How this calculator works
It estimates two things: what a charging session costs to run, and a transparent range for installing the charging point. The running cost uses your battery size, the charge level you top up from and to, your tariff, and how many sessions you do a month:
- Energy into the battery = battery kWh × (target % − current %) ÷ 100.
- Energy drawn from the wall = energy into the battery ÷ 0.9 (about 90% AC charging efficiency — some energy is lost as heat).
- Cost per session = energy from the wall × your tariff (₹/kWh); monthly = per session × sessions/month; annual = monthly × 12.
- Installation range = charger + cabling (per metre) + optional civil work and sub-meter, from editable, clearly-labelled sample assumptions — never a quote.
Worked example. A 30 kWh car charged 20%→80% needs 18 kWh into the battery, about 20 kWh from the wall; at ₹8/kWh that is roughly ₹160 a session, and about ₹1,280 a month over 8 sessions. These are estimates — confirm your tariff with your DISCOM and get a written installer quote.
Common questions
Is this an official installation quote?
No. It is an estimate built from your inputs and clearly labelled sample assumptions. Get a written quotation and a site inspection from a licensed electrician or authorised installer before you commit.
What tariff should I enter?
Use the per-unit energy charge (₹ per kWh) from your electricity bill, at the slab your total consumption falls in. Adding charging can push you into a higher slab, which raises the marginal rate.
Does the estimate include installation cost?
Yes, shown separately. Alongside the running cost it gives an installation cost range built from editable sample assumptions for the charger, cabling, civil work and metering. Real installer quotes will differ.
Why is "energy from the wall" higher than the energy added to the battery?
AC charging loses some energy as heat, so the meter records a little more than reaches the battery. The calculator assumes about 90% charging efficiency.
Who this tool is for
Apartment residents budgeting for a private charging point, and RWA committees comparing what different charger types cost to run. For billing models for shared chargers, see our billing and metering guides.