[Car Tips] How many kilometers can an electric car travel per kilowatt-hour? How to calculate power consumption

The following uses the most common "kilowatt-hour = 1 kWh" to explain.

1. Quick answer: How many kilometers can an electric car travel on one kilowatt-hour of electricity?

• Most modern electric cars: about 4–8 km/kWh
• High-efficiency small cars, urban slow speeds: up to 8-10 km/h
• Large/high-performance cars or high-speed cruising: 3–5 km/°C is common

The key differences lie in vehicle type, speed, temperature, tires and air conditioning use.

2. How can I calculate it most accurately?

• Known power consumption (kWh/100km) → Convert km/kWh:
  • km/degree= 100 ÷ (kWh/100km)
  • Example: 16 kWh/100km → 100 ÷ 16 = 6.25 km/degree
• Known meter display (Wh/km) → Convert km/degree:
  • km/degree= 1000 ÷ (Wh/km)
  • Example: 180 Wh/km → 1000 ÷ 180 ≈ 5.56 km/degree
• Estimated battery life on a full charge:
  • Endurance ≈ Available power (kWh) × km/kWh
  • Example: Available electricity 60 kWh, efficiency 6.25 km/kWh → approximately 375 km
• Electricity cost per 100 km:
  • Cost/100km = (kWh/100km) × electricity price
  • Example: 16 kWh/100km, household electricity price 3 yuan/kWh → 48 yuan/100km
  • If it is a public fast charging 12 yuan/kWh → 192 yuan/100km

3. Common power consumption ranges for different levels (practical reference)

• Small hatchback/city car: 11–15 kWh/100km → 6.7–9.1 km/kWh
• Mid-size sedan/SUV: 14–18 kWh/100km → 5.6–7.1 km/kWh
• Mid-to-large SUVs: 18–24 kWh/100km → 4.2–5.6 km/kWh
• Large/high performance: 22–30 kWh/100km → 3.3–4.5 km/kWh
• City driving vs. highway driving: City driving is generally more energy-efficient (more recharging, lower speed); highway driving (110–120 km/h) consumes significantly more power due to significant wind resistance.

4. List of main factors affecting electric vehicle power consumption

• Vehicle speed and wind resistance: Wind resistance increases with the square of speed, and the required power increases approximately with the cube of speed; high speed consumes the most power.
• Temperature and air conditioning:
  • Low temperature: Battery internal resistance increases, the car is heated and the cabin heater consumes energy, with power consumption of +10–40% common; heat pump vehicles are more economical.
  • High temperature: cooling energy consumption, +5–15% is common.
  • Pre-conditioning (connecting the power supply to pre-cool/pre-heat before departure) can reduce energy consumption during driving.
• Terrain and slope: Uphill driving consumes more energy, while downhill driving allows for recharging. Recharging is limited when the battery is too cold, fully charged, or on long downhill slopes.
• Tires and tire pressure: Low tire pressure, wide tires/performance tires, rough roads → increased rolling resistance and increased power consumption.
• Load and external attachments: A fully loaded vehicle with a roof rack or roof box significantly increases wind resistance and energy consumption.
• Weather conditions: headwind, rain, snow and wet ground → increased energy consumption (rolling resistance and wind resistance).
• Driving habits: sudden acceleration, sudden braking, and following too close a distance (frequent gear changes) all reduce efficiency; ECO/single-pedal gliding is more economical.
• Vehicle design: drag coefficient, frontal area, drive architecture (two-wheel drive vs. four-wheel drive), heat pump and battery thermal management efficiency.
• Wheel size and aerodynamic kit: Large open rims have higher wind resistance.
• Other electrical appliances: defogger, seat heating, audio and video, etc. are mostly small heads, but the proportion will be magnified in low-speed short distances.

5. Simple method to measure your car's "real km/deg"

• On the same route and in the same temperature range, reset the trip meter and drive 50–100 km, recording Wh/km or kWh/100km.
• Measure the city and highway driving (90/110/120 km/h) to establish your speed-power consumption curve.
• Measure once in winter and once in summer to get the seasonal coefficient (usually +15–30% more in winter, depending on the car model and climate).

6. Commonly used quick conversions

• 150 Wh/km → 6.7 km/degree
• 180 Wh/km → 5.6 km/degree
• 200 Wh/km → 5.0 km/degree
• 250 Wh/km → 4.0 km/degree
• 12 kWh/100km → 8.3 km/degree
• 16 kWh/100km → 6.25 km/degree
• 20 kWh/100km → 5.0 km/degree
• 25 kWh/100km → 4.0 km/degree

7. Cost Comparison Example (For illustration only, please substitute your actual electricity/oil price)

• EV: 16 kWh/100km
  • Home charging: 3 yuan/kWh → 48 yuan/100km
  • Public fast charging: 12 yuan/kWh → 192 yuan/100km
• Gasoline car: Fuel consumption 12 km/L, fuel price 30 yuan/L → 250 yuan/100km

8. Differences in testing standards (tips for reading catalog data)

• For the same vehicle, EPA is generally the most conservative, WLTP is the second most conservative, and CLTC is the most optimistic. For example, for range, CLTC can be 20–35% higher than EPA. When converting to power consumption, CLTC's "apparent power consumption" often appears lower. For conservative estimates, consider EPA or even discount WLTP.

