Battery & energy
EV Home Charging Planner
Estimate the overnight energy and charging time for one or two EVs. Compare a shared charging limit and reduced average power without treating the result as approval for your panel or wiring. The linked Tesla source explains power-management options; available power here is your scenario, not a measurement of spare electrical capacity.
Plan EV home charging from daily distance, vehicle efficiency, overnight hours, charger power, charging losses, battery state of charge, and electricity rate.
Calculated result
EV home charging plan
Calculating…
Calculated locally in your browser
Planning math only. Verify equipment specifications and installation requirements separately.
What this calculator returns
The result checks whether the entered power can replace a driving day within your charging window. In two-EV mode it adds both vehicles' energy and uses one shared power budget. Both vehicles are assumed to be available during the same window, and energy can be allocated without vehicle-specific bottlenecks. Monthly costs use each vehicle's driving days. Range restored per hour and the optional SOC check refer to the first EV alone.
Can two EVs share home charging?
Compare energy needs before comparing charger nameplate ratings. A household may need less average overnight power than the combined ratings suggest, but the installation still needs a professional assessment.
- One shared energy budget
- Enter the real total charging limit, both vehicles' daily driving, and a window when both are available. The model assumes sequential or shared charging can use that budget.
- Test reduced availability
- Try a lower average-power percentage if household loads limit charging. Dynamic load management responds to measured site demand; group power sharing divides a limit between chargers. This tool simulates neither controller.
- Verify the installation
- A sufficient energy result does not prove spare panel capacity or eliminate a service upgrade. Ask a qualified installer to assess listed equipment, compatibility and local requirements.
Formula and variables
The calculation runs entirely in your browser. Static formulas, definitions, examples, and tables remain readable without JavaScript.
Daily battery kWh = distance ÷ efficiency for distance-per-kWh units, or distance × energy-per-distance for consumption units. Household kWh adds both EVs when selected. Minimum average wall power = household kWh ÷ (overnight hours × charging efficiency). Charging time = household kWh ÷ (shared power limit × available-power fraction × charging efficiency).
- d
- User-entered daily driving distance in miles or kilometers.
- e
- Vehicle energy efficiency in the selected distance or consumption unit.
- Eday
- Battery energy needed to replace the modeled daily driving.
- ηcharge
- User-entered wall-to-battery charging efficiency.
- Pwall
- Charger wall power or minimum average wall power for the entered overnight window.
Range restored per hour uses the first EV's efficiency. Monthly grid energy adds each vehicle's daily energy times its driving days, multiplies by 52 ÷ 12, and divides by charging efficiency. The available-power percentage changes time, not the energy needed. The optional SOC check assumes the first EV can use the whole modeled power budget.
Worked example
| Input | Value |
|---|---|
| Distance unit | Miles |
| Typical daily driving | 40 mi / km |
| Vehicle efficiency unit | mi/kWh |
| Vehicle efficiency | 3.5 |
Driving 40 miles/day at 3.5 mi/kWh uses about 11.43 kWh of battery energy. With 10 hours and 90% charging efficiency, about 1.27 kW average wall power replaces it overnight.
Reference table
| Wall power | Battery energy/hour | Range/hour at 3.5 mi/kWh | Typical scenario label |
|---|---|---|---|
| 1.44 kW | 1.30 kWh | 4.5 miles | Level 1 |
| 3.84 kW | 3.46 kWh | 12.1 miles | Lower-power Level 2 |
| 7.68 kW | 6.91 kWh | 24.2 miles | Higher-power Level 2 |
| 11.52 kW | 10.37 kWh | 36.3 miles | High-power Level 2 |
Frequently asked questions
Is Level 1 enough for my daily driving?
Compare the 1.44 kW scenario with your entered overnight window. If its calculated time is within that window, it replaces the modeled daily energy under your assumptions.
How is this different from the EV Charging Cost Calculator?
This planner starts with daily driving to find needed home charging power. The cost calculator starts with a battery SOC change for one charging session.
Does this tell me what breaker or wiring I need?
No. It intentionally reports only energy and charging power; an appropriate professional must verify installation requirements.
Assumptions and limitations
- No breaker, conductor, branch-circuit, electrical-panel, service-capacity, connector, or code-compliance calculation.
- Vehicle limits, charger limits, taper, battery conditioning, temperature, scheduled charging, and auxiliary loads can change actual power and time.
- Efficiency and driving pattern are user assumptions; use vehicle trip data when available.
- Installation requirements must be verified by an appropriate professional.
Method and sources
Review the electrical formulas, calculation methodology, and standards status for the references most relevant to this calculation. The broader technical sources index records source scope and provenance. Content release .