When you are looking to buy a solar PV system for your home or business and have received multiple quotes from different solar vendors, one of the key factors that will set the solar vendors apart is the type and brand of solar PV panels they offer and the quality of other components of the solar panel system.
The solar panels are one of the most critical components of any Solar PV system installation along with the inverter. Please note that the solar panel we’re referring to here is the one that’s used to generate electricity, not generate hot water. The solar panels that are used for electricity generation are also known as solar PV modules. With that clarification out of the way, let’s take a look at some of the key factors to consider in selecting your solar panel for your solar PV system.
Factors to Consider
1. Efficiency of the Solar PV Panel
The efficiency of the solar PV panel, in simple terms, is the conversion of solar energy that falls on the solar panel into electrical energy. The efficiency of a solar panel is usually expressed in percentage. So, for example, if the solar panel converts half the solar energy that falls on it into electrical energy, then the efficiency of the said solar panel would be 50%. In real-world conditions, the typical efficiency of a solar PV panel ranges from 15% to 21%.
A high-efficiency solar panel would require less space to generate the same electrical output when compared to a solar panel with lower efficiency. For example, a 330 W high-efficiency solar panel would require less space to install when compared to a 330 W low-efficiency solar panel. Simply put, a low efficiency 330 W solar panel would be larger in size than a high efficiency 330 W solar panel.
The disadvantage of a high-efficiency solar panel is that they tend to more expensive than a low-efficiency solar panel. So, if the rooftop area is at a premium, then you may want to go for a high-efficiency solar panel. Otherwise, if you have plenty of rooftop space for your planned solar PV system, then you may want to go for a good quality solar panel with an efficiency of 15% or above.
Also, the efficiency of a solar panel varies with factors like temperature, low-light conditions, etc. Contrary to what most people think, the efficiency of a solar panel decreases with an increase in temperature. So, in hot weather conditions like in Chennai, it would be best to choose a solar panel where the efficiency loss is only marginal with an increase in temperature. The parameter you have to look for is the temperature coefficient of the solar panel. This will be mentioned in the datasheet of the solar panel.
Also, certain types of solar panels perform better than others in low-light conditions, like when it is cloudy. But these solar panels tend to be costlier than others. If your solar vendor says that a particular type of solar panel is better than others, ask them to provide actual generation data for at least 12 months for different types of solar panels, so that you can compare them yourselves. With the cost of the solar panels and generation data, you can then find out the cost per unit of solar energy generation. You can then choose, depending on your requirement, to either go for the budget solar panel (lowest cost), the value solar panel (lowest cost per solar energy generation), or the premium solar panels with the highest solar energy generation and best efficiency.
2. Cost of Solar Panel
When comparing solar panels for your solar PV system, one of the metrics you would want to calculate is the cost per watt. As you may have already guessed, the cost of good quality solar panels will generally be more than lower quality solar panels. Please note that the cost per watt we are referring to here is only for the solar panels (solar modules) and not for the entire solar PV system which includes other components like structure, wires, inverters, batteries, etc.
We would not recommend choosing a solar panel based on cost alone. As mentioned earlier, good-quality solar modules generally tend to cost more than lower-quality solar panels. However, some vendors may be offer discounts on good quality solar panels due to some special deals or because of the volume advantage that some vendors may enjoy. When you are comparing solar panels, please ensure that you are making an apples-to-apples comparison when it comes to cost, panel quality, availability, warranty, service, etc.
If you ever come across a deal on solar panels that you think is too good to be true, then it probably is.
3. Solar Panel Quality and Warranty
It may be difficult to deduce the quality of solar panels from just the quotes that you may have received from local solar vendors. But there are other ways to determine the quality of the solar panel mentioned in the quote.
(i) Unbiased online ratings from verified buyers – Online reviews from other buyers can help us determine the quality of solar panels. The downside is that some of the reviews may be fake. Only take into consideration reviews from verified buyers. You can also ask your solar vendor to provide you their customer references and you can talk to the buyers directly to gauge the quality and performance of solar panels used. Or you can simply go through the unbiased solar panel reviews that we’ve collected from verified solar buyers in Chennai. Please consider the reviews from solar buyers whose solar panel installation is at least 1 year old.
