The main difference from the solar cell is essential for the production of solar cell. Materials solar cell that the most common cells are crystalline silicon. Crystalline materials can consist of a single crystal, mono or single-crystalline, and poly or multi-crystalline. In addition there are solar cells made from panels of thin layers of amorphous silicon. Tues Crystalline silicon has two types are almost similar, although the single crystalline cells more efficiently than poly-crystalline poly-crystalline as a bond between the cells. The advantages of amorphous silicon is affordable but not as efficient crystalline silicon solar cell.
Know Your Cell Solar Panel Performance

Total spending power (wattage) of solar cell is proportional to the voltage / operating voltage multiplied by the flow of current operations. Solar cell can generate currents of different voltages. This differs from the battery, which flows from a relatively constant voltage.

Output characteristics of solar cell can be seen from the performance curve, called the IV curve. Curse IV shows the relationship between current and voltage.

Solar Cell Panel IV-Curve
Picture above shows the typical I-V curve. Voltage (V) is the horizontal axis. Current (I) is the vertical axis. Most of the IV curve is given in the Standard Test Conditions (STC) 1000 watts per square meter of radiation (or called a sun peak / peak sun one hour) and 25 degrees Celsius / 77 degrees Fahrenheit temperature of solar cell panels. For information on the STC represents optimal conditions in a laboratory environment.

I-v curve consists of three important things:

1. Maximum Power Point (Vmp and Imp)
2. Open Circuit Voltage (VOC)
3. Short Circuit Current (ISC)
Maximum Power Point (Vmp & Imp)

In the IV curve, Maximum Power Point Vmp and Imp, is the operating point, with a maximum expenditure / output generated by solar cell panels during operational conditions. In other words, Vmp and Imp can be measured at the moment given the burden of the solar cell panels at 25 degrees Celsius and radiation of 1000 watts per square meter. In the curve above 17 volts is the voltage Vmp and Imp is 2.5 amperes. Number of watts at the maximum limit is determined by multiplying the Vmp and Imp, the maximum number of watts at STC is 43 watts.

Output decreases as the voltage decreases. Flow and power output of most solar cell module panel decreases as voltage / voltage rise exceeds the maximum power point.

Open Circuit Voltage (VOC)

Open Circuit Voltage, VOC, is the capacity of the maximum voltage that can be achieved when the absence of flow (current). At the I-V curve, VOC is 21 volts. Power at the time of VOC is 0 watts.
Voc solar cell panel can be measured in the field in various circumstances. When buying a module, it is highly recommended to test the voltage to determine whether they fit with the factory specification. When testing the voltage with a digital multimeter from the positive terminal to negative terminal. Open Circuit Voltage (VOC) can be measured in the morning and afternoon.
Short Circuit Current (ISC)

Short Circuit Current ISC, is at maximum output current from the solar cell panels that can be removed (output) under conditions with no resistance or short circuit. In the IV curve above shows the current estimate of 2.65 Amperes. Power on the ISC is 0 watts.

Short circuit current can be measured only when creating a direct connection of positive and negative terminals of the solar cell module panel.
Label Specifications Solar Cell Panel

All values found in the IV curves are used to create specific labels for each module solar cell panels. All models ditera under standard test conditions. Label Specifications can be found at the rear of the solar cell module panel:
Electrical ratings at 1000 Watt/m2
AM 1.5, Cell 25 degree Celsius Temperature
Max. Power: 43 W
VOC: 4.21 V
Vmp: 17.3 V
ISC: 2.65 A
Imp: 2.5 A
Factors Affecting Solar Cells Panel
Five major things that affect the performance / performance of the module solar cells:

1. Materials manufacturer solar cells panel
2. Load resistance
3. Sunlight intensity
4. Temperature / temperature of solar cells panel
5. Shadow / shading.
Resistance Expenses

Battery voltage is the operating voltage from solar cell module panel, when the battery is connected directly to the solar cell module panel. For example, most 12-volt battery, the voltage / battery voltage is usually between 11.5 to 15 Volts. To be able to charge batteries, solar cell panels should operate at a higher voltage than the voltage of the battery bank.

The highest efficiency is when the solar cell panels operate near the maximum power point. In the example above, the battery voltage should be close to the voltage Vmp. If the battery voltage falls below Vmp, or rises above Vmp, then its efficiency is reduced.

Sunlight Intensity
The greater the light intensity will produce a proportionately large currents. As the following figure, the level of sunlight decreases, the shape of the IV curve shows the same thing, but moving downward indicating decrease in flow and power. Voltage is not changed by a variety of light intensity.
The temperature of the solar cell panel

As the temperature increases above the solar cell panels standard normal temperature 25 degrees Celsius, the panel module solar cell efficiency and voltage efficiency will be reduced. The figure below illustrates that, like, the cell temperature rose above 25 degrees Celsius (the temperature of the solar cell module panel, rather than air temperature), IV curve shape remains the same, but shifted to the left in accordance with the temperature increase solar cell panels, resulting in voltage and power smaller. Heat in this case, is the electrical resistance to the flow of electrons.

For that airflow around the solar cell module panel is important to remove the heat that causes the temperature of high solar cell panels.

Shading / shade / shadow

Solar cell panel, which consists of several silicon in series to produce the desired power. One silicon resulted 0:46 Volt, to form a solar cell panel 12 Volt, 36 diserikan silicon, the result is 0:46 Volt x 36 = 16:56.

Shading is where one or more of solar cell silicon cell panels covered from sunlight. Shading will reduce spending power from solar cell panels. Several types of solar cell module panel is badly affected by shading than others. The table below shows the effects of extreme influence of shading on a single cell from a single crystalline solar cell module that does not have an internal bypass diodes. To overcome these solar cell panels installed bypass diodes, bypass diodes for current flows in one direction, preventing flow into the silicon shadow taxable.

It should be noted in the installation is for the solar cell panels are not blocked / shading.

* Data taken from the book Design and Installation Manual photovoltaics