If you are in DFW, don't hesitate to reach out: 972 675 7725 ( call or text) or shoot me an email: info@solartimeusa.com If you are not, you can also reach out, I do solar consultations and quotes review all the time :) Leave some thoughts below! I try to respond to all comments! :)
Great test, although I've seen so many conflicting tests on these! Two things I'd like to see done for additional testing would be: 1) Use another popular brand of string inverter (maybe Sol-Ark?). 2) Use more real-world realistic softer shading by placing something on front of the panels, but maybe 5'-10' away to allow some ambient light to still hit those shaded panels. Thanks again, you earned a new subscriber!
Best regards from france and Spain !! Our doubt is that the 2 series of panels are connected with a TIGO system (one optimizes and the other does not), but who says that the TS4-R-S does not influence the system without optimizing it? Have you tested panels connected directly with an inverter, without going through any Tigo device? If not, an ideal test would be a series of panels connected to a classic inverter and the other series to Optimizers. Of course, the details of each panel would not be available, but the general production of the whole would provide more than interesting data. Thank you for everything, you are great and your way of speaking English helps us a lot in Europe to understand your language more easily!!
How well do split panels do with this test? Looks like they have double the diodes and should be closer to using optimizers. Can you show us the costs for both systems? a 10% improvement with optimizers is probably not worth the 20% or whatever increase in cost.
Our doubt is that the 2 series of panels are connected with a TIGO system (one optimizes and the other does not), but who says that the TS4-R-S does not influence the system without optimizing it? Have you tested panels connected directly with an inverter, without going through any Tigo device? If not, an ideal test would be a series of panels connected to a classic inverter and the other series to Optimizers. Of course, the details of each panel would not be available, but the general production of the whole would provide more than interesting data. Thank you for everything, you are great and your way of speaking English helps us a lot in Europe to understand your language more easily!!
I think you are right, there is no possibility to have different amps through the system without optimizers. Difference in 0.05 amp could be just some measuring error, but 0 on one panel means no current flowing, so how the rest of panels is flowing? there is some kind of optimization in those "nonoptimizers". Simply decoupling PV panel from rest of the string still is optimization.
Of my 3 quotes currently, I have been offered a SunPower microinverter system, an Enphase with IQ7A micro's Jinko system and finally a Power Edge with optimizers system. Still trying to decide which system to accept. Your testing would indicate that I should look at a normal string system and wear the minimal loss of power. This begs the question that the industry is (in cahoots?) with the manufacturers to maximise the return for each installation by only offering micro or optimized systems. The price difference of each system varies from about $3000 in Australian dollars. I haven't even costed a string inverter system. Thank you for your efforts in "educating" us mere mortals in the intricacies that we are quite ignorant of.
The rapid shutdown requirement in the US requires an extra safety disconnect at the panels. It is easiest to meet this with microinverters or optimizers. Not sure if Australia is requiring this yet. It's unfortunate since I have seen many installs with microinverters fail. Even if they are covered by warranty, it is a pain to remove, reprogram, and then install again. Less electronics on the roof will be more reliable.
Thank you for sharing. Just so you know Sunpower microinverters are whitelabeled enphase microinverters...:) So essentially its the same product. Or at least it was when sunpower was offering microinverters here in the states. It wouldn't hurt to try to get a simple string inverter quote. It all comes down to shading, and if not much is present i really don't see the reason to pay extra for sth that would essentially be not useful. BUt if shading is heavily involved micros or optimizers are the way to go for sure. Ps. I plan to start testing shade effects on microinverters here pretty soon! :)
Hey! ShadeFix is automatically turned ON on most inverters so this included shade fix, but I do wnat to test two separate inverters one with ShadeFix on and Off to see what really it does. I almost cant imagine a drastic change, because the bypass diode worked, so I am very curious myself how DC would be then conditioned. Definitely need to TEST IT SOON! :)
It's great doing this, but I'm still left wondering whether the output of a string is severely affected by shaded panels. Of course the output of one panel is not affected by the one next to it, but in a serial string does a shaded panel cause resistance that reduces the string more than just the missing output of the shaded one? You should show the output of the string as well as the individual outputs.
Great video, I would love to see a video on panel efficiency and MNOT Power Output, and how often you are able to produce more then MNOT. On this video we see what I am assuming is a REC395aa-Pure panel producing a 323 watts, where the MNOT Power Output for said panel is 301w(7.2% above MNOT). I would love to see a video on what a panels peak is, and how long does a panel produces above MNOT on any given day. I have gotten around 8 to 10 qoutes, all using Enphase micro inverters, pretty much all of them are under-sizing them. Using an REC405aa-pure(MNOT is 309w) panel matched with an IQ8+ which only operates at 300w output, you are leaving a fair bit of power on the table due to clipping. Obviously it's almost entirely based on your specific environment, but I would love to see a video on MNOT Power Output and how often and how much you actually see above MNOT values.
That is such a GOOD idea! Yes! For sure want to test that. And like you said most will depend on the environmental conditions. If you’re interested I can send you some screenshots of what rec 410s generate during certain time of the year and some other ones!
In a truly series circuit, the current is the same through all the panels. The voltage of each panel can vary, adding up to the array voltage, divided by the entire circuit resistance (panels and load) ultimately determines the amperage, but if not enough amperage is available the voltage plummets to the point where V÷R=A becomes true again. So for any one panel to have a lower power with full sun than normal, would have to mean that it's being over loaded down to the point it can't maintain the voltage. When that happens VxA=lessW. This showed that did not happen in the series array here as the inverter adjusted its demand to match amperage availability. But theoretically the same thing could happen with a micro inverter on that one panel with full sun, using enough power to draw the panel voltage down thereby lowering its output wattage. Although I would think that the inverter would just cut off before that would happen, when it was the only panel with full sun it would be doing most of the work. But what I think actually happened here is all the inverters shared evenly, which meant it only drew from the panel with full sun an equal amount that it could get from the other panels so that each inverter was working the same and not overloading any one in particular. It doesn't mean the panel produced less, it means the inverter used less than the panel made available.
Modern panels are definitely so much better that optimisers are really questionable now. Being able to monitor individual panels and 10% are maybe worth it to some, but for me, I only have to worry about shading in the depth of winter, so 10% of a period that is not great (I'm in the UK), really doesn't bring enough to the table for the extra cost, but more importantly the extra complexity you are bringing to the roof. With the hot summers and cold winters, I want to keep it as simple as possible for the difficult to access roof and putting a bunch of extra electronics cabling and connections in an area that will see heat and cold for many years = a recipe for failures. But I can see why if you had easier access then it might be worth it.
