Electric Vehicles: Impacts of Mileage Accumulation and Fast Charging

The impact of mileage accumulation and fast charging on driving range and battery energy of a light-duty battery electric vehicle (BEV), commercially available in North America, is being investigated. Two identical model BEVs are undergoing mileage accumulation on-road in Ottawa, Canada as well as testing on a chassis dynamometer in accordance with the SAE J1634 recommended test procedures. BEV1 is charged exclusively on DC fast-charging (DCFC) and BEV2 is charged exclusively on SAE AC Level 2 (ACL2). At the time of writing, the BEVs have been tested initially at 1,600 km, and then again after mileage accumulation to 15,000 km. Baseline results indicate that the two BEVs had a similar initial performance, and after 15,000 km the vehicles continue to have a similar driving range and useable battery energy despite the different charging methods. Both vehicles did, however, show decreased useable battery energy and recharge energy after 15,000 km of mileage accumulation and the resulting decrease in driving range varied between 0.4 and 13% depending on test conditions; these changes were not always statistically significant. Further testing is planned at approximately 15,000 km intervals up to 105,000 km. The next round of testing, at 34,000 km, will follow mileage accumulation at cold temperature, during an Ottawa, Canada winter.