Different types and brands of solar panels are available in the market.
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Do you wonder what the difference between them is?
Do you feel difficulty in understanding the technical language when you look at the specifications?
If yes, then you are at the right place to understand the difference in simple words and make sure yourself that you are not spending a significant amount of your hard-earned cash on a lemon.
Solar panels have several characteristics. Following is the list of most important specifications that all panels have, but the values differ greatly.
1. Solar Panel Test Conditions:
As we all know, panels are tested in laboratories for efficiency under Standard Test Conditions which are as follow:
The temperature of the cell should be 25ºC.
Solar irradiance level should be 1000W per square meter. (This is the amount of light energy falling on a given surface at a given time.)
Air mass 1.5 spectra.
If you do not fully understand the parameters above, then don’t worry, the main point to consider is, when the panels are on your roof, all these conditions will keep on changing. So, you need to look at the NOCT (explained in the next point).
2. Solar Panel Nominal Operating Cell Temperature (NOCT)
NOCT is the temperature reached by open-circuited cells with irradiance set at 800W/m2, ambient temperature 20°C and speed of wind at 1m/s. The approach is used to test the panels in somewhat real-world conditions. Because panels usually operate in hotter or colder conditions, different irradiance levels compared to what the Standard Testing Conditions of the panel are.
Typically, the NOCT value is 45ºC. You should look for NOCT value to be 45ºC or lower because the lower value means the panel will stay cooler under real conditions. The more the panel stays cooler, the more efficient it would be.
3. Solar Panel Temperature Coefficient
The lower the temperature coefficient, the much better that module will undoubtedly carry out as temperature increases. The lower temperature coefficient is necessary for all areas, not merely warm environments. When the sunlight is shining, rooftop temperature levels can quickly go beyond 77 ° F even with ambient temperatures below 50 ° F. You can compare the temperature coefficient of different panels by their respective information sheets.
4. Solar Panel Tolerance
Solar Power Tolerance is a measure of the amount of electricity a panel can generate above or below its rated capacity at any time. It’s often ±5%, which means the panel could produce 5% less or more than the rated capacity. So, it is something that should be kept in mind.
5. Solar Panel Warranties
Solar Panels are designed and made to operate in a real environment, which means panels need to deal with changing hot and cold weather conditions, wind, UV radiations. The standard warranty for panels is 25 years. It is quite a long time, but you should keep in mind that whether that retailer or manufacturer would be around or in business for such a long time to honor the warranty. So, we suggest to go for reputable, financially sound and stable companies and do check the historical track record.