5kW Off-Grid Solar PV System Design - Hybrid

Project Requirements:

• Total load = 5kW
• Battery backup time = 1 hour
• Primary source = Solar PV
• Secondary source = Grid
• Tertiary source = Battery Bank

System Design:

1. Solar Panels:

Wattage of single panel = 235Wp

No. of solar panels = (Total load x 1.4) / 235

                                = (5000 x 1.4) / 235
                                = 30 (rounded value)
     2.  Inverters:
Company = SMA
Two types of inverters (built in charge controllers) will be used.
a). Sunny Boy     b). Sunny Island

a) Sunny Boy:
Requirement for sunny boy = 7000W*
* 5000W x 1.4 = 7000Wp
Suitable sunny boy (according to the requirement) = SMC 7000 TL

SMC 7000 TL

b). Sunny Island
Requirement for sunny island = 5000W*
* Sunny island runs the load, so its rating depends upon total load.
Suitable sunny island (according to the requirement) = SI 5048

SI 5048

     3. Solar PV array design:
According to the data sheet of SMC 7000 TL, the input DC voltage capacity of SMC 7000 TL is 750V. It has four inputs of solar PV arrays. The input voltage of one array must not be greater than 90 % of 750V. 
Since the open circuit voltage of one solar PV panel is around 34V. Connecting 15 solar panels in series will give us (15*34) 510V DC which is smaller than 675V (90% of 750V).
So we can make two solar PV arrays, having 15 panels each. All the 15 solar panels will be connected in series in one array.

     4. Battery Bank:
Battery rating is defined in terms of Ampere Hours (Ah). We can find out the Ah for battery bank according to the load and backup time.
Ah = (Load x backup time) / (DOD x PF x System Voltage)
Now
   load = 5000
   backup time = 1 hour
   DOD (depth of discharge) = 0.6
   PF (power factor) = 0.8
   System voltage = 48V
So
Ah = (5000 x 1) / (0.6 x 0.8 x 48)
      =  217.01
So now we need 217Ah @ 48V for battery bank.
Rating of single battery = 200Ah @ 12 V
Connecting four batteries of above rating, in series, will give us 200Ah @ 48V.

System Topology:

Circuit Diagram:

You may also know:
a) HOW TO DESIGN AN OFF-GRID (HYBRID) SOLAR PV SYSTEM USING SMA SOLAR INVERTERS
b) CIRCUIT DIAGRAM FOR 5KW OFF-GRID SOLAR PV SYSTEM

Posted in: Hybrid, Off-Grid, Solar PV, Solar PV Projects