@18:08 - that blew my mind! We are being lied to by installers big time. I have been designing a solar system for my home over the past two weeks, and have spoken with multiple solar system installer companies and without fail each one of them said that even if one panel is shaded in a string then it will impact all the remaining panels in that string. I am astounded after seeing your video!
THANK YOU. You should look into the PW3, its a hybrid inverter and it does not have any panel level devices.... bc we do not need them. I am not a huge Tesla Fan but they are truly making the future of solar super simple and I am so excited about it.
The discrepancy in the test results can be attributed to the fact that the devices under consideration measure the current leaving (and voltage) of the panel, rather than the current (and voltage) put on the string line. This is an important distinction, as the current on the string line is identical for all the panels, given that they are connected in series. In order to optimize the power output from the panel, it is necessary to reduce the current while increasing the voltage (or vice versa). This is achieved by approaching the maximum power point tracking (MPPT) operating point. However, in certain circumstances, it is not possible to increase or decrease the voltage sufficiently, resulting in a lack of optimal power generation for the specific shadowing condition. The shadowing of other panels affects the power produced by a panel due to the slow output current and the necessity for the optimizer to adapt its output current to the current of the string. This occurs while the optimizer attempts to counter the inverter's efforts to alter its apparent load in order to center the MPPT. It is crucial to note that an essential parameter was not measured: the voltage entering the inverter. When the voltage drops below a certain threshold, the inverter is unable to track the MPPT, leading to complete shutdown.
Excellent and thorough testing. I know this took much time to plan, execute, and report, so many thanks. Optimizers cost ~50% of panel cost, so the gain of 10% is hard to pencil out, though many other considerations like other installation costs and limited space for panels.
Hi Martyna, was the SMA shade fix switched off on the Tigo optimized panels, and was it switched on for the non-optimized panels? Towards the end of the video some production data is shown from the SMA monitoring platform but it is not explained which shade setup is being used for this production data
Again, this would be case specific. So what are the extra cost per panel if you include the optimizers ? If you have no more space on the roof..possible a true advantage if you calculate around 1.2KW/h per day in saved cost. But if you have enough space on the roof, what would be the result if you would have gone with a slightly larger system at parity cost?
In both of your videos about optimisers, we are not shown the total amperage of each array which is fundamental in order to, not only understand but also evaluate the effect of installed optimisers. Perhaps if you have that data and you could briefly share it with us, we would very much appreciate it. 🙏Thanks for sharing your tests.
This test actually shows the advantage (also for safety) of using a simple bypass diode in parallel with the solar cell groups. in order for the solar module to be efficient all the cells in a series circuit need to be producing the same voltage/amperage. If they are not the cells that are lacking become more resistive and produce heat. Heat is wasted energy and it can damage the non producing cell (even burn). Non producing cells in a string also start to have more characteristics that of an LED then a solar cell. If you could get the non producing cell from a string under load in a dark place you would actually see it give off some light as well. this reverse flow (biasing) is what causes loss in the string. it is also not good for the cell. A bypass diode gives another path for the electricity to flow. The theory is that the voltage will flow first through the path of least resistance. As the non producing cells heat up, they get more resistive and eventually the diode becomes the more prominent path. But, also bypass diodes create some voltage loss as well. Schottky diodes are used for bypass diodes in solar modules because they have higher series resistance then other type diodes and keep the reverse voltages at safer levels. Another use for diodes in a solar circuit is a blocking diode which blocks an entire module or string. Bypass diodes are installed in parallel, blocking diodes are installed in a series circuit. Thanks for all that you do!
Great video - thanks! Just to clarify, I assume the voltage and current measurements are made on the panel side of the optimizers and the monitoring electronics. On the inverter side of those devices, the current in each unit has to be the same since they are connected in series.
Exactly! The units measure the current on the input of the optimizers/ rapid shutdown device. Hence the current has different values. Its like seeing all panels in isolation.
Hi Martyna, how about shingled panels? Does there any reliable shingled panels that can perform better compred to half-cut with optimizer? How about the cost comparison with half-cut+optimizer and shingled panels?
Question: You refer to "Ever Since Bypass Diodes Became Used In Panels", since when was this? I cannot find this on the web. Your tests show that Panels with Bypass Diodes do not shut down the series string but what about older panels? I think it was is true with older panels, but how old is old?
i've seen demonstrations that showed that the optimizers don't work at all, and actually produce less power. It seems it is because of the 'blind deployment" without CCA+TAP. It's also related to a particular firmware from 2021, and not sure if that issue still exists. I'm very interested to know whether you tested "blind" or with CCA+TAP, and whether you found the TS4 to misbehave in any situations.
I don't undertstand: Are the panels in each string wired is series (in which case I expect then to all have the same current) or parallel (in which case I expect them to have the same voltage), or what?
Great video! Really helped me understand all this! This past summer I had a PV system installed on my house in San Antonio. It has 25 panels with mini-inverters and an Enphase system. The house does get significant shading from trees. I am already wanting to expand it. I do not have battery back-up but am considering installing it eventually. Also, the original installer (whom I shall never use again or recommend!) said there was no way to get power out of the system during a grid failure without a battery system, but as I understand it, there actually IS a device which allows for this. Do you know anything about that? Finally, the roof on my house is a low pitch standing seam metal roof. The current panels are installed on the south facing side. If I install panels on the north facing side would there be anything to gain by using a rack that will prop the panels up to an optimum south facing angle, especially if those are bifacial? (Roof is plain silver color) Thanks again for your great, informative videos!
You need to "island" your system if you want it to work while the grid is down, the inverter needs the grid frequency to have power so you will have to have something to provide this. Other than a battery system I don't know whats available in the US to do this. Im in Australia and have sold solar since 2011 but inverters/ micro inverters work the same anywhere so thats the issue you face
Hi! I am so sorry for the delay in responding to you. So yes, there is an option to use power during the grid outage with enphase. I will include the link enphase.com/homeowners/sunlight-backup-user-guide?hsa_acc=1236416428&hsa_cam=20130257651&hsa_grp=&hsa_ad=&hsa_src=x&hsa_tgt=&hsa_kw=&hsa_mt=&hsa_net=google&hsa_ver=3&gad=1&gclid=CjwKCAjws9ipBhB1EiwAccEi1Ld_T4TDI6NVlLA4375BrzzSQ9S33Y1lcXp6b6okeMKnX7FlpZXgCBoCvmIQAvD_BwE The downside is it’s like having a battery set up ( cost of extra equipment) but no battery. I don’t think it’s worth the cost. It might cost over 4K maybe even close to 6k if there is a need for rewire. I suggest waiting till you get a battery becasue you will spend money once and have a good back up solution. As far as pitching panels, you can email me and I can check the roof and see if that would make sense. The struggle here is that when you pitch panels you have to have spacing between them since they will start shading one another so you’re limiting space, and by just installing them facing north might cost similar to just have more panels, than less but a pitch. Email me if you want me to review the address :) happy to help, again so sorry for my delayed response. Info@solartimeusa.com
On DIYSolar forum, a person was getting a whole string shutdown in a different shade environment. No optimizers on the string. After a lot of testing it appears like the bypass diodes were not working. Doing tests like yours, they did work. Although I absolutely applaud you trying to do objective tests, those of us with statistics background know about “lurking variables”. In this case, those lurking variables we know would be different panels, different bypass diodes, different shade profiles, etc. (but there are many other variables we don’t know about”.) Trees and filtered light will NOT work in the same way as your “leaf” and cardboard tests. Still, there was some learning here. May want to simulate real life partial shading on the next test.
