UHM/HNEI EV test and evaluation program

Abstract

The electric vehicle (EV) program of the Hawaii Natural Energy Institute (HNEI) focuses primarily on the field testing of promising EV/traction batteries. The intent is to utilize typical driving cycles to develop information that verifies or refutes what is obtained in the laboratory. Three different types of battery were assigned by the US DOE for testing in this program: Sonnenschein Dryfit 6V-160, Exide GC-5, Trojan T-145. We added the following battery to the test program: ALCO2200. HNEI's existing EVs were utilized as test beds. The following EVs were chosen in our program: Converted Ford Escort station wagon, Converted Ford Escort two-door sedan, Converted Ford Escort two-door sedan, Converted Dodge van (typically daily driving distances, 10--30 miles). Capacity testing is a very effective way of monitoring the status of battery modules. Based on capacity tests, corrective action such as battery replacement, additional charging, adjusting terminal connections, etc., may be taken to maintain good performance. About 15,500 miles and 600 cycles have been accumulated on the Sonnenschein Dryfit 6V-160 battery pack. Five of its 18 modules have been changed. Based on DOE's standard, the battery has reached the end of its useful life. Nevertheless, the battery pack is still operational and its operating range is still greater than 40 miles per charge. It is too early to evaluate the life expectancy of the other three batteries, the Trojan T-145, Exide GC-5, and Alco 2200. No module has been replaced in these three packs. The Trojan T-145 battery is a very promising EV traction battery in terms of quality and reliability versus price. HNEI will keep the Trojan and Exide battery packs in operation. The Alco 2200 batteries will be transferred to another vehicle. The Additional Charging Method seems to be an effective way of restoring weak modules. The Smart Voltmeter'' developed by HNEI is a promising way of monitoring the remaining range for an EV.