Mechanism-Resolved Effects of Battery Capacity Reduction and Resistance Scaling on Electric Vehicle Range and Energy: A Same-VIN Nissan LEAF Case Study

Battery capacity and resistance affect different vehicle responses, and their apparent importance depends on the range criterion. This study compares these effects in a fixed 2011 Nissan LEAF ZE0 model using measurements linked to the same vehicle identification number (VIN). Beginning-of-test (BOT) and end-of-test (EOT) pack measurements define controlled capacity-only, resistance-only, and coupled states. Under repeated Worldwide Harmonized Light Vehicles Test Cycle (WLTC) operation from 100% to 20% state of charge (SOC), replacing the rated pack capacity of 66.2 Ah with the measured BOT capacity of 57.6 Ah reduced the simulated distance from 113.59 to 100.48 km (−11.54%). BOT resistance scaling alone yielded 113.42 km (−0.15%); the coupled state yielded 100.02 km (−11.95%). The 66.2- Ah rating is not a measured beginning-of-life capacity, so these differences are nominal reference simulation contrasts, not measured lifetime range losses. Capacity dominance is expected under the SOC stopping rule. Resistance scaling was more visible in the diagnostic integral of current squared times effective resistance (I2R): BOT increases were 12.34% under WLTC and 13.01% under the US06 supplemental driving schedule, while terminal energy changes were −0.10% and <0.01%, respectively. Under the severe EOT resistance sensitivity, these diagnostic increases reached 197.27% and 231.12%, and the US06 operational minimum battery terminal voltage fell from 360.84 to 277.55 V. The contribution is a controlled comparison of range, terminal energy, voltage, and resistance-sensitive diagnostics. Numerical effect sizes apply to the tested model and boundaries; voltage-, power-, and temperature-limited operation require separate evaluation.