If you provide your car model, road conditions (ratio of urban to highway), local temperature and charging rates, I can calculate a more realistic km/kWh, range and cost per kilometer for you.

Editor's opinion

• Three-sentence summary

  • How far you can travel on one kilowatt-hour of electricity is most affected by vehicle speed and temperature, followed by vehicle type and tires.
  • Don't be fooled by the most optimistic data when looking at catalogs; the key is to grasp "your own Wh/km".
  • The most effective way to save electricity is not to spend money on modifications, but to develop the habit of steady speed and pre-adjustment.

• Practical car selection/equipment suggestions

  • Heat pump air conditioner: People in cold areas or those who frequently commute in the morning and evening will feel the benefits; it can save double-digit percentages of energy in winter.
  • Tires prioritize "low rolling resistance" over width and performance; large-size rims are mostly just for looks.
  • Two-wheel drive vs. four-wheel drive: Two-wheel drive is more energy-efficient and cheaper in most road environments; four-wheel drive is only used if traction/mountain road grip is really needed.
  • Wind resistance is king: SUVs are stylish, but they inherently consume less energy. If you frequently drive on national highways, avoid high-drag roof boxes or racks if possible.

• Everyday energy-saving tips (free of charge)

  • The high-speed constant speed is 100–110 km/h, which usually saves 10–20% of power compared to 120–130 km/h.
  • Maintaining tire pressure at the upper limit of the factory recommendation or +2-3 psi for cold tires will provide more balanced rolling resistance and wear.
  • Connect the power supply for pre-cooling/pre-heating before departure. In winter, make good use of the steering wheel/seat heating and use the high-volume heater less often.
  • Less sudden acceleration and braking, and early coasting; more short distances, single-pedal/ECO mode is very popular.
  • Avoid starting with a full charge before a long downhill slope to leave room for recharging; otherwise, kinetic energy recovery will be limited and the braking burden will be heavy.

• Cost and Charging Strategy

  • Home slow charging is the most economical, with the cost per 100 kilometers usually ranging from 1/3 to 1/5 of the fuel cost; fast charging mainly buys time.
  • Don't forget charging losses: AC charging costs are about 5–12%, and DC charging costs are about 10–15% (depending on the vehicle model and charging station). It's more practical to calculate costs based on the number of kilowatt-hours charged.
  • After fast charging to 80%, the power generally drops sharply and the cost/kilometer increases; for long-distance travel, "multiple 10-70/80%" fast charging is more efficient.
  • If electricity prices are time-of-use, try to charge during off-peak hours; public fast charging in Taiwan typically costs NT$8-15 per kWh, and residential fast charging costs are around NT$2.6-4.5 per kWh (depending on the tier/plan).

• How to read your own data

  • The Wh/km meter shows "driving electricity usage," which is less the charging losses than the kilowatt-hours you put in from the meter. To calculate the cost, use the kWh from the charging station/meter.
  • Establish a "seasonal factor": summer baseline, +15–30% in winter is common; varies greatly from car to car.
  • Measure the speed curve yourself: run 30-50 kilometers at 90/110/120 km/h for each speed for comparison. This will make long-distance estimates more accurate in the future.

• Common Myths and Clarifications

  • "Can recharge offset the energy consumption of going uphill?" No. Recharge efficiency is limited, usually around 60-80%. It can restore some health, but it's not a perpetual motion machine.
  • "Does a larger battery always save energy?" Not necessarily. It's heavier and consumes more power, but it can reduce the number of deep cycles and fast charges. It all depends on your vehicle's usage.
  • Is the car's range not up to par? It's likely due to different operating conditions. Try running the same route and temperature a few times before drawing conclusions.

• Second-hand and battery health

  • It is normal for most mainstream batteries to degrade by about 5-10% in the first 50,000-80,000 kilometers; heavy fast charging, long-term high SoC or high temperature exposure will accelerate degradation.
  • When looking at used cars, first ask for the BMS available capacity, charging habit records, and charge and discharge mileage structure (highway/urban).

If you provide your car model, typical speed/mileage, climate, and charging conditions, I can provide you with "recommended tire pressure, ideal cruising speed, summer/winter km/degree estimates," and an annual cost budget based on your situation.