Tigo optimizers cost me $22/panel on a 44 panel system and produce a 6.4% improvement in generation for 1.5% increase in total system cost. ROI in the Tigo optimizers is 4.4 years while it's closer to 13 on the whole system.
Additionally, sometimes adding 6% extra panels is not just a roof space issue but a string configuration issue, ie. You can't just add another panel to a 2x12 string.
Can you do it again with half-cut panels? Ideally once vertically and once horizontally mounted with a flagpole shadow and a wide diffuse tree shadow sweeping across a full module? I suspect half cut modules are better mounted horizontally so a horizontally moving thin shadow only shuts down half a panel at most. But a tree shadow would be way more interesting.
Hey this is amazing! I’m really struggling to pick between a local installer and Tesla here in upstate New York. For a same sized system Tesla is estimating. 6300kWh / year but the local installer is estimating 9478kWh/ year. Whose right! I even did a shading analysis in helioscope and the local installer was much closer it seems. Why is Tesla estimate so low? Is it cause of their string inverter vs local installers micros? Thanks!
Hey! I would say go local, if the company has good reputation, good online reviews and if they have been around for some time. Does the installer offer any production warranty? Tesla is undershooting so they don’t have to deal with complaints if underproduction later on. So they are playing safe. The biggest problem I see with Tesla is service. In DFW in texas I service Tesla systems weekly at a charge becasue of how long they wait for service from Tesla. So if you can choose an installer that will service your system in the future, that’s the way to go. Local company might have a more expensive price but you’re also supporting local over huge corpo where nobody cares about you. I am biased because I am a local business too. But I think you will be better off going local if company is reputable. I hope this helps 🙌🏼
The panels were connected in two separate strings and in two separate inverters. Does that answer the question? That should not cause any changes in the tests as they were connected in an identical way.
This is really an amazing video. Thank you for actually performing tests and sharing real data. Regarding tests 10, 11 and 12 where the non optimized panels were higher on individual panels, I think this is not important and that the optimized panels are working together to produce overall more wattage with the same shade. Looking at just the shaded panels (wattage), Test 10: Optimizers 24+173+171=368 vs non-optimizers 0+195+100=295. Test 11 optimizers 170+191+191=552 vs non-optimizers 0+188+216=404, and Test 12 optimizers 174+196+194+193+193+173+193=1316 vs non-optimizers 0+213+201+198+213+0+105=930. For example, on test 10, 173+171=344 Watts vs 195+100=295 watts. You end up with more overall wattage because the 2 optimized panels matched each other even though looking at just one panel, 195>173.
If you are using a string inveter with all 8 panels in 1 string, how is it possible for shaded panels to have less current than the full-sun panels? My system is strings of 6 panels, and I thought optimizers were required to prevent a shaded panel from reducing the output of the other 5 panels in the string?
SO the way the optimizers work is the try to find ( in mathematical term) best PRODUCT of the two (voltage and current). Sometimes they have to lower the current to increase the overall production outcome. Also the optimizers do provide the INPUT values, so whatever enters ine optimizer, not the outcome. So later on the string MPPT also equalizes the values to track the bets power point of production. I hope that made sense? Martyna
At roughly $100 per panel to install Power Optimiser, works out to $1000 for a string of 10 panels, for that same $1000 you could purchase 5 more panels at roughly $200 per panel, giving you a string of 15, the output then would blitz the output of the 10 power optimised string, subject of course if you have the room for 5 extra panels.
Cześć, bardzo dobrze widać że dodanie Tigo tylko w wersji monitoringu do panela HalfCut zupełnie zmienia jego działanie. Diody bajpasowe nie powinny zadziałać po zasłonięciu połowy panela tylko prąd modułu powinien spaść o połowę - niestety w takim przypadku prąd całego stringu też by spadł o połowę więc dodanie Tigo bez optymalizacji to właściwie poprawia działanie całego tego systemu bo załącza się w nim wbudowana opcja bajpasu. Moduły HC sprawdzają się tylko z mikroinwerterami lub optymalizatorami. Co da samego testu zacienienia to w przyszłości proszę postawić przed panelami cienką rurkę lub powiesić linkę symulującą przewody zasilania lub cienkie gałązki. Taki "soft shadow" ma druzgocący wpływ na pracę całego całego układu stringowego - cień jest na tyle mały że diody bajpasowe się nie aktywują, a spadek prądu całego stringu jest ogromny. W takich przypadkach widać dopiero zyski z optymalizacji.
Another very good informative video. Given the increased costs with MI/Optimizers and the extra components required for panel level monitoring and combiner boxes, which typically have only a 5 year warranty, would money be better spent on a couple more panels. I know, it depends... hahaha Curious about filtered shading such as tree branch or power line 20 ft away.
Yes! I definitely want to apply that sort of shading. And test with cloudy days etc. if you look at tests 6-9 they have the building shadow applied and both sides were pulling out same power outputs! Little sneak peak into future video with filtered shading!!! 🙏
Compared to a rapid shutdown system, the cost for the optimizers is marginal ($10/panel + $500 for the controller/monitor). Tigo optimizers also carry 25 year warranty, not 5. Mine work exceptionally with a chimney on the south side and a 2nd story dormer and some trees on the west side.
@@greg_takacs Yes, more components required for Tigo which increases costs. And Tigo components such as Cloud Connect are only 5 year warranty. Same as Enphase Envoy and combiner box, 5 year. And if using SMA inverter, SMA makes it clear they do not support other manufacturers products. Not saying Tigo is bad. Its obvious that most customers have no idea what they are buying and are unable to make a full comparison.
