Let’s face it, we all love a good deal. Doubly so when it comes to expensive investments like a solar power system. But, even though scoring a good deal will help you save a few bucks (and give one helluva kick), it may come at the cost of your long-term interests.
For example, a study on solar panel installations conducted by DuPont in 2019 found that even though the amount of PV installations had increased, so had the number defects.
33% of the panels had problems that affected their performance. Panel backsheets and solar cells comprised 14% (each) of the problems, while encapsulation errors were detected in 4% of the panels.
Unfortunately, the number of defects seems to be keeping pace with the rise in solar panel popularity. And, the lower priced stuff is usually the one that’s pointed out here. Compromising on quality to save a few bucks in the short run can have cascading consequences in the years to come.
The long and short of all the problems your solar panel can encounter is that they won’t produce as much power as advertised for as long, or, will fail well before their expiry date. But, just what problems lead to such performance losses? Here’s a short description of the most common kind.
Hot-spots in Solar Cells
No electric system is perfectly efficient. Most solar cells are capable of converting 15% and 23% of the solar energy falling on them into usable power. Electricity can be lost by sunlight reflected from the glass encasing, or, by resistance within the solar cells and wiring underneath.
Hotspots themselves are caused by other issues. Low quality solar cells, bad soldering, cracks, mismatched parts etc all of which can cause heat buildup, leading to hot-spots that damage the panels. In extreme cases, hot-spots can also cause the panels to overheat and catch fire.
Hot-spots are easy to identify as they appear as distinct burn-marks on the panels.
As DuPont’s report points out, backsheet defects are on the rise and pose a strong risk to solar purchases. The backsheet forms the foundation of a solar panel and on which a PV array sits. Any damage to the foundation can cause the solar cells to start malfunctioning. There are five kinds of backsheet defects —
- Yellowing: Yellowing happens when the backsheet polymer starts to break down and is usually observed on the air-side part of a solar panel. Cell side yellowing is more serious, although less common.
- Cracking: Cracking on the backsheet, usually is visible as long cracks. Air-side cracking is more common than cell-side cracking.
- Delamination: The most serious defect a backsheet can have. Delamination means the backsheet polymer begins to peel off, exposing the encapsulant to the elements. Fortunately, delamination is rather rare.
Poor Quality Solar Cells
Damage to a panel’s exterior or mounting system can be easily repaired. However, if the PV modules themselves are defective, the panel will need to be replaced. The problem lies with identifying issues in solar cells.
Sometimes, they are easy to detect as visible deformities form on the panel surface like cracks and snail trails. But, what if there’s no external indicator and your solar power system isn’t performing as expected?
Is it the cells, the bussing, balance of system or inverter that’s causing the problem? Solar cells are susceptible to micro-cracks that cannot be seen which may exacerbate performance issues.
There really is no way but to go with a properly vetted solar panel manufacturer to ensure your panels are free of such errors.
Mismatched Cells Connected in a Series
A solar panel consists of an array of photovoltaic cells connected together in strings. The total output of a panel is essentially the sum of all the cell’s voltage and current. But, since the voltage of a panel must remain constant, it automatically defaults to the lowest value. So, if there’s a significant difference in output between cells in a string, the output of the entire string falls to its least performing part.
Mismatched solar cells is a common issue in low quality solar panels and only grows with time. Tier-1 manufacturers usually sort their PV modules before installation to ensure mismatch losses are minimized.
Notice how all the problems with low quality solar panels reveal themselves after they’ve been installed. This means more headache for the buyer who has to spend time and sometimes even money to get their defective panels replaced.
Such unfortunate episodes can be avoided with a little upfront planning. BidMySolar was founded with the aim of helping buyers make the most informed decision when investing in solar power. Our process ensures that the buyer’s interests are always prioritized and you get the best combination of price and quality for your specific requirements.