EV Charging Load Calculator — Extra Solar & Charger Size for 2026

Adding an EV changes your energy math. See the extra daily energy, panels and charger size you'll need.

⏱ ~15 sec🚗 Any EV/mileage🔒 No signup
18 is typical for a mid-size EV; small EVs ~15, SUVs ~22

What the EV adds

7.4 kWh/day
Extra daily charging energy
Extra panel capacity needed1.9 kW
Extra panels (450W)5
Extra system cost$5,320
Daily charge time needed1.2 hrs

Charge time assumes charging at your selected charger's full power — actual time may be longer at low battery temperatures or with slower onboard chargers.

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How EV charging load is calculated

Daily energy (kWh) = (Annual km ÷ 100) × Efficiency (kWh/100km) ÷ 365 ÷ Charging efficiency
Extra panel capacity (kW) = Daily energy ÷ (Sun hours × 0.8)
Daily charge time (hrs) = Daily energy ÷ Charger power

Charging losses (heat in the cable, the car's onboard AC-to-DC converter, battery chemistry) typically waste 8-12% of the energy you pull from the wall, which is why the daily energy figure is slightly higher than "distance × efficiency" alone.

EV charger electrical load calculation (panel/circuit sizing)

This tool answers "how much solar do I need for my EV" — a separate but related question is the load calculation for EV charger circuits (also written as EV charger electrical load calculation): whether your home's electrical panel and the circuit feeding the charger can safely handle it, independent of solar. That's a code-driven calculation, not a solar-sizing one:

Continuous load rule (NEC 625/220): Breaker & circuit ampacity ≥ 1.25 × Charger's rated current
Example: a 40A-rated Level 2 charger needs a 50A breaker on a 50A-rated circuit

Because EV charging is classified as a continuous load (running 3+ hours at a stretch), electrical code requires the breaker and wiring to be sized at 125% of the charger's rated draw, not just matched to it — this is separate from whatever "load calculation" a solar installer runs to size panels. If you're also adding solar and considering a service upgrade, an electrician performing a whole-panel load calculation (NEC 220.83, load-summing all your existing circuits plus the new EV circuit) will determine whether your existing service size supports both the charger and any planned solar/battery equipment without an upgrade. Always confirm exact requirements with a licensed electrician for your specific panel and local code.

Frequently asked questions

Should I size solar for the EV even if I mostly charge overnight?

If you're off-grid or want to charge from solar directly during the day, size for it. If you're grid-tied with net metering, your exported daytime solar and nighttime EV charging can net out over the billing period even without extra panels — check the Net Metering Calculator.

Do I need extra battery for the EV too?

Only if you want to charge the car from stored solar after dark without touching the grid — otherwise the EV's own battery is the "storage." Use the Battery Size Calculator if you're planning whole-home storage anyway.

What is the load calculation for an EV charger?

It's the electrical-code check (not a solar-energy calculation) confirming your breaker, wiring and main panel can handle the charger's continuous draw — typically requiring circuit ampacity at 125% of the charger's rated current, per NEC 625 and 220 rules. A licensed electrician should confirm this before installation.

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