Greetings, I am currently residing in the state of Florida and employed in the field of construction. I am interested in exploring the possibility of collaborating on the construction project you mentioned. Would it be possible for us to have a discussion regarding this matter? I am currently exploring the option of replacing our electrical service with a battery power bank for our job site trailer.
Hey! I used the Tigo Rapid shutdown devices, that offer monitoring and rapid shutdown feature, with supposedly no optimization :) Her is the link: www.tigoenergy.com/product/ts4-a-s
I'm not sure what that per-panel monitoring box is doing, but it is not behaving as series string of panels without those boxes. Interesting test none the less, but I don't think it will apply to a string without electronics at each panel.
Hey! Thank you for your comment. The units are called tigo Shut down devices. Supposedly they do not “condition” the power simply provide rapid shutdown and monitoring ( reading data) feature. But! I do want to test them compared to simple string inverter to test whether a string behaves like that or not. I am curious myself. Thanks again for leaving your thoughts! I appreciate it
The problem originally came from solar panels that do not have bypass diodes. So a leaf on a single panel would drop production on the whole string by that %. So the 20..30% drop would be for all panels due to the single leaf on a single panel. The bypass diodes prevent this as you have clearly demonstrated. Thanks! I do have 8 of these pre bypass diode panels, but they won't see leafs or antennas (230Wp), but my next panels might get shaded, but have bypass and are slightly more than 500Wp. And there will be about 40 of them instead of, because I hope that would cover my winter days instead of having to settle for a bio-diesel generator. (a 500Wp solar panel is around $125 these days, a bio diesel is about $1500 so in costs I can have 6 panels with 2 mppt's)
yes, exactly! Yet the industry keeps using that to sell their own products. Just want people to have proper facts! :) I actually want to test older panels too, we have some leftovers in the warehouse from 2015s and prior... could be a fun battle to see :D
Great work !!! Best regards from Spain. As you said, the first real test I found in internet. In Spain 80% of the people use Hibrid Inverters, and in France 70% use Microinverters... Why ? No idea.. If you don't mine , I will post your videos on European forums. Best regards
Was SMA Shadefix from the inverter used in these tests? Next test to try is SMA vs a few different inverters (GoodWe, fronius, Sungrow) under the same conditions against eachother.
I would also be very interested in the answer to this question: Was SMA Shadefix from the inverter used in these tests? I would expect other results that make the optimizers look questionable.
ShadeFix is automatically turned on for all SMA inverters and YES I do really wnat to test two different settings, with and without shade fix and see how much effect it really has. But seeing these results I wonder how different it would be since bypass diodes would work before the power gets to the inverter. DEFINITELY WANT TO TEST THEIR THEORY! :)
Have I missed something, but I am not clear if these are 8s or 8p strings. I think I would always string at high volts but with 8 panels you have 4s2p and 2s4p configurations to test, at least on the non inverter side Also you should repeat the experiment on a day when sun is not 100%...winter sun is so useful in off grid use cases.
@@solartimeusa, are you sure that the SMA Shadefix was active? Fronius for example claim, that their shadow management is even better than optimizers.
I think it will depend on the situation. I for example have east and west-facing roof, and I absolutely do not need them, but for the low cost of like 25-30$ you can get the rapid shutdown ones with the monitoring capability, so its a relatively low cost and I get to show off the monitoring. But for the optimization, I really do not need it, as no trees surround my home and the strings are divided.
I bet, if you compare "with optimizers" array with "no optimizers or bypass diodes" array - results would be so much different. Since the bypass diode actually does its job as well, and it optimizes the power output of a whole string/array based on the switching off capabilities it has.
Please explain why the currents for the panels in the string without power optimizers are different, more or less, from each other even when completely un-shaded. Since the panels are all in series, each panel must generate the SAME current.
Hey Bob, great question. Tigo units measure the current on the input of the optimizer, not at the output. So coming into the optimizer, the input current is smaller, based on the panel itself, then the units do their job on the optimizer side. And on the side with the rapid shutdown devices the current passes through and is also equalized to the string current. So the monitoring is reading what is happening at the panel level not past the optimizer. Does that make sense?
Fantastic. Thanks a lot! I just got my 18 panel installed with the tigos. Pretty sure there is not an actual ROI under my conditions. But the generated data and graphics are so cool :-)
It would be interesting to do the shade-from-building testing with the panels in landscape mode. Most panels strip the regions along the long length of the panel for each area covered by a bypass diode. That means the panels will work better in horizontal placement as the sun goes up or down. (I don't know if the optimizers would make a difference though)
They did do that test, it's towards the middle of the video. Additionally you can read this thread with a lot of good info from me and my system regarding all kinds of shading my system experiences diysolarforum.com/threads/can-shading-be-dealt-with-by-parallel-strings.54317/
That is a very good point, I do wonder the same. Surprisingly panels that were shaded in half and didnt have optimizers, completely shut down, which makes the marketing for half cut cell panels BS? I really want to test that too.
Hey David. This is a good point, but the percentages can be complicated, as easy as it sounds. The final percentage results from deciding which number is the starting number and new number. For example if we are trying to calculate the increase from 87 watts to 157 watts. Original Number is 87 New Number is 157 Formula The increase -> 157-87 = 70 (70/87)x 100 = 80 % But if we try to calculate decrease from 157 to 87 numbers change, and that is what I used. Now if we flip it, and now the original number is 157 New Number is 87 Formula the Increase - 70 (70/157) x 100 = 45% The question becomes which one is our point of reference... :)
@@solartimeusa It's not at all complicated. The question as to the point of reference was decided as soon as you referenced the "increase" in power. If a value was 100 and then became 150, the increase is 50% ... not 33%. It is not questionable.
Hi Martyna, or Martina? ;-) Nice video!! I only little bit don't what all these boxes are. You showed two smaller black boxes with some cables... Does it mean that each solar panel has one black box connected underneath (so there are 16 hidden boxes)? It would be nice to see wiring from back of panels. And you are speaking about diods - are they in those black boxes or are they built-in solar panels? It would be nice to see some theory first (for such beginners like me) - like wiring diagram of both configurations. (If black boxes are placed in both strings, then it would be nice to have third string without any black boxes - 5 panels in each string is enough, no need for 8.) And I'd love to see what each black box actually do. Now I maybe understand that first black box if only for measuring current and voltage but is passive - doesn't do anything. (if so, then 3 strings doesn't make any sense) And second with optimizer is basically acting like tranzistor which is connected in parallel to panel and if there is shadow (power drop down + increasing internal resistence of solar panel), it opens itself partially and allows bypassing current from other panels from the string? (Btw excellent clear English, I am CZ and can't hear almost any accent.)
