How Charging Cost Is Calculated

Formula: Charging Cost = Battery Capacity (kWh) × Tariff (₹/kWh) × Loss Factor (typically 1.10–1.15)

Example: A 40 kWh battery charged at ₹8/kWh with a 10% loss factor: 40 × ₹8 × 1.10 = ₹352 for a full charge. Over a 250 km range, that’s roughly ₹1.40/km.

Home Charging: The Cheapest Option

Most EV owners do 80–90% of charging at home. Domestic tariffs generally range from ₹4 to ₹10 per kWh, depending on state and DISCOM.

Battery Size	Tariff	Full-Charge Cost
25–30 kWh	₹6/kWh	₹165 – ₹200
40 kWh	₹8/kWh	₹350 – ₹380
50–60 kWh	₹9/kWh	₹500 – ₹600

Two things worth knowing: most states use slab-based tariffs, so adding EV charging load can push you into a higher slab, and some DISCOMs now offer dedicated EV meters/tariffs that keep charging costs separate from your household bill.

Public Charging: Faster, Pricier

Public operators price higher to cover infrastructure, maintenance, and service margins.

Charger Type	Typical Rate
Public AC	₹8 – ₹15/kWh
Public DC fast	₹15 – ₹25/kWh
Premium/highway DC	₹20 – ₹25+/kWh

A 40 kWh charge at ₹20/kWh public DC runs close to ₹880 — more than double the home-charging equivalent. You’re paying for speed, which makes sense for long trips but not routine daily use.

EV vs Petrol: The Real Comparison

Metric	EV (Home Charging)	Petrol
Cost per km	₹0.60 – ₹1.50	₹5 – ₹7
Cost per 1,000 km	₹600 – ₹1,500	₹5,000 – ₹7,000

Even factoring in occasional public fast charging for long trips, EVs typically stay well below petrol on cost per kilometre — often by 5x or more.

What Changes Your Actual Cost

• State tariff structure — slab-based pricing in states like Maharashtra, Tamil Nadu, and Delhi means your rate depends on total monthly usage
• Battery size and vehicle efficiency — km per kWh matters more than absolute battery size
• Charging losses — older equipment can exceed the standard 10–15% assumption
• AC vs DC mix — heavier reliance on public DC fast charging raises your average cost per km
• Time of charging — off-peak charging is cheaper where time-of-day tariffs apply

Tips to Lower Your Charging Cost

• Charge at home whenever possible — it’s consistently the cheapest option
• Check if your DISCOM offers a dedicated EV tariff or meter
• Use smart charger scheduling to shift charging to off-peak hours
• Reserve public DC fast charging for long trips or emergencies
• Consider rooftop solar if you own your property
• Track your actual efficiency rather than relying on manufacturer claims

Common Mistakes

• Defaulting to public fast charging for routine daily top-ups
• Assuming a flat per-unit rate and ignoring slab-based pricing
• Not checking for a dedicated EV connection where available
• Overlooking charging losses when estimating monthly cost

Home vs Public Charging

Home Charging	Public Charging
Lowest cost per kWh	Fast — ideal for long trips
Convenient overnight routine	No home charger investment needed
Requires upfront installation cost	Higher per-kWh rate
Not always available for apartment dwellers	Availability varies by location

Key Takeaways

• Home charging: ₹4–10/kWh; public charging: ₹8–25/kWh depending on AC or DC
• A mid-size EV’s full home charge typically costs ₹300–400; public DC fast charging can cost double
• EVs run at ₹0.60–1.50/km at home versus ₹5–7/km for petrol
• Tariff slabs, charging losses, and AC/DC mix all affect your real cost per km

Conclusion

Home charging is cheap and convenient for daily use; public charging costs more but buys speed when you need it. Once you understand your state’s tariff structure and your vehicle’s real-world efficiency, EVs consistently beat petrol on running cost — often by a wide margin, especially the more you rely on home charging.