EV Charger Solar Sizing Calculator

Size a solar system that matches your charger. Model seasonal sun hours and real-world efficiency. Plan costs, rebates, and returns before you install today.

Calculator inputs
Responsive layout: 3 columns large, 2 columns smaller, 1 column mobile
Miles driven on the days you typically charge.
Typical range: 0.22–0.38 for many EVs.
Used to convert your driving-day energy to annual.
Covers heat, conversion, and cable losses.
Used for inverter guidance when adding storage.
100% aims to cover EV energy annually.
Site average; check local solar maps.
Accounts for temperature, wiring, and inverter losses.
Used to convert system size into panel count.
Use your blended rate including delivery charges.
System cost before rebates and incentives.
Applied to installed cost.
Add any extra cash rebate or credit estimate.
Covers cleaning, monitoring, and minor repairs.
Reduces solar output slightly each year.
Annual change in electricity rate.
Used to compute NPV over the analysis period.
Commonly 20–25 years for solar assets.
Use this if you want to charge mostly at night or during outages.
Percent of EV energy shifted to nighttime.
How many days of night energy to store.
Usable fraction of nameplate capacity.
Energy you get back after storage losses.
All-in installed storage cost estimate.
Used when battery sizing is enabled.
Reset
Tip: After calculating, use the download buttons in the results card.
Example data table
Sample scenarios to sanity-check inputs
Scenario Daily miles Efficiency Sun hours Derate Offset Panels (400 W) Estimated kW
City commute 20 0.26 kWh/mi 4.5 80% 100% 7 2.8
Suburban 30 0.30 kWh/mi 5.0 80% 100% 10 4.0
High mileage 60 0.34 kWh/mi 5.5 78% 110% 22 8.8
Examples are illustrative; local conditions can shift results.
Formula used
  1. Driving-day EV energy = daily miles × kWh per mile × (1 + charging losses).
  2. Annual EV energy = driving-day EV energy × driving days per week × (365 ÷ 7).
  3. Target solar energy = annual EV energy × solar offset target.
  4. Annual kWh per kW = peak sun hours × 365 × system derate.
  5. Solar size (kW) = target solar energy ÷ annual kWh per kW.
  6. Panel count = ceil(solar size × 1000 ÷ panel wattage).
  7. Year‑1 value = expected annual kWh × electricity rate.
  8. Simple payback = net cost ÷ (year‑1 value − annual O&M).
  9. NPV discounts annual cash flows using the discount rate, applying degradation and escalation each year.
  10. Battery nameplate = usable night energy ÷ (DoD × efficiency).
How to use this calculator
  • Enter your daily miles and kWh per mile from your vehicle’s dashboard or app.
  • Set driving days per week so annual energy reflects your real routine.
  • Pick local peak sun hours and a realistic system derate for losses.
  • Adjust offset target if you want partial or extra coverage.
  • Add rate, system cost, and rebates to estimate payback and returns.
  • Enable battery sizing if nighttime charging or resilience matters.
  • Press Calculate. Results appear above the form under the header.
  • Use Download CSV or Download PDF to save your summary.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.