Hey! Its Martyna ( Polish) but when pronouncing it in english it is pronounced like Martina. Yes so each panel has a small back box behind, that is built in, and it includes the bypass diodes. Then what I did is used 8 power optimizers ( extra black boxes) under one set of panels, and 8 Rapid shutdown devices ( extra black box) under the other eight. I would love to dig deeper into how they are wired, hopefully in the future video. But in an easyway speaking the panels have their connectors that connect to power optimizers ( male and female connectors) and then those then connect in series to other panels. There are two ways of connecting panels together either in series or in parallel. I definitely want to do a video on that, so make sure to subscribe :)! Thank you for leaving the comment!
Oh wow! You know you can email me directly and I can try to help you determine which one is most realistic! I do consulting for homeowners outside of my work area :) Info@solartimeusa.com
Not so concerned about individual panel knock downs, but total power output of whole string. I would like to see this repeated with two strings in parallel like Tesla Solar Loves to do. I would like to see how different azimuths and pitch’s affect daily production on a single string.
Can you actually know which panel is underperforming without monitoring hardware... Because if i have to pay for the monitoring hardware you used then i might as well get optimisers
Yes and no. If you have a string inverter with no optimizers or no monitoring devices, then you can see drops in particular sting's voltage at the inverter screen. So you can identify the string ( group of panels) that might have an issue. The problem is that panels DO NOT FAIL. They don't have moving parts or sophisticated electronics. Usually is the microinverter or optimizer that fails... so you have it there to see which one fails. Its almost funny as I write it. I feel like its the marketing of panel level monitoring is what made us think if you have a panel level device, then you know when the panel fails, well they dont ... :D at least not very often.
@@solartimeusa thank you so much for your response.... It wasn't really about failure... More so that I could identify where I have an issue with shading or whatever(I'm sure I'd spot a leaf😁) your videos have been very helpful and informative... I plan to buy a home next year so I'm trying to find out as much as I can. I was leaning towards not using microinverters or optimisers after watching your video... My only concern was monitoring but if it's not a big deal I'd rather not spend what I don't need to
That is a very good question!!! And the problem is the answer is not super straightforward. This will definitely depend on the severity of shading. In some cases shading is so minimal that it wouldn't be worth it, sometimes space is limited so power optimizers are the better option.
Very impressive test! Constructive criticism: if testing partially shaded panels, it would be far more reliable and scientifically correct to use a jig to accurately position the leaves so they cover exactly the same amount of the same cells in each panel. It may or may not affect the results, but at least you’ve eliminated a variable. Keep up the good work!
@@solartimeusa making tape “loops” and keeping the tape completely behind the obstruction would also be a good idea. Thanks for the reply, it’s great to see creators who engage with the comments! 👍
Thank you for this test. I recently watched another video suggesting far less of an impact on string shading, but their test method, presentation, and conclusions were already suspect to me.
Thank you! I plan on doing other tests with similar shading but also with different brand inverters. I also want to test more filtered shading like trees. :) I am curious if results will be similar or very different.
Interesting stuff. You're right, the repeated narrative over and over has been, shade one panel on a string and the rest only produce the amount of the shaded panel. Obviously, this isn't necessarily the case. Do the brand of panel and maybe age of panels make this hypothesis different? I would like to see a test of two systems with mixed panel wattages and see what that does on a string system. That's another thing that is always repeated as a no-no, never mix wattages. How would that look in this same test?
Thanks for the feedback, and yes that would be a really cool test, to mix brands and panel voltages. Like adding a 480W panel to a 400 w panel string! Thanks for the idea!!! :)
Another benefit of optimizers is the ability to mix different panels within a string (within reason). Note that the Tigo optimizers are buck converters not buck/boost converters therefore they can only turn higher voltage lower current into lower voltage and higher current, not the other way around. This generally is fine unless you're starting to look at and work with uneven size parallel strings going to the same inverter input and the likes ;-).
I think the real test is to run them side by side for an extended period of time. Don’t forget that modules and components within the modules will deteriorate over time - this will have a huge impact on performance as time passes by. Not to mention cloud cover and soiling which are inevitable. The inverter’s role really starts to pay off not on day one but over the 15 to 20 year life span of the system. Nearly every test I’ve seen on the subject does not cover the subject of long term yield
Thanks! I can explain the worries about "one shaded panel affects the others". You can see the data with your own tests, but the measuring devices/timing are very imprecise, so it wasn't obvious. When batteries/panels are connected in series (string) and you put a load, _exactly_ the same current passes through all batteries. No exceptions. The power-meters here you can see are not good, reporting 7.93A on one panel but 7.99A on another and 8.05 on another. That is physically impossible. It's possible that they are precise but the measurement+reporting happened a few milliseconds apart in time instead of simultaneously. Anyway, when one panel can do only 3.99A 36V due to shading, you can't possibly get more or less current than 3.99A from any other panel. So that's why people are worried that suddenly the whole string would produce half the amps thus half the wattage. Instead, the MPPT tries to draw different amount of input current, to find the sweet-spot. It tries 8.01A, the voltage of the shaded section rapidly falls below 0.6V as it can't meet demand, its diode turns on and the remaining 2 sections of a panel now output 8.01A 24V together. All panels resume to run at 8.01A, and the total voltage is simply 12V less. So, with 10 panels you don't lose half the total wattage (getting 3.99 x 36 x 10 = 1436.4W instead of 2883.6W). You only lose 12x8.01 = 96.12W, you get 360-12=348V 8.01A instead of the full 360V 8.01A. You see this in all your tests: all panels produce around 7-8A, and some of the sections of panels get turned-off, producing 0V and 7-8A. Well actually each diode that turned-on eats 0.6V * 8 = 4.8W and turns it into heat. The reported voltages on fully-shaded panels seem incorrect. It shouldn't be 40V 0A but 0V 8A. Actually -1.8V 8A. It must be a software bug. The bypass diodes ensure that suboptimal sections of the panels are turned off. The MPPT does a good job of finding the optimal current to use from the remaining turned-on sections. The resulting voltage of each section depends on that current (e.g 9V at 8.6A or 12V at 8.01A). Solar panels come with optimizers built-in: those bypass diodes 😤. A future improvement would be: remove the bypass diodes, and connect a new kind of optimizer with 4 wires to the panel. Optimize each section independently. I don't see it happening any time, soon, though. Currently the optimizers get crippled by the bypass diodes.
