## Calculate Size of Solar Panel

Calculate Size of Solar Panel, No of Solar Panel and Size of Inverter for following Electrical Load

• 1 No’s of 100W Computer use for 8 Hours/Day
• 2 No’s of 60W Fan use for 8 Hours/Day
• 1 No’s of 100W CFL Light use for 8 Hours/Day

Solar System Detail:

• Solar System Voltage (As per Battery Bank) = 48V DC
• Loose Wiring Connection Factor = 20%
• Daily Sunshine Hour in Summer = 6 Hours/Day
• Daily Sunshine Hour in Winter = 4.5 Hours/Day
• Daily Sunshine Hour in Monsoon = 4 Hours/Day

Inverter Detail:

• Future Load Expansion Factor = 10%
• Inverter Efficiency = 80%
• Inverter Power Factor =0.8

### Calculation:

Step-1: Calculate Electrical Usages per Day

• Power Consumption for Computer = No x Watt x Use Hours/Day
• Power Consumption for Computer = 1x100x8 =800 Watt Hr/Day
• Power Consumption for Fan = No x Watt x Use Hours/Day
• Power Consumption for Fan = 2x60x8 = 960 Watt Hr/Day
• Power Consumption for CFL Light = No x Watt x Use Hours/Day
• Power Consumption for CFL Light = 1x100x8 = 800 Watt Hr/Day
• Total Electrical Load = 800+960+800 =2560 Watt Hr/Day

Step-2: Calculate Solar Panel Size

• Average Sunshine Hours = Daily Sunshine Hour in Summer+ Winter+ Monsoon /3
• Average Sunshine Hours = 6+4.5+4 / 3 =8 Hours
• Total Electrical Load =2560 Watt Hr/Day
• Required Size of Solar Panel = (Electrical Load / Avg. Sunshine) X Correction Factor
• Required Size of Solar Panel =(2560 / 4.8) x 1.2 = 635.6 Watt
• Required Size of Solar Panel = 635.6 Watt

Step-3: Calculate No of Solar Panel / Array of Solar Panel

If we Use 250 Watt, 24V Solar Panel in Series-Parallel Type Connection

• In Series-Parallel Connection Both Capacity (watt) and Volt are increases
• No of String of Solar Panel (Watt) = Size of Solar Panel / Capacity of Each Panel
• No of String of Solar Panel ( Watt) = 635.6 / 250 = 2.5 No’s Say 3 No’s
• No of Solar Panel in Each String= Solar System Volt / Each Solar Panel Volt
• No of Solar Panel in Each String= 48/24 =2 No’s
• Total No of Solar Panel = No of String of Solar Panel x No of Solar Panel in Each String
• Total No of Solar Panel = 3×2 =6 No’s
• Total No of Solar Panel =6 No’s

Step-4: Calculate Electrical Load:

• Load for Computer = No x Watt
• Load for Computer = 1×100 =100 Watt
• Load for Fan = No x Watt
• Load for Fan = 2×60 = 120 Watt
• Load for CFL Light = No x Watt
• Load for CFL Light = 1×100 = 100 Watt
• Total Electrical Load = 100+120+100 =320 Watt

Step-5: Calculate Size of Inverter:

• Total Electrical Load in Watt = 320 Watt
• Total Electrical Load in VA= Watt /P.F
• Total Electrical Load in VA =320/0.8 = 400VA
• Size of Inverter =Total Load x Correction Factor / Efficiency
• Size of Inverter = 320 x 1.2 / 80% =440 Watt
• Size of Inverter =400 x 1.2 / 80% =600 VA
• Size of Inverter = 440 Watt or 600 VA

### Summary:

• Required Size of Solar Panel = 635.6 Watt
• Size of Each Solar Panel = 250 Watt. 12 V
• No of String of Solar Panel = 3 No’s
• No of Solar Panel in Each String = 2 No’s
• Total No of Solar Panel =6 No’s
• Total Size of Solar Panel = 750 Watt
• Size of Inverter = 440 watt or 600 VA

## Calculate Cable Trunking Size

Example: Calculate PVC Trunking size for following Power Cables running through Trunking .Consider 10% as Future expansion

• 30 No’s of 1.5 Sq.mm Stranded Cables
• 50 No’s of 2.5 Sq.mm Stranded Cables
• 20 No’s of 4 Sq.mm Stranded Cables
 Cable Factor for Trunking as per IEEE Type of Cable Size of Cable Factor Solid 1.5 7.1 Solid 2.5 10.2 Stranded 1.5 8.1 Stranded 2.5 11.4 Stranded 4 15.2 Stranded 6 22.9 Stranded 10 36.3 Stranded 16 50.3 Stranded 25 75.4 Stranded 35 95 Stranded 50 132.7 Stranded 70 176.7 Stranded 95 227 Stranded 120 284 Stranded 150 346
 Trunking Factor As per IEEE Trunking Size (mm) Factor 75 X 25 738 50 X 37.5 767 100 X 50 993 50 x 50 1037 75 X 37.5 1146 100 X 37.5 1542 75 X 50 1555 100 X 50 2091 75 X 75 2371 150 X 50 3161 100 X 75 3189 100 X 100 4252 150 X 75 4787 150 X 100 6414 150 X 150 9575

## Calculations:

• As per Table Cable Factor for 1.5 Sq.mm Stranded Cable=8.1
• As per Table Cable Factor for 2.5 Sq.mm Stranded Cable=11.4
• As per Table Cable Factor for 2.5 Sq.mm Stranded Cable=22.9
• Total Cable Factor= No of Cables X Cable Factor
• Total Cable Factor=(30X8.1)+(50X11.4)+(20X22.9)
• Total Cable Factor=1271
• Total Cable Factor After 10% Future Expansion=1271+127 =1398
• As per Table Suitable Size for PVC Trunking for Cable Factor 1398 is 100 X 37.5