[Fifteen15Five5]

Why can't you put induction air ports in the sides or top of a smart that would take the flow of air to turn an alternator that would charge the batteries??

[Curlyben]

Possibly, but the increased drag may mean it's not really an option.

[ebaines]

I don't see the advantage. First, the smart car has a traditional internal combustion engine (it's neither an electric car nor a hybrid) though its engine is pretty small compared to most cars on the road. It's not clear that adding a wind turbine to charge its starting battery would be more efficient than using the traditional alternator that most cars use.

If your question was intended to be about a charging method for a electric car or hybrid, putting a wind turbine on such a car would create more loss of power through increased drag than it would generate, so it would not help. The only exception would be when you're trying to slow the car which is when drag would be a good thing. So perhaps a system with a turbine that engaged when the brakes are applied but otherwise was somehow stowed out of the way of the airstream could work, but I suspect its cost would be pretty hgh and its beneficial effects rather modest.