(ii) Performance warranty – The performance of a solar panel reduces over time. This means that a solar panel generates less power in its 20th year after installation when compared to its first year of installation. Typically, a solar panel’s performance warranty will guarantee 90% production, or 90% of the solar panel’s power output rating for the first 10 years and 80% for the next 15 years. Please note that the solar panel performance warranty is different from the product warranty of solar panels. As with most warranties, a greater number, whether in terms of better production percentage or longer years, is beneficial and points to a better quality product. Without getting into too much detail, it is usually difficult for a homeowner or small-scale solar PV system owner to prove to the solar panel manufacturer that their solar panel is not meeting the numbers mentioned in the performance guarantee. Generally, the performance warranty is considered less important than the product warranty of a solar panel.
(iii) Product warranty – The product warranty of a solar panel covers the defects or issues in workmanship and materials – like manufacturing defects, premature wear & tear, etc. If your solar panel suddenly stops working, it might be possible that the said solar panel is a defective piece and should be replaced by the manufacturer or the solar vendor under the product warranty.
The product warranty of a solar panel is considered more important than the performance warranty. The product warranty is usually for a shorter time period than the performance warranty of a solar panel. Typically, the product warranty for a solar panel is from 10 to 12 years. Some manufacturers offer solar product warranty for more than 20 years. This shows their confidence in their solar panel and their intention as a company to remain in the solar business for the long term. Since solar panel warranties typically range from 10 to 25 years, it is important to choose a solar panel manufacturer who has a good track record, presence in India, and strong financials that will enable them to stay in the solar business for a long time.
Some of the question to consider regarding the solar panel warranties are: what will happen to the claim on the product or the performance warranty if the solar vendor or the manufacturer is not in business anymore; what happens to the warranty if the solar manufacturer does not have an office in India or decides to shut down their operations in India?
(iv) Solar Panel Quality Certification – Solar panels are subjected to rigorous testing before they are given approval for installation. The tests are done to determine the quality of the solar panel and also to ensure that the solar panels conform to the required safety standards.
There are different organizations that provide certifications for solar panels related to quality, performance, and safety. You will find these certifications listed in the solar panel’s datasheet. Some of the well-known organizations that certify solar panels include the International Electrotechnical Commission (IEC), Underwriters Laboratories (UL), and Bureau of Indian Standards (BIS). These organizations certify the solar panel for different parameters like fire safety, corrosion testing, etc.
Please ensure that the solar panels you choose have the necessary certifications as defined by the various regulatory bodies in India like the Ministry of New and Renewable Energy (MNRE).
4. Replacing a Defective Solar Panel
Please check with your solar vendor regarding the procedure to replace any defective solar panels. Some of the questions to consider include – will the solar vendor themselves replace the defective solar panel or do you have to contact the solar panel manufacturer?; are there any labor and shipping costs involved in replacing the defective solar panel?; how much time will it take to replace the defective solar panel? etc.
5. Power Tolerance of a Solar Panel
A solar panel rated at 100 Watts is expected to give the same output (100 W) under standard test conditions. There is one parameter in the datasheet of the solar panel you might want to take a close look at and that is the power tolerance value. Different solar panels may have different power tolerance values. The datasheet may mention a power tolerance of +/- 5%. This means that the solar panel can either give an output of 105 Watts or 95 Watts. You may want to choose a solar panel that has a very low (or zero) ‘negative power tolerance’ value or choose a solar panel that has only a positive power tolerance value (for example, only +5%, no negative value).
6. Profile of the Solar Panel Manufacturer
It is important to go through the profile of the solar panel manufacturer to ensure that they would still be in business to support the product and performance warranties of your solar panel since these warranties are typically for a period of 10 to 25 years.
Ask for the solar panel manufacturer’s profile which may include details about their overall installations so far, their manufacturing facilities, market share, their dealer or distribution network, quality certifications, funding, investors, the financial performance of the company, etc.
Some manufacturers just buy solar panels from other companies and self-brand them. Some manufacturers import solar cells and outsource the process of assembling the solar cells into solar panels to other companies. If this is the case, then you want to know how the company will support you in case of any fault in the solar panel.
Choosing the Best Solar Panel in India
There is no definitive answer to the question – what is the best solar panel in India? As we’ve seen, the best solar panel is the one that best fits your requirement. Many factors have to be taken into consideration in choosing the best solar panel like price, efficiency, quality, manufacturer profile, and other solar panel specifications like temperature co-efficient, power tolerance, etc. Also, certain factors like your budget, space availability, availability of panels with your local solar vendor, service support of the manufacturer at your location, etc. also play an important role in selecting the best solar panel for you.
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