Hey!!! Thank you so much for the thoughts and input! I should have explained in the video that the Tigo units dont measure the OUTPUT of the optimizers/rapid shutdown units. It is measuring the input from the panel itself, so we can see them all separately in isolation. So the actual current of the string is the equalized by the mmpt in the string inverter itself, so I can totally see how that seemed misleading. What I learned from Tigo ( as much as they could tell me) is the units measure the input not the output of the unit itself. But this LEADS me to ANOTHER TEST! Lets see if I put 8 panels with the TS4S ( no optimization) and just string inverter with no units under the panels, and compare the outcomes. I am very curious how the results will vary, and if they will. I do like your idea too!!! Hopefully one day! :) Martyna
@@solartimeusa You may be interested to learn that Tigo record both Vin and Vout for each panel, but for some reason Vout isn't made available directly in their charting application. Good news is that you can just edit the URL, adding '&suffixes[]=vout'. The data is also available via their API.
panels have an efficiency, an amount they can generate for a given amount of sun. cover half a panel, IE give it half as much sun, you will get half as much production, no magic box you can buy to add onto a panel will or can change that. top say that covering half a panel and yet still get 3/4s the power, means your changing the efficency, and thats not really possible. when panels are in series then 'per panel bypass diodes' are the only option available to you, per cell bypass diodes cant be added after the panel is built. best cure for localised shading, micro-inverters to ac or individual mppt->dc->boost to a dc bus
nice videos. I would have made sense to spend a minute at the beginning showing the sub-strings layout on these panels, if they are half-cut cells and explain how many bypass diodes they have.
I really want to test fronius ability to optimize string, a few people asked about it too! That would be a very good test! I am definitely starting lots of tests this month! :)
It makes no sense that some of the currents on the "no optimizers" panels at 3:32 are different from each other. The high is 7.23 Amps while the low is 6.97 amps. They should all be the same because all the panels are electrically in series.
Hey Bob! You are very correct, the power optimizer and the shutdown units, are measuring the input not the panel, then the current is equalized on the string mppt level. Hope that explains that. :) Thanks for sharing your thoughts and concerns.
@@solartimeusa I'm sorry but you don't understand the basics of electronics. The current readings from the "shutdown units" should all be EXACTLY the same. Good luck to you.....
@@bobhilder1469 Bob I just realized in my message I had a typo above, I said “not the panel” what I meant “ off the panel”. Shutdown units are measuring current OFF THE PANEL at the input level of the device, not the output of the device. Not the current of the string as a whole.
Also the measurements are done in the unknown way, when I asked tigo how it’s done they couldn’t explain it without breach of their proprietary technology. And this is the way they also explain it to me, same as I did to you.
I only have shading in AM/PM when sun moves into field of panels or out of field. My neighbor has string inverters with optimizers which cost more than I paid for each panel. I bought used. Adding more panels and another inverter for me or anyone with no shading is the way to go if they also have a all in one inverter like I do which is 2 5k inverters.
Thank you for sharing! Yes unless there is substantial shading I would not worry too much about the optimization whatsoever! Thank you for leaving a comment.
I really think spending your $ on more photovoltaic surface are has a better ROI than spending $$ on extra subsystems like optimizers. A optimizer costs near the same as a 2nd panel for only a 10% gain, where 2 panels is a 100% gain for the same cost?
Thank you so much for the kind words. I so appreciate it. I am just starting my youtube venture, so I hope in the future youtube algorithm will pick things up more! :)
The tests show that your money is better invested in more solar panels than optimizers. The panels will likely last for decades while anything electronic is looking for an opportunity to fail. Of course,ground mount is better regardless of optimizers or not because of ease of maintenance.
Very very fair point, lots of people feel same way, the only issue in usa is the rapid shutdown law.. that makes us use some sort of panel level device for rapid shutdown ; /
Yes definitely. I do see big benefit in them, just for the most cost effective solution, sometimes not needed. Thanks for sharing your thoughts, I appreciate the comment! :)
It looks that, when more than 70% or 80% of the panels are covered by shadows in a string, the optimisers just try to work at a medium level of current and voltage for all the serie.
So now that you've dispelled the perception that micro inverters do not have a big advantage what other advantages are there for string inverters? I'm planning on installing a solar system but keep flip flopping back and forth between the different type of systems.
I think the benefit is not with a string inverter but with a hybrid inverter, one that can handle DC coupled batteries and whole house loads without the need of a critical load panel. These are obviously larger and more expensive that throwing a handful of panels with micro inverters on the roof but they provide far more utility and lower overall cost when you factor everything in. Adding batteries to a micro inverter setup is buying the inverters for the batteries all over again.
That's a good idea to test thin film panels! I do see their applications on camping and RV trips, not as much for residential homes, but definitely want to test their ABILITIES! :)
one thing is missing to me... The test was o so great... what about to take the same money what optimizers costs and buy more panels without them and try that comparison (what do you get for your money).
Yes very good point! I’m actually testing other equipment like microinverters now. But definitely want to test different shading type like filtered shading from trees etc. stay tuned ! And thanks so much for leaving a comment! It helps me so much!
You have just answer my question that I posted in another video of yours regarding the need of optimizers in set up with no shading issues. I guess that uneven panel degradation over time and / or dirt accumulation on the panels play no practical role on the question optimizers or no optimizers. That is, because we are talking long term. Regarding the existence of the Tygo panel level emergency shut down modules on the no optimizer side of the test panels, these modules are just switches, hence their cheaper prices. Tygo introduced this solution in order to serve consumers who have some Code to abide to but not necessarily have shading or monitoring concerns. Being , nothing more than switches, they introduce extra resistance in the circuit as opposed to a straight wire connection. Therefore, your test results are 110% valid and actually on the conservative side as far the performance of the no optimization panel side. If you remove these switches completely on that side, the panel output will be slightly higher than with the cutout switches on.
I am so sorry I missed your other comment. I really try to respond to them all! :( But thank you so much for leaving your questions and feedback and thoughts, it helps me a ton, and obviously, I love to know if I make any mistakes while we test those different products, so I can improve and keep learning.
What a great video, thank you very much for the transparency and honesty, The way you explained it was so easy to understand. Looking forward to watch your next vids.
Where space is not constrained you can probably install extra solar panels with the money saved from not using micro inverters. This is especially relevant for ground mount systems.
Togo optimizers don’t have a buck or boost circuit between the mppt and the string. So on Test twelve, fifth panel, the current is being limited on the first panel to the same as the others on the string. All current on a string has to be EQUAL on the string. I really want to see this test repeated with a string of enphase inverters.
