A 1912 Baker Electric car that was retrofitted with a solar panel by Charles Escoffery for the International Rectifier Corp. back in 1960. The panel cost $20,000. (I don't know what that would be in present-day money, but it wouldn't be cheap.) With the panel, the Baker could run at 20 mph for three hours. International Rectifier hoped to soon be churning out "noiseless, smogless" solar cars for $5000 each. It's 53 years later now, and we're still waiting.