Concepts

Final Concept

Six new batteries were added to the car in order to achieve more range. The batteries were distributed in the car by adding 6 batteries to the rear of the car next to the 6 existing batteries. The batteries were connected in series/parallel in order to produce only 72 volts. This means that the vehicle can utilize the existing controller. Moreover, a 24 volt battery pack was added to the front part of the car. This battery pre-charges the field winding of the motor, causing the motor to have more startup torque.

Cost:

Six additional Johnson Controls deep cycle 12 volt batteries were in conjunction with the already existing Trojan batteries in order to minimize cost. Also, a 24 volt pack battery was added to help the car move and overcome inclines. For the final cost analysis, click here

Speed:

By adding the batteries, the weight of the car increased and had a negative effect on speed. However, by adding the 24 volt battery pack, the motor was provided with more voltage causing an overall increase in the speed. The top speed of the vehicle is now 68 mph.

Range:

Range was increased with the addition of 6 more batteries connected in a series/parallel configuration. This effectively doubled the capacity of the battery pack. However, due to the increased weight, range was not exactly doubled. We saw in increase in range from about 30 miles to about 50 miles, depending on how fast you drive.

Achieve inclines:

The addition of a 24 volt field battery pack wired directly to the field windings on the motor solves the problem of initial startup torque. The car now has all the torque it needs to start from a dead stop on a hill without problem.