Power Calculation Result
What is the EV Charger Power Calculator?
The EV Charger Power Calculator is an electrical calculation tool designed for EV charger installation engineers, electrical designers, and vehicle owners. Based on the fundamental AC circuit formulas P = √3 × U × I × cosΦ (three-phase) or P = U × I × cosΦ (single-phase), it provides real-time calculations of active power, reactive power, and apparent power for EV chargers.
Enter the voltage (single-phase 220V or three-phase 380V), current, and power factor to obtain the actual charging power of the EV charger, distribution capacity requirements, and recommended vehicle compatibility.
Key Features
- Single-phase / Three-phase auto-switch: Supports 220V single-phase residential and 380V three-phase industrial meters
- Triple power output: Displays active kW, reactive kVar, and apparent kVA simultaneously, facilitating distribution design
- EV charger sizing recommendations: 8 tiers — 7kW / 11kW / 22kW / 43kW / 60–100kW / 120–160kW / 240kW / 400kW+, matching various vehicle classes and distribution capacities
- Integrated cable specs: Each tier recommendation includes the recommended leakage protection switch and cable cross-section directly — no need to check the FAQ
- Typical scenario presets: One-click loading for common EV charger tiers:
- AC tier: Home 7kW (220V/32A), Three-phase 11kW (380V/16A), Three-phase 22kW (380V/32A), Three-phase 43kW (380V/63A, actual ≈40.5kW)
- DC cabinet tier: 30kW / 60kW / 80kW / 100kW / 120kW / 160kW / 240kW / 400kW / 480kW (equivalent current values at the 380V three-phase input side)
- High-power alerts: Prompts for 690V/10kV medium-voltage distribution when current ≥400A, preventing 380V overload
- Pure frontend: No backend, no data upload — safe for sensitive distribution scenarios
Frequently Asked Questions (FAQ)
What is the EV charger power calculation formula?
Three-phase formula: P = √3 × U × I × cosΦ (U = line voltage, I = line current). Single-phase formula: P = U × I × cosΦ. The power factor cosΦ is typically 0.95–1.0. EV battery charging is nearly purely resistive, so 0.98 is the common assumption.
How many amps does a 7kW EV charger need?
Single-phase 220V × 32A ≈ 7kW — a 7kW home charger requires a 32A leakage protection switch and 6mm² copper cable. For an 11kW three-phase charger, a three-phase 380V × 16A configuration is needed with 5×4mm² five-core cable.
What is the difference between 22kW and 11kW EV chargers?
11kW is three-phase 380V × 16A and 22kW is three-phase 380V × 32A. Both require a three-phase meter, but 22kW doubles the charging speed. Note: Tesla Model 3/Y standard onboard charger limits to 11kW — even plugging into a 22kW charger will only yield 11kW.
How do I size an EV charger — 7kW / 11kW / 22kW? The tool’s recommendation panel gives the corresponding leakage protection + cable specs directly.
- 7kW single-phase 220V: Suitable for most home scenarios, no three-phase meter application needed — the mainstream choice
- 11kW three-phase 380V: 57% faster charging, ideal for frequent commuters (2–3 charges per week)
- 22kW three-phase 380V: Suitable for commercial locations or two-vehicle households — confirm vehicle compatibility (some models are limited to 11kW)
- 43kW three-phase 380V/63A: Industrial scenarios or large buses — actual active input ≈40.5kW (cosΦ=0.98)
- 30–480kW DC cabinets: Commercial fast charging, buses/logistics, ultra-fast charging stations — see the preset buttons above for detailed sizing
- Sizing formula: Weekly charging demand kWh = battery capacity × 0.6 (日常 SOC range) ÷ charging power ≤ 7 (once per week) or ≤ 11 (2–3 times per week)
How do I size distribution switches and cables?
- 7kW: 32A leakage protection + 6mm² copper core + 1.5P circuit breaker
- 11kW: Three-phase 16A leakage protection + 5×4mm² five-core cable + 3P circuit breaker
- 22kW: Three-phase 32A leakage protection + 5×6mm² five-core cable + 3P circuit breaker
- 43kW: Three-phase 63A leakage protection + 5×10mm² five-core cable + 3P 80A circuit breaker
- 60–120kW DC cabinet: Three-phase 100A leakage protection + 5×16mm² cable; cabinet has built-in DC/DC rectification module
- 160–240kW dual-gun: Three-phase 250A main leakage protection + busbar supply
- 400–480kW ultra-fast charging: Typically 690V/10kV medium-voltage entry, liquid-cooled terminals — requires dedicated power system design
- For runs exceeding 50m, upsizing cables one tier (e.g., use 10mm² for 7kW) to prevent excessive voltage drop
What is the power factor cosΦ?
The power factor is the ratio of active power to apparent power, cosΦ = P / S. EV battery charging is nearly purely resistive, with power factors reaching 0.95–1.0. For EV charger power calculations, 0.98 is the typical assumption.