Hi @fabioluzo, Thank you for your interest in our products.
Your calculations are very thorough. However, please note that the power per unit area is calculated based on the area of the solar cells, not the total area of the solar panel. This may cause some discrepancies in the calculation results.
Hi, the efficiency for solar panel is calculated for all area of construction, not only the solar cell.
That’s the way you can find on brands like Canadian, Longi, Trina, etc. So, only for cells of course you can have a higher efficiency.
But we are talking about solar panel efficiency, as a whole, not only cells.
Please, look at this comparison on the Bluetti website (it’s in portuguese, but you can translate if needed): it says that the “Bluetti solar panel has a solar panel efficiency as 23.4%, while other brands has only 15%”:
Hi @fabioluzo, We have reconfirmed that the efficiency of the solar panel is indeed calculated based on the area of the solar cells themselves, and the frame and gaps should be excluded. This aligns with the consensus among all solar panel manufacturers.
As for the comparative efficiency, it is based on the test results of third-party samples we have procured.
Hi @BLUETTI_CARE , it’s not like this.
Just check any solar panel datasheet.
Example, for this one with datasheet attached here:
The 570W model, quite common on the market, calculating:
Area of the solar panel: 2.278 m x 1.134 m = 2.583 m²
570 W / 2.583 m² = 220.7 W/m².
Efficiency: 22.1%.
That’s the way it must be calculated. Makes no sense to use only the solar cell. The good quality, the best products have relation with the way they are built, reducing the area of frames and gaps.
Of-course that the solar cells of this solar panel from Canadian has a higher efficiency compared to 22.1%. But people use the solar panel as a whole, not just the solar cell.
Solar panels manufacturers do not advertise their solar cells efficiency, because that’s not the right way to do it.
The 23% Bluetti advertises is not fair for customers to properly evaluate it.
Hi @fabioluzo, Thank you for your attention and suggestions regarding this matter.
Our measurement methods comply with industry standards and local laws and regulations.
They may differ from the examples you mentioned, but this does not mean our data is without significance.
We have also forwarded your comments to our product manager for reference.
Hi @BLUETTI_CARE , my comments are related to the advertisement of Bluetti solar panels and efficiency.
Customers buy solar panels, not solar cells. So it’s not fair to advertise that the solar cell is so good if the final product, the solar panel, has a much lower efficiency based on total area.
It’s like if some car manufacturer advertises that the engine alone is better. However people buy cars, not engines alone. So the final product, the car, must be efficient, not so heavy, with overall mechanics that supports its quality. The engine alone itself is not enough to evaluate the car performance.
I hope you understand it. Of course Bluetti selects the best components, but what matters in the end is the final product.
Hi @fabioluzo, Yes, we understand your perspective, and we are also committed to providing more efficient products.
We have forwarded your comments to the R&D department. We believe we can develop solar panels with higher efficiency.
Thank you for your attention to our products.
I concur with @fabioluzo that the total area should be calculated and not solar cells directly to account for external factors such as thermal expansion, wiring, build material such as metal causing a panel to get hotter, glass reflecting light away, delamination/peeling issues on a foldable panel, etc. Additionally the type of materials the cells are made out of can make a huge difference as well in terms of efficiency. Surface area means nothing if the cells are subpar.
I was never a fan of marketing buzz words such as “up to 23% efficient” because the average consumer cannot translate what it means without researching. On the surface it sounds like the panel is highly inefficient! What if I told you your phone battery will provide you 23% power. That does not sound great. Of course we know technically it refers to the conversion rate, but without providing context, the meaningfulness is lost.
A better idea would be to simply advertise that the panel is capable of producing up to its rated capacity when the panel has achieved solar alignment and there are no other environmental factors involved such as haze or higher temperatures reducing efficiency. This way people know the only way I am ever going to get around “350” watts from my Bluetti PV350 panel is I need to check that my panel is aligned. You could develop a solar alignment tool in house that is attached to the unit itself or sewn into the zippable pouch again so it can’t fly off or get lost. Then all someone would need to do is attach the alignment tool to the center of their panel and see how close the dot is to the center for perfect alignment. It also educates users that you can’t just lay a panel flat even in the summer and get 350 watts out of a panel. You could also advertise that the 23% is the CONVERSION rate and not the efficiency rate and simply state that the panel can convert up to 23% of sunlight energy into power, not that its 23% efficient.
Finally you may want to advertise a solar panel’s shading advantages as well, such as if it has better bypass diodes or can capture light better. If anything as a consumer, I’m never worried about how much power I get when its sunny out, I’m more worried about what i DONT get when its cloudy out. If anything shade performance is the most important factor, so the panels ability to generate voltage when its partially shaded is a very nice thing to know. Most of the cheaper panels that sell for under $200 often have a lower operating voltage like 18.5V which means they perform more poorly than a Bluetti panel with a higher starting voltage. So you could advertise that since the cells can capture more light, its voltage is higher, and as a result its potential is greater.
