Electric Car Driving Range Extension by a Towed Generator System

PROBLEM: Many potential buyers of electric cars are very concerned about the driving range. These buyers occasionally have to make trips which are beyond the 35- 65 mile range of most pure electric vehicles. Some of these trips will be to places without charging stations, or over a long distance. The limited range of most electric vehicles deters many potential users who may have only a few long range trips.

SOLUITON: Take charging capacity with you with small gasoline powered generator system towed behind the electric car. A small generator supplying about 80-90% of the power used when cruising at 60 mph would slow the discharge of the car's main batteries, allowing a 5 times or more improvement in range. When parked, the generator would provide power to recharge the main batteries.

These generator system could be rented from electric car dealers or rental car companies. They would be attached and detached by a trained technician. Daily rental cost should be a less that the rental cost of a subcompact car, since the generator system is similar to a part of the drivetrain of a small car.

Benefits: Range becomes less of an issue for the small number of trips which are beyond the average range. Since occasional rental helps spread the capital cost of the generator system over many users, the costs of occasional rentals should still be well under the cost savings of switching to an electric vehicle. This should make an electric car more feasible as a first or second car for a wider spectrum of people, and the use of electric cars should decrease petroleum use.

Penalties and Costs: The additional weight will make acceleration slower, but many electric cars have more than sufficient acceleration. The turning radius and parking would also be affected, and gasoline use would be be higher than a dedicated hybrid car.

Additional Considerations
The generator system would have radio and ultrasound detectors to detect when the generator was in an enclosed space, such as an underground parking garage. Generator operation would electronically locked out in closed environments. The system would have GPS and location reporting to track assets and reduce theft.

The system would “twin” the functions of the car's brake and turn signal, similar to most trailers. The tops of the turn signals would be mounted high enough that they would be visible in the rear view mirror of the electric car. This visibility would tend to reduce accidents from drivers forgetting the towed generator was present when backing up. A rear view camera would be provided to assist reversing.

Bill McDonald billmcdonaldsiliconvalley