How half-cut solar cells work in shaded conditions.
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- čas přidán 13. 03. 2021
- www.gses.com.au/
Half-cut cells are uniquely structured for improved performance under shaded conditions than their standard, full cell counterparts. But do you know what their outputs will be as shading conditions change?
Shading conditions vary over time, and whether the shade comes from cloud cover, debris on the modules, or neighboring structures or trees - this video will help you to better understand the technology for use in your future Solar PV designs.
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This is basically the only video (or article) I've found online that wasn't a bunch of half truths and misconceptions regarding solar panel shading, but actual practical data applicable to the real world.... Thank you.
Theoretically, I do agree. Today though, I put two panels on the ground, a lightbulb, and started testing with shading manually. The outcomes are unexpected. The output didn´t want to go down much, unless both halves were shaded. Standing above panel didn´t do much, only solid cover over both (parts) of the panel lowered the output. And so I begun to be somewhat skeptical.
This is the best video explanation I have seen about the working of diode in solar module with IV curve interpretation. Cleared all my doubts about IV of half cut cell modules. Thanks!
Also can you make a video on how diode becomes forward biased when a cell is shaded in a string please?
THIS is the first site I've found that sufficiently explains to my EE brain how the diodes in half-cut function somewhat (potentially) better than full cut and the scenarios that have to play out to make it worth it. I wish I could give more than one thumbs up to this. bravo.
Good info 👍
Buying a half cut is not enough... Orientation of panel also matters when it's installed in site prone to shading...
Something new for me..😊
Thank you! Very clear and logic explanations with good examples.
Great no nonsense video! You guys should make more such videos. Thanks a lot.
Our pleasure!
Great explanation!
Very valuable info and well presented. Much appreciated.
Great info that was not included in the salesdeal of my 22 new AEG-AS-M1202B-H(M6)-370W Mono Full Black/ Half cel panels icw with Solaredge S500B power optimisers. New subscriber.
Amazing video, thank you
This is good if you are using Microinverters per panel, or if you have connected it in Parallel. Only two panels in series, will have huge power reduction, if MPPT cannot track the MPP of the whole string.
So, as we know, one module is Divided into 3 strings using By-pass diodes, and those 3 strings are cut and connected in Parrallel. The problem even with two panels is, if there is some sort of shading in one part of the panel, 1/6, and if the MPPT controller is not able to lower its voltage. All the string will start working at 50% of the power, and if there is no proper sweep function in the MPPT controller, you will be stuck at 50% power unless that shaded part is cleared.
Either that, or you will need a really good MPPT controller to properly track the MPP. From my setup, where I use two Half-Cut panels in Series. I get shading from a small wall next to the panels till 9AM in the morning. In somedays, the MPPT tracks 68V, and I get full output from both the panels, except that one string. However, some days, it keeps tracking at 84V, which makes the panels run at 50% of its power, when only one of the strings is shaded 1/12.
If I talk in Watts, the total watts 1100 Watts, divided by 1/12, gives 91.6W each. So in my case, I should loose, 2/12 worth of power if its shaded on one part, which is 183.3W. However, due to MPPT not able to track the MPP, I am stuck at generating 6/12 worth of power, instead of 10/12. Which equats to 549.6W instead of 916W. Thats a 50% loss in power production, instead of 16%.
So its better to avoid shading or get a really good MPPT controller, or use a Microinverters, or individual MPPT per panel.
Great video! I learned a lot.
Thank you. That was very clear.
Very well made video!!
You've earned a new subscription !
Great video 👍
Welcome aboard!
Omg. This is one of the best solar vids out there!! Thanks a ton for doing it!!
Thank you so much for this video, tracing the current through the sections of the panel was so informative
Hi ,sir please make a video during night condition, how diode bypass current or block
Great video 👍🏼
Glad you enjoyed!
Thank you! Among the very best PV explanation videos I've seen. My pleasure to recommend your chan to all my pV friends.
