A guide to solar panel quality:x important factors you need to know

A guide to solar panel quality10 important factors you need to know

Getting a solar-powered system is growing more and more popular these days. Solar panels are one of the most vital aspects of a solar-powered system.Regardless of where you install the solar panel — the roof or ground, its quality becomes an essential part of choosing the best solar panel for your property.But sourcing solar equipment can be challenging. Especially due to the complex solar panel production cycle, which involves various stages such as selecting raw materials, cell assembly, and module assembly, each stage has critical quality parameters that must be monitored. 

Regardless in which country your solar panels are produced, solar panel defects occur on a regular basis.In this article, we’ll tell you how to choose a quality solar panel.


Look for trustworthy and certified manufacturers

There are over 350 manufacturers in the market of photovoltaics. Some make panels better than others.Straight up,you can choose the top brands on the market.We ranked the ten best solar panels for 2023:

  1. LG — Ranked as one of the best overall solar panels. 
  2. SunPower — is ranked number two due to the high efficiency of its panels. 
  3. Panasonic — Ranked number three due to the high efficiency of their panels during the hottest times of the day. 
  4. SilFab — ranked 4th for offering one of the industry’s more robust warranties. 
  5. Canadian Solar — ranked 5th for being a quality and affordable option for solar panels.

But the price of top brands will be higher than other brands.Some brands also have very good quality, but lack visibility,fortunately you can get it for a lower price.But before buying the panel, you need to examine the manufacturer.

When reviewing manufacturers for solar products, first determine if the manufacturer is producing solar panels according to industry standards. This can easily be found out by requesting the common pv product certifications. After receiving the certifications, verify the authenticity of the pv certificate on-line at for instance TUV Rheinland.

Certifications on your solar panels provide the standards for the profitability and security of your investment. All standard solar panels should be certified. Common solar panel (pv) certifications are CE/J-PEC/TUV/INMOTRE.

You can also check the following additional details of the manufacturer:

  • How long has the company been in the market?
  • How much warranty are they offering?
  • Reviews in the public forum
  • After-sales service


Check datasheet

The datasheet contains all the technical specifications of a panel. Here is what you want to pay attention to.

Here’s a our company sheet :

  • CURRENT MPP Impp (A)

Learn more:400 watt solar panel datasheet


Brand’s technologies

Each brand has something special about them.Sometimes the strong sides of a panel are mentioned on the first page of a datasheet.Choose the panels which meet your need for electricity.


Visual inspection

During the visual inspection each solar panel is reviewed by an independent certified testing agency for defectives, including scratches, glue marks, montage frame and anything that is deviant.


Standard test conditions

Production numbers in the datasheet come from testing solar panels at standard test conditions (STC) to measure their performance. STC specifies a temperature of 25 °C and an irradiance of 1000 W/m2 with an air mass 1.5 (AM1.5) spectrum. Note that STC numbers don’t always reflect how well a panel performs in the real world.


Solar Power Tolerance

As solar panels are being manufactured, some unavoidable variations that impact power output are introduced.  A smaller tolerance means that the solar panel is more consistent in its output. It’s best when panels have a positive tolerance.5% is the tolerance range of quality panels for tolerances.An example, a 400 watt solar panel that has a +/=5% solar power tolerance could produce anywhere from 380 watts to420 watts under ideal conditions.


Temperature Coefficient

This is the amount of energy the solar pales drop when at a specific temperature.Although solar panels are designed to love the sun, high heat can decrease a solar panel’s capacity to generate solar power. A temperature coefficient below 0.5% is good. 

  • Average coefficient – 0.50% – Reasonable performance
  • Lower Coefficient – 0.30% – Best performance
  • Higher Coefficient – 0.70% – Low Performance


Efficiency of a Solar Panel

The higher the efficiency of a solar panel rating means that the solar panels are going to produce more kilowatt-hours of energy per watt of solar power capacity. Because one solar panel with high efficiency can generate more solar electricity than a similarly sized solar panel with a standard with the standard efficiency of a solar panel rating, the efficiency of a solar panel is particularly important if you have limited roof space and large energy bills.

 In 2022 the best panels were just shy of 23% and we’ll probably cross this threshold in 2023.


Evaluate durability

The data sheet lists the dimensions, weight, and resistance to environmental factors such as humidity, salt mist, UV radiation and mechanical stress. Mechanical tolerance becomes important when you live in places where extreme weather conditions are common.


The Quality And Length Of The Panels Guarantee

If there is a problem or defect, then your first line of defense is the warranty. Remember that a good warranty covers labor, parts, and shipping.

Since most solar panels have a 25-year warranty, the parts and labor portion becomes very important.Several of WinSeven SOLAR’s panels come with a 30-year warranty.


Test Solar Panels

4 Ways to Test Solar Panels: Output, Wattage & Amps

  1. Test a Solar Panel with a Multimeter
  2. Test Solar Panel Amps with a Clamp Meter
  3. Test Solar Panel Output with a Solar Charge Controller
  4. Measure Solar Panel Output with a Watt Meter

If the performance of your array seems suspiciously low, contact your solar panel manufacturer.



Checking the quality of the solar panels before putting them to use is very important to make sure you detect the defects.

A first step is to select a solar panel manufacturer that produced certified solar panels. This is a first simple step to be sure that the solar manufacturer produces solar panels according to the quality standards.

The next step is determining the quality of the solar panels. The PV quality requirements need to be included in the manufacturer’s contract.

Finally, after the solar panel manufacturer has produced the solar panels according to your quality requirements, independent testing needs to be performed.