A PV system using battery charger can provide the necessary power when there is no sun. The manufacturer has provided following parameters (All measurements are done at standard condition of AM1.5 G spectrum) of an Indi dual solar cell.
Open circuit voltage =0.6 volt
Short circuit current density = 40 x 10-3 A/cm2
Fill factor = 0.80
Area of the cell = 120 cm2
Assume that you would like to use this type of solar cell to build a 12 volt battery charger where the solar cell intensity is 6 kWH/m2 per day and the yearly average temperature is 250C. The battery charger must provide at least 1 kWH per day. Further assume that all solar cells are going to provide identical power and there is no loss power in connecting the solar cells. How many solar cells should be connected in a string? How many strings we will require to get the desired energy of 1 kWH per day?