If you are in DFW, don't hesitate to reach out: 972 675 7725 ( call or text) or shoot me an email: info@solartimeusa.com
If you are not, you can also reach out, I do solar consultations and quotes review all the time :)
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Great test, although I've seen so many conflicting tests on these! Two things I'd like to see done for additional testing would be: 1) Use another popular brand of string inverter (maybe Sol-Ark?). 2) Use more real-world realistic softer shading by placing something on front of the panels, but maybe 5'-10' away to allow some ambient light to still hit those shaded panels.
Thanks again, you earned a new subscriber!
Yes! I definitely plan on testing many different products and with more filtered shading as well! Thank you so much for subscribing 🙏
Best test IV seen yet! Great video. Really cleared things up for me.
Best regards from france and Spain !! Our doubt is that the 2 series of panels are connected with a TIGO system (one optimizes and the other does not), but who says that the TS4-R-S does not influence the system without optimizing it? Have you tested panels connected directly with an inverter, without going through any Tigo device? If not, an ideal test would be a series of panels connected to a classic inverter and the other series to Optimizers. Of course, the details of each panel would not be available, but the general production of the whole would provide more than interesting data. Thank you for everything, you are great and your way of speaking English helps us a lot in Europe to understand your language more easily!!
What should we test next!?
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Diffused shading from trees that moves across the panel array would be neat to see
@@notexpected ....yes, do this !!!
How well do split panels do with this test? Looks like they have double the diodes and should be closer to using optimizers.
Can you show us the costs for both systems? a 10% improvement with optimizers is probably not worth the 20% or whatever increase in cost.
BougeRV solar pales.
The voltage should be 0 or negative when the bypass diodes conduct...
Or does the tigo disconnect it from the string?
Good question, but I agree.
Our doubt is that the 2 series of panels are connected with a TIGO system (one optimizes and the other does not), but who says that the TS4-R-S does not influence the system without optimizing it? Have you tested panels connected directly with an inverter, without going through any Tigo device? If not, an ideal test would be a series of panels connected to a classic inverter and the other series to Optimizers. Of course, the details of each panel would not be available, but the general production of the whole would provide more than interesting data. Thank you for everything, you are great and your way of speaking English helps us a lot in Europe to understand your language more easily!!
I think you are right, there is no possibility to have different amps through the system without optimizers. Difference in 0.05 amp could be just some measuring error, but 0 on one panel means no current flowing, so how the rest of panels is flowing? there is some kind of optimization in those "nonoptimizers". Simply decoupling PV panel from rest of the string still is optimization.
Of my 3 quotes currently, I have been offered a SunPower microinverter system, an Enphase with IQ7A micro's Jinko system and finally a Power Edge with optimizers system. Still trying to decide which system to accept. Your testing would indicate that I should look at a normal string system and wear the minimal loss of power. This begs the question that the industry is
(in cahoots?) with the manufacturers to maximise the return for each installation by only offering micro or optimized systems. The price difference of each system varies from about
$3000 in Australian dollars. I haven't even costed a string inverter system. Thank you for your efforts in "educating" us mere mortals in the intricacies that we are quite ignorant of.
The rapid shutdown requirement in the US requires an extra safety disconnect at the panels. It is easiest to meet this with microinverters or optimizers. Not sure if Australia is requiring this yet. It's unfortunate since I have seen many installs with microinverters fail. Even if they are covered by warranty, it is a pain to remove, reprogram, and then install again. Less electronics on the roof will be more reliable.
Keen to know which you decide and why
Thank you for sharing. Just so you know Sunpower microinverters are whitelabeled enphase microinverters...:) So essentially its the same product. Or at least it was when sunpower was offering microinverters here in the states.
It wouldn't hurt to try to get a simple string inverter quote. It all comes down to shading, and if not much is present i really don't see the reason to pay extra for sth that would essentially be not useful. BUt if shading is heavily involved micros or optimizers are the way to go for sure.
Ps. I plan to start testing shade effects on microinverters here pretty soon! :)
Was SMA Shadefix turned on with this test? Have you tested to see if production is better with Tigo Optimizers and Shadefix or just Tigo Optimizers?
Hey! ShadeFix is automatically turned ON on most inverters so this included shade fix, but I do wnat to test two separate inverters one with ShadeFix on and Off to see what really it does. I almost cant imagine a drastic change, because the bypass diode worked, so I am very curious myself how DC would be then conditioned. Definitely need to TEST IT SOON! :)
Probably the best test example on YT using latest up to date premium components.
Thank you so much for saying that :)!!!
It's great doing this, but I'm still left wondering whether the output of a string is severely affected by shaded panels.
Of course the output of one panel is not affected by the one next to it, but in a serial string does a shaded panel cause resistance that reduces the string more than just the missing output of the shaded one? You should show the output of the string as well as the individual outputs.
How about showing something more common such as a cloudy day or a overcast day. This would be interesting as well.
And filtered shading such as tree branch(s) or utility line 20 ft away...
YES! Great idea. These were definitely super extreme conditions. Curious to test that! :) Thanks for leaving the idea!
YES! I really want to test that next! These were super extreme conditions... :D
Cloud or overcast has no impact as those are global sharing and impact every panel the same. Percentages will remain the same.
@@greg_takacs This was my assumption based on their 6-9 test where te building partly shaded the panels.
Great video, I would love to see a video on panel efficiency and MNOT Power Output, and how often you are able to produce more then MNOT. On this video we see what I am assuming is a REC395aa-Pure panel producing a 323 watts, where the MNOT Power Output for said panel is 301w(7.2% above MNOT). I would love to see a video on what a panels peak is, and how long does a panel produces above MNOT on any given day. I have gotten around 8 to 10 qoutes, all using Enphase micro inverters, pretty much all of them are under-sizing them. Using an REC405aa-pure(MNOT is 309w) panel matched with an IQ8+ which only operates at 300w output, you are leaving a fair bit of power on the table due to clipping. Obviously it's almost entirely based on your specific environment, but I would love to see a video on MNOT Power Output and how often and how much you actually see above MNOT values.
That is such a GOOD idea! Yes! For sure want to test that. And like you said most will depend on the environmental conditions. If you’re interested I can send you some screenshots of what rec 410s generate during certain time of the year and some other ones!
@@solartimeusa Yeah if you could that would be amazing.
awesome test. HUGE-HUGE Thanks!
Thank you so much for taking the time to leave a comment, and share your thoughts.
