Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)


Agricultural Engineering


Development of test procedures and the accumulation of test data are essential for the proper design of agricultural electric vehicles (EVs). Electric Choremaster I is a research prototype that applies the advantages of EV technology to farm chore tasks. Design and construction of this tractor were completed in June 1984. Life-cycle economic savings plus demonstrated EV advantages of low noise, absence of noxious fumes and ease of starting were expected to favor EVs for farm chore tasks. Many battery-powered vehicles were in use at the beginning of this century. However, due to their limited range, they were replaced by internal-combustion engine vehicles for all but specialized applications. The energy crisis in the 1970s rekindled public interest in general-purpose EVs. Although that public interest has waned in the wake of the present "oil glut", the quantity and diversity of EVs sold has grown as industries capitalize on the advantages of such vehicles for specialty applications. Continued expansion of EV use would help reduce the vulnerability of the United States to another energy crisis. Similarly, electric tractor development would help reduce the vulnerability of agriculture to a sudden slowdown or interruption of oil supplies. The Department of Energy sponsored studies at several land-grant universities to determine the feasibility of battery-powered tractors. The results of a study at South Dakota State University (SDSU) indicated that an electric tractor could do many chore tasks on North Central United States farms to liquid fuel work, but these researchers determined that this would not be a limiting factor for specialized chore work. Less noise, no fumes and lower repair cost were cited as advantages. The National Rural Electric Cooperative Association and the SDSU Agricultural Experiment Station financed the conversion of a four-wheel drive, articulated diesel tractor to battery-power, which resulted in the EC-I. The first prototype was designed and built, but the limited availability of design information to size the EV components meant that testing was ·crucial to evaluate component sizing. Extensive testing of the prototype was, therefore, necessary to obtain important information to help design future electric tractors. Testing provided a more exact method of predicting energy use to help size batteries and motors for specific agricultural tasks. The main goal of testing ·was to determine the operating characteristics of the prototype EC-I, thereby, providing information for design improvements and for design of future agricultural EVs. The following four objectives were defined to achieve this goal: 1. Devise a test procedure to quantify battery powered farm tractor performance. 2. Determine power take-off and drawbar power maximums and related operating characteristics. 3. Develop a model that calculates EC-I energy use for farm chore tasks by summing the predicted energy requirements for standard task segments, and evaluate the model using an independent data set. 4. Recommend design improvements for the EC-I prototype.

Library of Congress Subject Headings

Tractors -- Design and construction -- Testing



Number of Pages



South Dakota State University


No Copyright - United State