Load Calculation for Solar System
Load Calculation for Solar System: Description
Load calculation is the first and most critical step in designing an efficient solar power system. It determines the total energy consumption of your appliances, helping you choose the right solar system size, battery capacity, and inverter rating.
How to Calculate Your Load
1. List All Appliances
Note each device’s:
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Wattage (e.g., LED bulb: 10W, AC: 1500W)
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Usage Hours/Day (e.g., fridge: 24h, fan: 8h)
2. Calculate Daily Energy (Watt-Hours)
Formula:
Wattage × Hours Used = Daily Watt-Hours (Wh)
Example:
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Fridge: 200W × 24h = 4,800Wh
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3 Fans: 75W × 8h × 3 = 1,800Wh
3. Add Backup Time (For Off-Grid)
Battery Size Formula:
Total Daily Wh ÷ Battery Voltage (12V/24V/48V) = Ah Required
Example:
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10,000Wh ÷ 48V = 208Ah (Add 30% buffer = 270Ah)
4. Solar Panel Sizing
Formula:
Daily Wh ÷ (Peak Sun Hours × 0.8 efficiency) = Panel Wattage
Example (5 sun hours):
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10,000Wh ÷ (5 × 0.8) = 2,500W (e.g., 10 × 250W panels)
Key Considerations
Startup Surge: ACs/fridges need 2-3x rated power briefly
Inverter Rating: Must exceed total running wattage
Weather Buffer: Add 20-30% extra panel capacity