Thanks Andris! Let us know if there are other topics you would like us to cover :)
@@GSES_Solar_Training Hello from the other side of the globe! So nice to hear back from you! There is indeed a topic. Could you kindly help educate us, users, on Panel Level Monitoring. using Solar Power Optimisers? Pros and Cons? And my very situation-specific question - does the string inverter need to communicate with the power optimisers for them to work their magic? I am being offered optimisers and the string inverter from different brands, so they won't be able to "talk". Thank you!
Great video. That last example was what i was wondering. Is it expected that the string inverter with global MPPT will still attempt to sweep the current(?) and then notice that, with all other 8 modules unshaded, dropping the current (to recover some output on the affected module) will not be worth it since it would cut the other modules' output in half? Hypothetically if all modules had effectively similar shading, the MPPT would change the current to at least get something out of them? What about scenarios with not though minimum voltage from the string?
There's just so many variables to the shading situation
I have 9x 550w half cut solar panels in a string (4.95kw) ground mounted.
And i experience multiple types shading in the winter. Light scattered shading from a tree, total shading from the house (morning only) and single half pannel shading from the apex of my neighbours house.
Total shading ruins output... 200-400watts Total
Total shading over half the panels is pretty much the same until only 1 or 2 panels are shaded when outout rockets from 300/400watta up to 2kw.
Recently with the low sun ive noticed the triangle shadow of the apex of me neighbours house on a single panel.
Curious of the output ive seen my sunsynk inverter display show fluctuations in current by as much as 1 or 1.5amps and then some rapid voltage adjustment when the sunlight is pretty consistent. I had a feeling the inverter was searching for a maximum power point... and I'm guessing this is due to the half cut panel characteristics...
I have ordered Tigo TS4s as this should help further mitigate some of the shading.
Your video explains exactly what I am seeing with shading and I understand why I see the shading effects in power output.
Thank you!
Hi, have you installed the tygo optimisers? Did you see any improvement?
I have a defective half cell 360W panel. First 1/3 of the left side in portait will melt snow faster and that particular panel output voltage is 2/3 of rated open circuit. There are 2 series of 8 identical panels with no partial shading. The power loss (120W from that panel + 120w from the unbalanced string) is not that concerning.
Is it the first bypass diode being shorted?
shingled is the new tech, better than half cut imo
What happens if we lay the panels on landscape setup ?
The half shaded single panel in a serial string will halve the current through the shaded bypass diodes but it will not increase the serial string voltage significantly. However, if it was two split panels in parallel, then the split panel shading would reduce losses significantly over a conventional panel.
So they would build them with 6 bypass diodes instead of 3, and two main buss bars. I suppose it would add a dollar or two at volume, but I question how many scenarios where you would see such complicated shading. Probably in residential installs with shading from dormers and trees. I live in a town that gets snow so it has steep roofs and lots of dormers, they would probably be beneficial here, by a few percent of total output.
I believe that the 3 bypass diodes are sufficient normally and solar panels are very cheap now after the price reductions of around 90% over the last 12 years so one can over power the array into the inverter and not worry about losing a few panels to shading when the sun is low and weakest
@@nicolasrenold
If the inverter performs its global MPPT sweep. Does that mean it will find the peak for the whole array? Will one panels being partialy shaded limit the current and even though the 2nd peak is better than with standard panels does that still mean every panel is still reduced to match? I.e If one panel in the array is partially shaded as shown at 6:26 reducing its maximum output to 180W I assume that still means that every panel in the array is reduced to 180W as well?
I am studying the layout for my 6 485w panels and my pitched roof is poorly oriented as it starts to get shadding diagonally at 6pm. If i instal the panels portrait oriented, they will start to shade the top left half, then the bottom left nearly at the same time the top middle half and so on. Is still portrait the best option here? I am glad I found this video as I was almost starting to install them in landscape orientation? They will get installed in sets of 2 for the best exposure.
