EV-Solar Calculator: Estimate Your EV Charging Savings with Solar

EV-Solar Calculator for Homeowners: Optimize Panels, Battery, and Charging

What it does

An EV-solar calculator for homeowners estimates how to meet electric vehicle charging needs using rooftop solar plus optional battery storage. It models energy flows (solar generation → home loads → EV charging → battery → grid) and outputs system sizing, costs, savings, emissions, and payback.

Key inputs (typical)

• Location (solar resource)
• Home electricity use (daily kWh)
• EV charging needs (miles driven per day, vehicle efficiency in kWh/mi)
• Solar system details (panel kW, production profile, tilt)
• Battery (usable kWh, round-trip efficiency, max charge/discharge rate)
• Electric rates (time-of-use or flat), net metering rules, incentives/rebates
• Charger type (Level ⁄₂, charging power, charging schedule)
• Installer & equipment costs, operation & maintenance, inflation/discount rate

Outputs to expect

• Recommended solar panel size (kW) and expected annual generation
• Battery size (kWh) needed to shift solar to evening/night charging or increase self-consumption
• Fraction of EV charging met by solar (daily/annual %)
• Grid electricity imported/exported and net energy cost per year
• Upfront cost, incentives applied, annual savings, simple payback and discounted payback
• CO2 emissions avoided (if grid emission factor provided)
• Charging schedule optimization to maximize solar use or minimize cost under TOU rates

Useful features

• Hourly or subhourly simulation for accuracy with TOU rates and charging windows
• Sensitivity analysis (vary miles driven, battery costs, panel prices)
• Scenario comparison table: solar-only, solar + battery, grid-only charging
• Exportable summary (PDF) and detailed CSV of hourly flows
• Local incentives and installer cost estimates (location-aware)

Practical guidance for homeowners

• If you drive <30 miles/day, a modest solar array (~3–5 kW) often covers most EV charging in sunny regions.
• Batteries are valuable when you need evening charging with low net-metering credits or under TOU pricing; otherwise, larger panels plus daytime charging may suffice.
• Maximize self-consumption by scheduling charging during peak solar hours or using simple smart charging.
• Always include realistic system losses (inverter, temperature, battery inefficiency) and conservative production estimates.

Simple example (assumed defaults)

• Home + EV needs: 25 miles/day × 0.34 kWh/mi = 8.5 kWh/day for EV
• Solar: 4 kW array producing ~16 kWh/day average → could cover EV and some home load on sunny days
• Battery: 10 kWh usable increases solar fraction for night charging but adds cost; evaluate payback under local rates

If you want, I can produce a one-page calculator (inputs, formulas, and example Excel sheet layout) tailored to your location and vehicle — tell me your ZIP/postal code and EV model.