Solar Panel Inverter Size Calculator
Calculate the optimal inverter size for your solar panel system
Solar Inverter Size Calculator
Based on IEEE 1547 and NEC Standards
Results:
Total Solar Array: 0 W
Recommended Inverter Size: 0 W
Minimum Inverter Size: 0 W
Maximum Inverter Size: 0 W
System Efficiency: 0%
Daily Energy Production: 0 kWh
How to Use Solar Panel Inverter Size Calculator
Grid-Tie Systems
- Select "Grid-Tie System" type
- Enter individual solar panel wattage
- Input total number of panels
- Choose system voltage (typically 240V or 480V)
- Enter peak sun hours for your location
- Adjust inverter efficiency (95-98% typical)
- Set derating factor (80-90% recommended)
Off-Grid Systems
- Select "Off-Grid System" type
- Enter solar panel specifications
- Input daily energy consumption in kWh
- Choose appropriate system voltage
- Consider battery bank requirements
- Account for system losses and inefficiencies
- Size inverter for peak load demands
Hybrid Systems
- Select "Hybrid System" type
- Balance grid-tie and battery backup needs
- Consider both daily load and backup requirements
- Account for battery charging efficiency
- Size for maximum simultaneous loads
- Include safety margins for system reliability
How to Calculate Solar Panel Inverter Size
Step 1: Calculate Total Array Size
Formula: Total Array = Panel Wattage × Number of Panels
Example: 400W × 20 panels = 8,000W (8kW)
Step 2: Apply Derating Factors
Formula: Derated Array = Total Array × Derating Factor
Example: 8,000W × 0.85 = 6,800W
- Temperature losses: 10-15%
- Shading losses: 5-10%
- Wiring losses: 2-3%
- Dust/soiling: 2-5%
Step 3: Size Inverter
Grid-Tie: 75-125% of array size
Off-Grid: Based on peak load + 20% safety margin
Example: 6,800W × 1.0 = 6,800W inverter
Real-Life Calculation Example
Scenario: Residential grid-tie solar system
Given:
• Solar panels: 400W each
• Number of panels: 25
• System voltage: 240V
• Peak sun hours: 5.5
• Inverter efficiency: 96%
• Derating factor: 85%
Calculations:
Step 1: Total Array = 400W × 25 = 10,000W (10kW)
Step 2: Derated Array = 10,000W × 0.85 = 8,500W
Step 3: Recommended Inverter = 8,500W (8.5kW)
Step 4: Daily Production = 8.5kW × 5.5h × 0.96 = 44.9 kWh
Result:
Recommended Inverter Size: 8,500W (8.5kW)
Range: 7,500W - 10,000W (depending on specific requirements)
Inverter Sizing Formulas
Total Solar Array:
Array Size = Panel Wattage × Number of Panels
Derated Array Power:
Derated Power = Array Size × Derating Factor
Grid-Tie Inverter Size:
Inverter Size = Derated Power × (0.75 to 1.25)
Off-Grid Inverter Size:
Inverter Size = Peak Load × 1.2
Daily Energy Production:
Daily kWh = Inverter Size × Peak Sun Hours × Efficiency
Sizing Guidelines
Grid-Tie Systems
- Inverter: 75-125% of array
- Optimal: 90-110% of array
- Consider local regulations
Off-Grid Systems
- Size for peak load + 20%
- Consider surge requirements
- Account for battery charging
Safety Factors
- Temperature derating: 10-15%
- System losses: 15-20%
- Future expansion: 10-20%