I think microinverter is the best solution for your case. Every panel with a dedicated inverter to maximize power.
Before I viewed this presentation, I saw one from a guy who was attempting to make a point about how string inverters performed nearly was well as microinverters when panels were shaded. To make his point, he measured open circuit voltage, Voc, then short circuit current, Ish, for two cases, namely with a panel shaded and with all panels illuminated. Since Voc and Ish were similar for both the above cases, this guy then claimed that shading a panel in a string inverter system did not appreciably reduce power production.
Unfortunately, I suspect this analysis was WRONG because as your video demonstrates, the I-V curve of solar panels is HIGHLY NONLINEAR. The Voc and Ish can be converted to maximum power delivered ONLY if the system has a linear I-V curve.
Thanks again for clarifying this!
what about affect of shading on bificial ?
In properly orienting half-cut panels, does it matter which end is up in a portrait orientation? Or does proper orientation only mean portrait vs landscape -- and which end is up doesn't matter? I noticed that with my panels (all in portrait orientation), some have the serial number sticker at the top, and others at the bottom -- arbitrarily. (Some of my panels have the top half in shadow for a period of time, so want to make sure they're oriented properly.)
It doesn't matter whether the end with the serial number sticker is at the top or bottom, as long as the cables at the back are connected in the correct polarity.
This was my question as well as at 9:20 it refers to the bottom half of the panel
Gday folks, Can you tell me if Half-cut modules are ok to fit into an off-grid array. I am considering upgrading my old 185w panels with 390w panels.
Hi there! Yes, half-cut modules are installed just like any other solar modules. Please check out the relevant Australian Standards for any updates to your system.
I don't understand why the unshaded area gets half the current instead of the full current while the voltage is equivalent of the unshaded.
Are you wondering about why the string of 20 half-cut cells has the same voltage but half the current of a string of 20 standard cells? If so:
In a PV cell, the voltage is related to the band-gap energy of the material involved - in most PV modules this is silicon. There's no difference in the material when you cut the cell in half, so standard and half cut cells both have the same voltage.
In a PV cell, the current is related to the area of the cell. So when you cut the call in half, the current in the half-cut cell is half that of the standard cell.
I wonder if someone did real IV measureemtns. Everywhere I see only simulations and mind games. It looks like the only way is to do experiment myself..
My Hoymiles microinverter does not search for global maximum - it just cuts half at small shading. And gives 0 output at shading of 2 cells - one on each side of the panel at. Potentially it should have activated diode, but Hoymiles microinverter does not feel it..
Why you wrote bad information about shade on half cut panel ? One 60Ws section above shadding you forgot. 300W no 240W. You must study before explained !!! Ou ou....
Chainsaw
Lost credibility showing part shaded 60c as no voltage and current. That's not true.
I also don't think the examples are really a true account of shading in the real world.
I was wondering about the spilt panels.
I did notice that you didn't do any string examples. Because that 10a to 5 in a. String is a pull down.
Hi Rory,
Thank you for the comment.
We did make the decision to show shading as a complete lack of irradiation, to make the concepts easier to understand. In a practical situation, there might be 10-20% irradiation still available, due to diffuse sunlight, which in the video examples would correlate to a 0.5A-1A current per substring. Because this is very small compared to the full irradiation current, the operation of the MPPT and bypass diodes won't actually be affected; they will still operate as demonstrated in each of the examples shown. The only difference is that there will be a slight increase in power output when the bypass diodes are not operating (timestamps 6:27 and 7:49 may be up to 216W rather than 180W, and timestamp 8:55 may have up to 6A rather than 5A). Again, the operation of the bypass diodes will be unaffected.
For examples of shading effects in full strings, have a look at timestamp 8:01-9:00 - it's a similar effect to a single module but on a larger scale!
The 120 half cut solar module that you are showing does not have 120 cells. If you count, you'll notice.
Whoops!
@@GSES_Solar_Training What about the PERC Shingled technology used by HYUNDAI , can you compare with this?
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