Research Solar

Top 5 things to consider when buying solar panels.


Solar Panels, also known as solar modules in the industry are the heart of the solar PV system. They convert the sunlight into usable dc electricity. Solar panel selection can be more technical and trickier part for many. Thus, we discuss 5 things to consider when buying your solar panels.

The parameters to consider, in selection of solar panels that shall meet your long-term output goals are as following:

1. Type of Panels

There are broadly two types of panels:

  • Monocrystalline Panels
  • Polycrystalline Panels

These are classified based on the solar cells used in its make.

Monocrystalline Panels use solar cells that are cut from a single source of silicon, making it very efficient. They can yield higher outputs.

Polycrystalline Panels,also known as multi-crystalline panels,have solar cells that are blended from multiple silicon sources, making it relatively less efficient. Though they are widely manufactured and used for their yield and economy value, in long run, monocrystalline panels will be more promising.

2. Efficiency

In order to understand the efficiency factor, we need to answer the following question first:

What defines an efficient Solar Panel?

The efficient solar panel is defined as the power a pv panel can generate with respect to the space it occupies.

The solar panel efficiency is the ratio of power capacity of the panel (kWp), with respect to the size or area of the panel (m2).

It is evident that efficiency rating of the panel has to do with the space it shall occupy on your rooftop. The output quality is no-where the determining factor.

Thus, if you have enough space for setup, you can use panels having less efficiency. But if you have a space constraint, you would have to go for panels with higher efficiency values.

You can get to know the efficiency of the panel from its datasheet.

3. Thermal Co-efficiency

Thermal coefficient of solar panel is often, an ignored parameter which should be of a must concern for panel selection. To understand thermal co-efficiency, let us first talk about the ambient temperature and then understand how these two are related.

With change in the surrounding temperatures over the day, the solar panel temperature also changes. The temperature of the panel that varies with its surroundings is also known as the ambient temperature. It plays a critical role in quality output power of the solar panel.That means at change in weather temperatures, the panels will yield different output power.

You can determine the effective output of panel at different temperatures considering the temperature coefficient of the panel. Thus, we can define the temperature coefficient of the panel as the rate at which the output power generation will vary with respect to the panel’s ambient temperature. You can get this value, again from the datasheet of the panel.

Further taking an example,if rated capacity of a solar panel is 25oC, then a temperature coefficient of -0.45 %/oC indicates that, with every 1oC increase in the temperature over 25oC, will cause a 0.45% decrease in the power output. Similarly, with every 1oCdecrease in the temperature below25oC, will cause a 0.45% increase in the power output.

As you can see in the following table, as the temperature increases, the effective panel output also decreases.

The ideal ambient temperature range for efficient output power ranges between 20-25oC. The rated capacity of solar panels is generally calculated at 25oC.

So, the more Sun, is NOT really merrier in case of Solar Electricity.

4. Degradation Rate

Any electrical equipment ought to degrade with time. As per the thumb rule, on an average, the panels degrade by 1% every year. This denotes that after twenty years, the panels would be capable of producing 80% of the rated power.

But moreover, the efficiency decreases more in extremes of climate, snow, dust and wind-loads. So if your geographical location is prone to any of these, you would’ve to take added equipment and timed maintenance as precautionary measures for the same.

The good news is, the panels degradation factor is coming down with new research & technology. You can find this valueas well in the datasheet of the panel.

5. Warranty & Depreciation

Warranty & Depreciation have nothing to do with the output power of the panels. Yet they are an important factor to be considered for our financial transacts.

Generally solar panels last for more than 25 years. Thus, the manufacturers provide two types of warranties:

1. Product Warranty

  • It refers to the time upto which a manufacturer would repair or replace the panel and its damages.
  • It ranges between 10-12 years.

2. Performance Warranty

  • It refers to the power performance of panels based own their degradation factor (as discussed in the previous point) over the years.
  • It ranges between 25-30 years.

You find this too in the panel datasheet.

Talking about depreciation, there is no standardization in form of rebate or any other transferrable assetfor solar panels. This pertains to the solar panels agingprocess. However, one can avail a lot of indirect benefits, incentives and subsidies that the government offers to promote solar sales.

Summing up the Selection Process

With more researches and advancement in technology used to make solar panels, the efficiency and power ratings of the solar panels are also increasing. The prevailing technology trends that meet the commercialisation include: Half-cut Cell, PERC, Bifacial, etc.

However, you can choose your panels considering your budget and ROI calculations. Just make sure you check all the discussed points in this article, when buying solar panels.

To avoid all this hustle, just opt for PIXON solar panels. You are ensured of Best Quality Output and Efficiency.

Call us at: 1800 108 8800.