That depends on the type of battery your car uses. Lead-acid batteries, the kind that you find in gas-powered vehicles, may not last a full year. Other types of batteries -- like lithium-iron-phosphate batteries -- can last up to 10 years or longer.

Although they seem to many people to be a new thing, electric cars have been around for a very long time. In fact, prior to the refinement of the internal combustion engine, electric cars were as prevalent as gas powered vehicles, and even favored by some. As far back as 1897, the Electric Carriage and Wagon Company of Philadelphia produced taxicabs for use in New York and other growing areas, because of their reliability, reasonable speed, low vibration, low noise, and lack of noxious fumes.

Early electric cars were eventually replaced by internal combustion engine powered vehicles because of the ready availability of fossil fuels and the lack of knowledge about environmental concerns. However, as the 20th century drew to a close, environmental awareness drove production of electric vehicles once again. The vehicles remain quite pricy and the large rechargeable batteries that power these vehicles make up most of that expense, so knowing how long the average battery will last is a point of consideration for prospective electric car owners.

To increase consumer confidence, manufacturers have warranted the batteries for time periods deemed pretty long even by internal combustion car standards.

Typically it’s eight years, and mileage is usually at least 100,000 miles. Tesla warranties its 60-kwh Model S to 125,000 miles, and the 85-kwh version gets unlimited miles.

Research has been conducted but in most cases, electric cars looked at were only a year or two old, with well under 100,000 miles, if not less than 50,000 miles. They were all under warranty, but some useful preliminary data can be derived from these.

What may be one of the more useful studies is Plug In America’s look at the Tesla Roadster. This study was done in 2013 just when the five-year warranty of the first Roadsters was ending, and showed Tesla had exceeded early expectations given for its cars.