Charging an EV with Rooftop Solar in India

Short answer: to cover home EV charging with solar, add about 1–1.5 kW of rooftop solar per 1,000 km a month for a typical electric car, and about 0.2–0.3 kW for an electric scooter, depending on your vehicle and city. Under net metering you can charge at night using units banked during the day. Check your sanctioned load before adding a 7 kW charger.

Step 1: how many units does your EV use?

The car's trip computer shows energy use in kWh per 100 km (or Wh/km). Typical Indian figures:

Add charging losses of about 10% (AC charger and on-board charger).

Step 2: convert units to kW of solar

Extra solar (kW) = monthly EV units × 12 ÷ city yield

Yields in kWh/kWp/yr from Global Solar Atlas, derated 5% for rooftops (Sunlectric Studio data).

So a home using 300 units plus 150 units of EV charging should size for about 450 units a month. See solar for 500 units for that range.

Day charging vs night charging

• Night charging with net metering: your solar exports during the day, and you import at night. Over the settlement period, imports and exports net off. Simple, and you charge when the car is home.
• Daytime charging: if the car is home at noon (work from home, second car), charging directly from solar avoids any question about ToD rates and banking slots.
• With a battery: possible but expensive; a car battery is much bigger than a home battery, so a home battery can only top it up.

Watch the ToD rules

Time-of-day tariffs make solar-hour units cheaper and evening peak units dearer. If your state banks units slot by slot (common for non-residential consumers), daytime solar may not offset night charging fully. Check how your DISCOM settles. Some DISCOMs offer a separate EV tariff, sometimes cheaper at night.

Load and wiring

• A 3.3 kW portable charger draws about 14 A on single phase. A 7.2–7.4 kW wall box draws about 32 A, which can strain a 5 kW sanctioned single-phase connection with ACs running.
• Get the sanctioned load enhanced if needed; it is often required anyway when adding solar above the current load.
• The charger should have its own circuit with an appropriate MCB and RCD as recommended by the charger maker, and proper earthing.
• If your inverter is single-phase and the house is three-phase, plan which phase the charger sits on.

The subsidy angle

• Homes: the PM Surya Ghar subsidy is capped at ₹78,000, reached at 3 kW (check current notification). Adding 1.5 kW for the car earns no extra central subsidy, but the extra kW costs less per kW as the system grows.
• Housing societies: common-facility systems get ₹18,000 per kW, and the scheme explicitly includes EV charging among common facilities. See solar for housing societies.

Is it worth it?

Charging an EV from grid power at ₹8–15 per unit is already cheaper per km than petrol. Covering those units with solar at a lifetime cost of roughly ₹2–3 per unit (system price spread over 25 years of output, before subsidy) cuts the running cost further. Test your case:

Practical tips

• Plan for the next 5 years: a second EV or a switch from scooter to car changes your size.
• Keep roof space for expansion, and pick an inverter with headroom or plan a second inverter.
• Use the car app's scheduled charging to start after a certain hour if your ToD tariff rewards it.

Example: a Pune family adding an electric car

• Home use today: 300 units a month
• New car: about 1,000 km a month at roughly 15 kWh per 100 km, plus 10% charging losses ≈ 165 units a month
• New total: about 465 units a month, or 5,580 units a year
• Pune yield: 1,513 units per kW per year → 5,580 ÷ 1,513 ≈ 3.7 kW

So instead of the usual 3 kW for 300 units, this family should plan about 4 kW. The central subsidy stays at ₹78,000, and the extra kW costs less per kW than the first three.

Electric scooters

A scooter that runs 1,000 km a month at about 3 kWh per 100 km needs only about 30–35 units a month including losses. That is roughly 0.25 kW of extra panels, often already covered by the headroom in a well-sized home system.

Checklist before you add a charger

• Confirm sanctioned load and phase can take the charger plus your normal peak
• Put the charger on its own circuit with protection as the charger maker specifies
• Keep the charger out of direct rain or use an outdoor-rated unit
• Ask your DISCOM whether an EV tariff or separate EV connection is cheaper for you

Talk to Sunlectric

Buying an EV and want to size solar for it? WhatsApp your bill, your car model and monthly kilometres to +91 89567 89307 (wa.me/918956789307). Our Solar Desk will work out the extra kW, and our installer network can add solar and the charger circuit together.

Sources

• PM Surya Ghar CFA, including RWA/GHS EV charging: pmsuryaghar.gov.in; PIB, Aug 2024 (accessed Oct 2026)
• Separate EV connections under Rights of Consumers Rules: SolarQuarter, 23 Feb 2024
• ToD tariffs: Indian Infrastructure, 21 Jun 2023
• City yields: Global Solar Atlas, fetched 19 Oct 2026
• EV consumption ranges are typical values; check your vehicle's trip data