was similar to the gas-powered Corvair, but range was still a problem. The car needed recharging after 40 to 80 miles.
“The objective is to determine what is technically feasible,” GM wrote of its work on cars like the Electrovair, “regardless of whether a project ever will become economically possible.”
The Electrovair II never went to market, and it would still be a long time before a viable electric car would become economically possible for GM.
The battery powered 1966 Electrovair II concept was a test bed for motor and control developments. Its power source was a silver zinc battery pack, in a 532-volt array, located in the front and rear compartments of a 1966 Corvair Monza sport sedan. Silver zinc batteries were used because they delivered high peak power and provided good energy storage but they were costly and were worn out after 100 recharges.
The battery pack was connected to a 115 horsepower AC-Induction motor that produced approximately the same performance as a conventional gasoline powered Corvair, except for its limited range of 40-80 miles before recharging. A tank full of gasoline would propel a Corvair 250-300 miles. Top speed was 80 m.p.h.
Electrovair II’s total weight was approximately 800 lbs. more than a Corvair, even with the comparatively light and compact silver zinc battery pack. If it were propelled by conventional lead acid batteries, the batteries alone would weigh more than 2,600 lbs., approximately the total weight of a standard Corvair.
Some of the touches that set the Electrovair dash apart from the production car are large gages for monitoring volts and amps occupy the space normally reserved for the radio and the in-dash gear selector has no “L” for low.