Electric vehicle range is affected by altitude primarily through air density changes and elevation-driven energy demands:
1. Air Density and Aerodynamics
Lower air density at higher altitudes reduces aerodynamic drag, improving efficiency. This is particularly beneficial on flat terrain or gradual slopes. However, this advantage is often offset by elevation-related energy demands.
2. Elevation Changes and Energy Use
- Climbing: Inclines require significant energy, with losses proportional to elevation gain. For example, ascending a 5,338′ pass (like Summit, MT) would consume more power than flat terrain, though exact losses depend on grade and speed.
- Descending: Regenerative braking recovers energy, reducing net losses if elevation loss offsets gains. A net elevation drop (e.g., Missoula to Lethbridge’s 200′ net descent) could slightly improve range, assuming mindful driving to maximize regen.
- Net Effect: Real-world data suggests a ~5% range impact for routes with elevation changes when gains and losses balance out.
3. Route-Specific Considerations
For the Missoula-to-Lethbridge route (with a net elevation drop and one major pass):
- Uphill Segment: The Summit, MT pass (5,338′) will temporarily reduce range due to energy-intensive climbing.
- Downhill Segment: Regenerative braking on descents compensates partially, especially in “high summer months” with no snow.
- Outcome: The net 200′ drop suggests minor overall impact, but the pass may require conservative speed/acceleration to avoid excessive drain.
Rule of Thumb
- Moderate elevation changes: ~5% range impact if elevation gains and losses are balanced.
- Net elevation loss: Slight range benefit, assuming efficient regen use.
- Critical factors: Speed, HVAC use, and regenerative braking efficiency dominate over altitude alone.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/how-does-altitude-affect-ev-range/
