Concept and experiments, of solar panel This is a solar panel, solar panel, consists of many small solar cells, this is one solar cell, this is also called photo voltaic cell, the function of solar cell is, to convert light energy, into electrical energy, when, sufficient light falls on the cell, then 0.5 volt is generated, at output at full load, this means, one solar cell, will generate 0.5 V at full load. if more voltage is required, then, many cells to be connected in series, so here, 1, 2, 3, 4, 5, 6, 7, 8, 9, so 9 solar cells are here, and 9 cells are here, this is also one solar cell, so total 18 cells are here in series, each cell produce 0.5 volts, so 18 cells, in series will produce 9 V, this middle line can be seen here, is actually a bus bar, purpose of this bus bar is, to collect current, from the surface of the cell, Now I will show, back side of the panel, this is back side of the panel, these are terminals, plus and minus, 2 wires are connected here, and tape to stop wire movement, this is name (rating) plate, Specifications, of the panel are written here, I will show it from close, this is rating plate, specification are given here, this column, is number of cells in panel cells may be 1 or 12 or 18, or some other number in 1 panel, voltage at full load, voltage at no load, for 1 cell panel, output voltage will vary, from 0.5 V to 0.6 V, output is 0.5 V at full load, and output will be 0.6 V at no load, these are approximate values, and depends on load, if we connect 12 cells in series, then output voltage, will be 12 X 0.5 , so we get 6 V at full load, and output will be 7.2 V at no load, if 18 cells are connected in series, then output voltage at full load, will be 18 X 0.5 = 9 Volts, and voltage at no load will be 10.8 V, The panel shown in this video, has 18 cells, connected in series, full load output voltage is 9 V, full load current is 0.57 Amps, And no load voltage will be 10.8 V, 9 volt out at full load, can charge 6 V battery, this is, I-V curve of solar cell or panel, this is voltage axis, this is current (in Y axis), this is current plot (curve), this point, corresponds to power at max.
Load, Pmax, voltage at this point is called, voltage at maximum power, current at point is called, current at maximum power Imp, voltage at Pmax point, is this much, this is voltage is Vmp, How much is Imp?, this much current is Imp, at this point, current is zero, here also I is zero, it is called, open circuit voltage Voc, this point, corresponds to short circuit, means, voltage is zero, current at this point is called, I short circuit, at this point, voltage is this much, and current is this much, at this point, voltage is this much, and current is much, so V & I are different at, different points, this is max.
Power point, Now, I will explain power curve, This green line is power curve, Max. power is at this point, Power is zero at these 2 point, Power is equal to V X I, as current is zero here, so power will be zero, here I & V both are zero, so power is zero, Max. power is at this point, this is solar panel, this is simple circuit, to measure open circuit voltage, this multi meter is, connected at output of solar panel, Multimeter is set at 20 V DC, Load is not connected to output, if load is not connected then, it is called open circuit condition, Now let us go to roof for sunlight, to check the Voc of the panel, Here solar panel, is kept under sunlight, this is plus terminal, this is minus, plus of panel is connected, to plus of the multimeter minus is connected to COM, Multimeter is set at 20 V DC, no load at output, Open circuit voltage, is coming 10.17 V, this circuit arrangement is, to measure short circuit current, Here one multimeter is, connected to the output of solar panel, multimeter is set at 10 A DC, At the amp scale of the meter, both terminals of the multimeter, are short inside the multimeter, so solar panel output, is short like this, so short ckt.
Current is flowing, and this multimeter, will show short circuit current, now we will do practical for Isc, output of the panel is short here, multimeter scale is set at 10 A DC, Out of panel is short circuit, when setting is amp, inputs will be shorted inside, Isc current is 0.6 A, sun light is less now, If sun light increases, then more current will flow, this is simple circuit, to check voltage of solar panel, at maximum load / power, Out put is connected, to a resistor, value of this resistor, is such that, current flowing in output will be, equal to current rating, at maximum power, now we can check, voltage across resistor, setting of multimeter is 20 V DC, Now we will do practical for this, one load is connected at output, this is +, this is minus, value of load resistor is 16.5 ohms, 16.5 ohm correspond to max.
power, Voltage at output is 8.08 V, sun light is less now, if sun light increases, then we get, more voltage at output, advantage of solar cell / panel, no pollution, long life, no maintenance cost, sun light is free, so raw material is free, disadvantages, high cost of installation, low efficiency, during cloud & night, energy can not be generated, then we will have, to depend on the battery,.