This tool helps you design a solar power system by calculating the required solar panel capacity, battery bank size, inverter rating, and charge controller size. Enter your daily energy consumption, peak sun hours, and system parameters to get a complete system design.
📐 Solar System Sizing Formulas
Solar Panel kW: kW = (kWh × 1.2) / Sun Hours Battery Bank Ah: Ah = (kWh × 1000 × Days) / (V × DOD) Inverter VA: VA = (kW × 1000) / 0.85 Charge Controller (A): CC = (kW × 1000) / V
Where: kWh = Daily Energy Consumption Sun Hours = Peak Sun Hours V = System Voltage DOD = Depth of Discharge (%) Days = Battery Backup Days
📊 Solar System Sizing Reference
Daily Load (kWh)
Solar Panel (kW)
Battery (Ah @48V)
Inverter (kVA)
2
0.5
100
2.5
3
0.8
150
3.5
5
1.2
250
6.0
8
2.0
400
9.5
10
2.5
500
12.0
15
3.8
750
18.0
20
5.0
1000
24.0
📌 Solar System Components
Solar Panels: Convert sunlight to DC electricity. Rated in Watts (Wp).
Charge Controller: Regulates battery charging. MPPT is more efficient than PWM.
Battery Bank: Stores energy for use during non-sunny hours.
Inverter: Converts DC to AC for household appliances.
Mounting Structure: Supports panels at optimal angle.
💡 Peak Sun Hours by Region (India)
Region
Peak Sun Hours
Annual kWh/kWp
Rajasthan / Gujarat
5.5-6.5
2000-2400
Maharashtra / MP
5.0-5.5
1800-2000
North India (UP, Punjab)
4.5-5.0
1600-1800
East India (WB, Odisha)
4.0-4.5
1400-1600
South India (TN, Karnataka)
5.0-5.5
1800-2000
North East
3.5-4.0
1200-1400
🔧 How to Use This Calculator
Enter daily energy consumption (kWh) - from your electricity bill or load calculation
Enter peak sun hours - based on your location (see table above)
Select system voltage - 12V, 24V, or 48V
Enter battery backup days - how many days of autonomy needed
Select DOD - based on battery type
Select system losses - typical 15%
Results include solar panel kW, battery Ah, inverter VA, and charge controller size
❓ Frequently Asked Questions (FAQ)
❓ How to size a solar system? ▼
Solar kW = (kWh × 1.2) / Sun Hours. Battery Ah = (kWh × 1000 × Days) / (V × DOD). This calculator does both.
❓ How many solar panels do I need for 5kWh? ▼
For 5kWh daily with 5 sun hours, you need 1.2 kW of solar panels. With 400W panels, that's 3 panels.
❓ What is the difference between 12V, 24V, and 48V systems? ▼
48V is most efficient for larger systems (reduced current, lower losses). 12V is for small systems (RV, boat). 24V is for medium systems.
❓ What is MPPT vs PWM charge controller? ▼
MPPT (Maximum Power Point Tracking) is 20-30% more efficient than PWM. Recommended for all but the smallest systems.
❓ How much battery do I need for a solar system? ▼
Battery Ah = (kWh × 1000 × backup days) / (V × DOD). For 5kWh with 2 days backup at 48V and 90% DOD, you need 231 Ah.
❓ What size inverter do I need? ▼
Inverter size should be 1.2-1.5× the maximum load. For a 5kW system, use a 6-7.5kVA inverter.