The cheapest car is the one with the lower total cost for your mileage, charging access, finance and ownership period—not the one with the cheapest fuel headline. Build two like-for-like five-year cash-flow models and run a no-incentive case before deciding.
Which car-cost model should you use?
Pick the one path that matches your charging reality.
Path A — Reliable home charging
Model most charging at your actual residential tariff, then add a smaller public-fast-charging share. Include charger installation and any electrical-upgrade cost.
Path B — Mixed home and public charging
Use a weighted electricity price: home kWh × home share plus public kWh × public share. Stress-test the result if the public-charging share grows.
Path C — Mostly public charging
Use your real nearby network prices and detour/time costs. Do not use a low home tariff if you cannot realistically charge at home.
Path D — Incentive-dependent purchase
Run two cases: incentive received and incentive not received or delayed. A purchase should not look affordable only because an unapproved subsidy was assumed.
The five-year formula that prevents misleading comparisons
Use the same ownership period and annual distance for both cars. Compare cash actually paid, not just fuel versus electricity.
For an EV, add home-charger installation or sanctioned-load upgrades. For a petrol car, use realistic city/highway fuel efficiency from your use case rather than a brochure number. For both, model insurance renewal and finance on like-for-like assumptions.
Build the energy-cost comparison from your own usage
| Input | EV calculation | Petrol calculation |
|---|---|---|
| Annual distance | Your km/year | Same km/year |
| Efficiency | Measured or credible kWh per km | Measured or credible km per litre |
| Energy price | Weighted ₹/kWh across home and public charging | ₹/litre for the fuel actually used |
| Annual energy cost | km × kWh/km × weighted ₹/kWh | km ÷ km/litre × ₹/litre |
Worked example: use the method, not the numbers
Suppose you drive 12,000 km a year. EV A consumes an illustrative 0.15 kWh/km and your weighted charging price is an illustrative ₹10/kWh. Energy cost would be 12,000 × 0.15 × 10 = ₹18,000 a year. Petrol Car B delivers an illustrative 14 km/litre and fuel is assumed at ₹100/litre, giving 12,000 ÷ 14 × 100 ≈ ₹85,714 a year.
Those figures are example inputs, not market claims. Replace every number with your own tariff, public-charging mix, actual fuel price and expected efficiency. Then compare annual energy saving with upfront price, finance, insurance, charger cost and expected resale. The answer can reverse when mileage or charging access changes.
Separate battery risk from an unsupported full-replacement estimate
Read the exact battery warranty for the model: years, kilometres, any capacity threshold, exclusions, transferability and claim process. If your planned ownership ends inside a strong transferable warranty, automatically inserting a full battery replacement can overstate expected cost. If you plan to own well beyond warranty, model a downside reserve or lower resale value rather than pretending battery risk is zero.
Separate routine degradation from a rare major failure. Ask for battery-health information when buying used, and price uncertainty instead of inserting an arbitrary replacement every five years.
Break-even matters only if you keep the car that long
Calculate the EV’s extra upfront and financing cost after confirmed incentives. Divide that by expected annual operating saving for a simple break-even estimate. Then compare that period with how long you realistically keep cars.
- Run low-, base- and high-mileage cases.
- Run home-charging and mostly-public-charging cases if your housing situation may change.
- Keep incentives at zero until eligibility and approval are verified.
- Use a conservative resale range rather than one optimistic number.
- Compare monthly cash flow as well as five-year total cost.
Official sources
- PM E-DRIVE official portal
- PM E-DRIVE policy and procedure
- PM E-DRIVE approved model details — official model-level range, energy-consumption, warranty and battery specifications.