Solar

Solar system (PV) calculation and design:

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Solar panel (PV) is a device which can convert energy from light energy (proton) to electrical
energy. Each panel is rated by its DC output power. Currently the best commercial solar panel
(PV) efficiency is around 17.4%. Solar panels are normally 12V DC output. In large solar panel
24V or 48V DC output also seen.

A technical specification (backside of a solar panel) given below.

Normally a few common specification
are seen all types of solar panel
Like Nominal voltage, Maximum
Voltage, Open circuit Voltage,
Maximum Current, Short Circuit
Current, Maximum System Voltage, and
Maximum Power.

Maximum Power: it means it can deliver maximum 20 Watts electricity. If we need total 100
Watts then we need to setup 5 panel in parallel or series (depend on design).

Maximum Voltage: it means its maximum output voltage is 17.6V

Open Circuit Voltage: It means the voltage without load. It is sometimes given the symbol Voc

Maximum Current: It means the maximum output current.

Short Circuit Current: It means the current of short circuit of solar panel.

Maximum System Voltage: It means that, when we connect solar panel in series then
maximum voltage limit is 600V so we could connect (600/17)=35 solar panel in series.

Now if a subscriber wants to setup a solar system for 2 bulbs and 1 fan. (12 volt DC)
(1 bulb=10 watt, 1 fan=20 watt) then the total load
2 bulb (10×2) = 20 watt
1 fan = 20 watt
Total = 40 watt

Now if he wants 4 hours back up time.
Then total load (4hour × 40watt) = 160 (watt per hour)
To measure the battery ampere for the above load.
Volt = 12
I =
Battery is needed 12 volt, 14 AH.

Now to calculate the solar panel:
To calculate the solar system we have to
measure
1. Solar Panel
2. Charge controller
3. Battery
4. Inverter (for AC output)

Generally a battery charging current = 10% of its AH
Charging current = 1.4 A ( )
Solar panel needed = 1.4 A 12 V
= 16.8 watt

So recommended the charge controller is 12 Volt, 1.4 Amp
Thus a solar system is calculated
(System loss is not added with this measurement, so approximate 25% system loss will be
added.)
So from calculation
1. Solar panel =20 watt (20 watt is available)
2. Battery = 12volt, 15AH (15AH, 20AH battery available)
3. Charge controller = 12 volt, 2A (2A charge controller available)

Efficiency of Solar panel:
Here output power is the power we get from solar panel. Input power is the light fall in solar
panel.

The light comes from sun in earth surface is 1M2=1KW.
It means from 1M2 space we could get maximum 1KW energy. If a 1M2 (dimension) solar panel
deliver 170 Watts power then the efficiency of solar panel is17%.