You're talking about "perpetual motion". Problem is, it will not work. Any kind of wind turbine will create more drag than it is worth. Using more energy than it produces. What could work is solar panels all over the top of the trailer (a big area). That would only help extend range, and of course they don't work at night. The other thing that helps extend range is regenerative braking, which (to make it simple) turns the motor into a generator when the brakes are applied or during decelleration/coasting, charging the battery. Most battery/hybrids already have some form of this.
