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CHAPTER 5Chassis and DesignA 20-hp electric motor will easily push your 4,000-lb. vehicle at 50 mph.The chassis is the foundation of your electric vehicle conversion. While you mightnever build your own chassis from scratch, there are fundamental chassisprinciples that can help you with any EV conversion or purchase—things thatnever come up when using internal combustion engine vehicles—such as the influenceof weight, aerodynamic drag, rolling resistance, and drivetrains.This chapter will step you through the process of optimizing, designing, and buyingyour own electric vehicle. You’ll become familiar with the chassis trade-offs involved inoptimizing your EV conversion. Then you’ll design your EV conversion to be sure thecomponents you’ve selected accomplish what you want to do. When you have figuredout what’s important to you and verified your design will do what you want, you’lllook at the process of buying your chassis.Knowledge of all these steps will help you immediately (when reading aboutChapter 10’s pickup truck conversion), and eventually (when picking the best EVchassis for yourself). The principles are universal, and you can apply them whetherbuying, building, or converting.Choose the Best Chassis for Your EVThe chassis you pick is the foundation for your EV—choose it wisely. That’s the messageof this chapter in a nutshell. Since you’re likely to be converting rather than buildingfrom scratch, there’s not a lot you can do after you’ve made your chassis selection. Thesecret is to ask yourself the right questions and be clear about what you want toaccomplish before you make your selection.Like a youngster’s soapbox derby racer, you want a chassis with an aerodynamicshape and thin wheels, so that you can just give a shove and it runs almost forever. Butits frame must also be big enough and strong enough to carry you and your passengersalong with the motor, drivetrain/controller, and batteries. In addition, if you want todrive it on the highway, federal and state laws require it to be roadworthy and adhereto certain safety standards.The first step is to know your options. Your EV should be as light in weight aspossible; streamlined, with its body optimized for minimum drag; optimized forminimum rolling resistance from its tires, brakes, and steering; and optimized forminimum drivetrain losses. The motor-drivetrain-battery combination must match thebody style you’ve selected. It must also be capable of accomplishing the task mostCopyright © 2009 by The McGraw-Hill Companies, Inc. Click here for terms of use.95