Solar Panels in the basic sense work by converting available sunlight into usable electricity. The way we define this power is by watts. Watts are made up of amps and volts. Different panels have different ratings for amps and volts, and it is helpful to understand what these numbers mean when you are looking at a system. You can imagine amps as the amount of electrons, and the voltage the amount of pressure pushing those electrons.
Equation: Watts = Volts x Amps
A solar panel is made up of different components as seen in Model 2.1.1. Not all panels will have these specific components in the specific locations, but generally our panels have this.
Solar Cell (126.96.36.199): The solar cells can be seen on front of the solar panel. They vary in color and appearance based depending on the type of cell. The type of cell generally defines what kind of panel it is, for example monocrystalline, polycrystalline, amorphous, etc.
Frame (188.8.131.52): MostRenogy Solar panels have an aluminum frame, but depending on the type of panel frame type can vary.
Junction Box (184.108.40.206): The junction box is generally located on the back of the panel. It contains bypass diodes to help with power loss due to shading. Also it serves as a connection and a holder for the panel wires.
Wire (220.127.116.11): Our Renogy solar panels come with standard PV wire that is weatherproof and insulated (as long as there is no exposed copper wire).
MC4 (18.104.22.168): At the end of the PV wire is a MC4 connector. This MC4 connector is standard in the PV industry, is weatherproof and serves as a connection point to our other MC4 cable, such as an adaptor kit.
Specification Sheet (22.214.171.124): The panel’s specification sheet will tell you the electrical characteristics of your solar panel. It is very important when sizing systems.
MONOCRYSTALLINE VS. POLYCRYSTALLINE
Monocrystalline solar panels are slightly higher in efficiency than polycrystalline panels because each utilizes a different manufacturing technique. A monocrystalline cell consists of a single crystal ingot, whereas a polycrystalline cell consists of a growth containing multiple crystal structures. Both types of cells are made from silicon ingots, but the purity requirement of the silicon is higher on a monocrystalline base. Therefore, monocrystalline panels are more efficient, and thus, more expensive. By using a single cell, monocrystalline based silicon allows the electron greater freedom to move, so less energy is lost and higher efficiency is created. Most monocrystalline cells peak at 22% efficiency, whereas most polycrystalline cells peak at 18% efficiency. Monocrystalline cells are a dark blue almost appearing black, and polycrystalline cells are blue.
Even though this is true, there is a common misconception that monocrystalline solar panels will actually perform better than polycrystalline panels even in situations where they have the same wattage. This is not true. A 100W Mono Panel should perform just as well as a 100W Poly Panel, assuming the electrical characteristics are very close. A customer’s decision should be based on the price, the dimensions, and the color. Also due to common misconception, Poly and Mono panels should perform the same under low light conditions. They also should perform the same under high temperatures.
SOLAR PEAK HOURS AND IRRADIANCE
It is important to use the peak hours with the wattage of your system to calculate how many watt hours your system produces in a day. You can view peak sun hours as an average, as basing power off the hours of daylight during the day isn’t sufficient. The reason why is because sunlight in the morning and evening will not produce as much radiation as solar during midday. To calculate each states peak hours, the radiation is averaged based on the highs and lows and also other factors such as what is mixed into the atmosphere.
As you can see from the data gathered Model 2.1.2, the level of irradiance or W/m2 varies throughout the day. The panels output is directly related to the W/m2 at that given time. Most solar panels are rated at 1000 W/m2. If the irradiance level is let’s say 500 W/m2, like it is at 8am in the graph, then you should expect half the output (50%). Because of this fact, the solar peak hours of your state isn’t how long the sun it out, but an average from the lows and the highs so that it can be a reliable number in calculating energy generation.