The Electrovair II Experimental vehicle was built in 1966 and was GM's second post-war attempt at developing a viable electric vehicle. The Electrovair II addressed the problem of lead-acid battery weight and package size demonstrated with its predecessor by utilizing a new battery technology, silver zinc. This battery development delivered power in a package three times lighter and considerably smaller than lead-acid batteries. The Electrovair II showed promise, but it experienced the same limitations that have restricted electric car acceptance; limited range and frequent recharging requirements.
Even as far back as the mid-1960s, General Motors was earnestly exploring futuristic vehicles with alternative power sources, including electric; and this 1966 Electrovair II concept was a test bed for electric motor and control development. It was actually GM's second attempt at an electric-powered Corvair. But when the first one didn't meet the engineers 'hoped-for performance' they started from scratch with a new one using a 532-volt silver-zinc battery pack stuffed into its front truck and what had been its rear engine compartment.
Because it used comparatively light and compact silver-zinc batteries, the Electrovair II weighs about 800 pounds more than a standard Corvair, where an equivalent pack of conventional lead acid batteries would have weighed closer to 2,600 pounds. The silver-zinc batteries also offered good energy storage and high peak power, but their downsides were high cost and the unfortunate reality that they were essential worn out after only about 100 recharges. The car's 115 horsepower AC-Induction motor that provided acceleration competitive with the gasoline version and an 80-mph top speed. Its major disadvantage was a driving range of only 40-80 miles before recharging.
Strictly an engineering exercise, the Electrovair II was never intended for production. With relatively stable and cheap gasoline prices in the mid-1960s, the American public wasn't exactly clamoring for electric cars at the time.