Energy
What it really costs to charge an electric car at home
Three numbers decide your running cost: the electricity price, the car's efficiency and charging losses.
Charging isn't perfectly efficient. Some energy is lost as heat in the charger and battery, often around 10% for home charging, and sometimes more when charging slowly from a standard power point. So the energy you pay for is a bit more than what the battery receives.
Worked example
| Item | Calculation | Result |
|---|---|---|
| Energy added | 60 kWh × (80% − 20%) | 36 kWh |
| Energy from the grid | 36 ÷ 0.9 | 40 kWh |
| Cost at 30c/kWh | 40 × $0.30 | $12.00 |
| Range added at 16 kWh/100 km | 36 ÷ 16 × 100 | ≈ 225 km |
| Cost per 100 km | 16 ÷ 0.9 × $0.30 | ≈ $5.33 |
| Petrol car, 7 L/100 km at $1.95 | 7 × 1.95 | $13.65 |
Ways to cut the cost
1
Charge off-peak or on solar
Time-of-use and EV tariffs can make overnight power much cheaper, and charging from your own panels during the day avoids grid prices.
2
Check your real efficiency
Highway driving, heating or cooling, and cold weather all raise kWh/100 km. Use the trip computer's average.
3
Keep daily charging between about 20% and 80%
Many manufacturers suggest this range for everyday use. Check your car's manual.
💡 Pro Tip: Have a licensed electrician check your switchboard and circuit before you install a wall charger.
✨ Key Takeaways
- Grid energy = battery energy ÷ (1 − losses).
- Cost per 100 km = kWh/100 km ÷ (1 − losses) × price.
- Off-peak and solar charging change the numbers a lot.
Open the EV charging cost calculator →
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