Vehicle Systems
Drivetrain
The car is powered by a 36-volt lead-acid battery system that channels its power to the motor through motor controller to a separately-excited DC brush motor. The motor controller provides for both speed control and regenerative braking.
Our motor comes from D&D Motor Systems and, as previously mentioned, is a DC brush motor. It is separately excited, meaning that the field and armature can be independently controlled which is important to us in terms of regenerative braking capabilities. It has enough power to propel the lightweight car and rider / cargo up slight inclines at a speed of up to 25 miles per hour.
The controller is a Curtis 1266 SepEx DC motor controller to be used with separately-excited DC motors. It can provide up to 275 amps of current to the motor's armature (rotor) winding. The controller has built-in regenerative braking capabilities, taking advantage of the generator action of the motor with the field energized with reverse-polarity current to use the vehicle's deceleration to partially recharge the battery. These type of controllers are common in golf carts are proven, robust technology.
The batteries are three Trojan 12V, 225 amp-hour flooded lead-acid batteries. They will provide for a decent amount of runtime on a single charge, but as a tradeoff the batteries are quite large and add considerable weight to the vehicle. The decision on which batteries to use was undertaken jointly with the mechanical engineering team that designed and built the frame, while the purchase of the motor and controller were done prior to the electrical engineering team joining the project.