In a truly series circuit, the current is the same through all the panels. The voltage of each panel can vary, adding up to the array voltage, divided by the entire circuit resistance (panels and load) ultimately determines the amperage, but if not enough amperage is available the voltage plummets to the point where V÷R=A becomes true again. So for any one panel to have a lower power with full sun than normal, would have to mean that it's being over loaded down to the point it can't maintain the voltage. When that happens VxA=lessW. This showed that did not happen in the series array here as the inverter adjusted its demand to match amperage availability. But theoretically the same thing could happen with a micro inverter on that one panel with full sun, using enough power to draw the panel voltage down thereby lowering its output wattage. Although I would think that the inverter would just cut off before that would happen, when it was the only panel with full sun it would be doing most of the work. But what I think actually happened here is all the inverters shared evenly, which meant it only drew from the panel with full sun an equal amount that it could get from the other panels so that each inverter was working the same and not overloading any one in particular. It doesn't mean the panel produced less, it means the inverter used less than the panel made available.
Modern panels are definitely so much better that optimisers are really questionable now. Being able to monitor individual panels and 10% are maybe worth it to some, but for me, I only have to worry about shading in the depth of winter, so 10% of a period that is not great (I'm in the UK), really doesn't bring enough to the table for the extra cost, but more importantly the extra complexity you are bringing to the roof. With the hot summers and cold winters, I want to keep it as simple as possible for the difficult to access roof and putting a bunch of extra electronics cabling and connections in an area that will see heat and cold for many years = a recipe for failures. But I can see why if you had easier access then it might be worth it.
@18:08 - that blew my mind! We are being lied to by installers big time. I have been designing a solar system for my home over the past two weeks, and have spoken with multiple solar system installer companies and without fail each one of them said that even if one panel is shaded in a string then it will impact all the remaining panels in that string. I am astounded after seeing your video!
THANK YOU.
You should look into the PW3, its a hybrid inverter and it does not have any panel level devices.... bc we do not need them. I am not a huge Tesla Fan but they are truly making the future of solar super simple and I am so excited about it.
Would be awesome to see the same test with Solar Edge. Also would be nice to see performance of various/popular string inverters
The discrepancy in the test results can be attributed to the fact that the devices under consideration measure the current leaving (and voltage) of the panel, rather than the current (and voltage) put on the string line. This is an important distinction, as the current on the string line is identical for all the panels, given that they are connected in series.
In order to optimize the power output from the panel, it is necessary to reduce the current while increasing the voltage (or vice versa). This is achieved by approaching the maximum power point tracking (MPPT) operating point. However, in certain circumstances, it is not possible to increase or decrease the voltage sufficiently, resulting in a lack of optimal power generation for the specific shadowing condition. The shadowing of other panels affects the power produced by a panel due to the slow output current and the necessity for the optimizer to adapt its output current to the current of the string. This occurs while the optimizer attempts to counter the inverter's efforts to alter its apparent load in order to center the MPPT.
It is crucial to note that an essential parameter was not measured: the voltage entering the inverter. When the voltage drops below a certain threshold, the inverter is unable to track the MPPT, leading to complete shutdown.
Interesting, you only shade on the panel across the bottom half in some tests, how about if you shade half a panel from top to bottom?
Excellent and thorough testing. I know this took much time to plan, execute, and report, so many thanks. Optimizers cost ~50% of panel cost, so the gain of 10% is hard to pencil out, though many other considerations like other installation costs and limited space for panels.
Hi Martyna, was the SMA shade fix switched off on the Tigo optimized panels, and was it switched on for the non-optimized panels? Towards the end of the video some production data is shown from the SMA monitoring platform but it is not explained which shade setup is being used for this production data
Again, this would be case specific. So what are the extra cost per panel if you include the optimizers ? If you have no more space on the roof..possible a true advantage if you calculate around 1.2KW/h per day in saved cost. But if you have enough space on the roof, what would be the result if you would have gone with a slightly larger system at parity cost?
In both of your videos about optimisers, we are not shown the total amperage of each array which is fundamental in order to, not only understand but also evaluate the effect of installed optimisers. Perhaps if you have that data and you could briefly share it with us, we would very much appreciate it. 🙏Thanks for sharing your tests.
This test actually shows the advantage (also for safety) of using a simple bypass diode in parallel with the solar cell groups. in order for the solar module to be efficient all the cells in a series circuit need to be producing the same voltage/amperage. If they are not the cells that are lacking become more resistive and produce heat. Heat is wasted energy and it can damage the non producing cell (even burn). Non producing cells in a string also start to have more characteristics that of an LED then a solar cell. If you could get the non producing cell from a string under load in a dark place you would actually see it give off some light as well. this reverse flow (biasing) is what causes loss in the string. it is also not good for the cell. A bypass diode gives another path for the electricity to flow. The theory is that the voltage will flow first through the path of least resistance. As the non producing cells heat up, they get more resistive and eventually the diode becomes the more prominent path. But, also bypass diodes create some voltage loss as well. Schottky diodes are used for bypass diodes in solar modules because they have higher series resistance then other type diodes and keep the reverse voltages at safer levels. Another use for diodes in a solar circuit is a blocking diode which blocks an entire module or string. Bypass diodes are installed in parallel, blocking diodes are installed in a series circuit. Thanks for all that you do!
Thank you so much for sharing that information! Really valuable knowledge! Thank you again! :)
Great video - thanks! Just to clarify, I assume the voltage and current measurements are made on the panel side of the optimizers and the monitoring electronics. On the inverter side of those devices, the current in each unit has to be the same since they are connected in series.
Correct.
Exactly! The units measure the current on the input of the optimizers/ rapid shutdown device. Hence the current has different values. Its like seeing all panels in isolation.
Hi Martyna, how about shingled panels? Does there any reliable shingled panels that can perform better compred to half-cut with optimizer? How about the cost comparison with half-cut+optimizer and shingled panels?
Question: You refer to "Ever Since Bypass Diodes Became Used In Panels", since when was this? I cannot find this on the web. Your tests show that Panels with Bypass Diodes do not shut down the series string but what about older panels? I think it was is true with older panels, but how old is old?
i've seen demonstrations that showed that the optimizers don't work at all, and actually produce less power.
It seems it is because of the 'blind deployment" without CCA+TAP. It's also related to a particular firmware from 2021, and not sure if that issue still exists. I'm very interested to know whether you tested "blind" or with CCA+TAP, and whether you found the TS4 to misbehave in any situations.
I don't undertstand: Are the panels in each string wired is series (in which case I expect then to all have the same current) or parallel (in which case I expect them to have the same voltage), or what?
One of the most comprehensive and detailed explanation I have seen on this matter. This was beyond valuable. Thank you so much for sharing!
Thank you so much for saying that! I appreciate it!
Great video! Really helped me understand all this! This past summer I had a PV system installed on my house in San Antonio. It has 25 panels with mini-inverters and an Enphase system. The house does get significant shading from trees. I am already wanting to expand it. I do not have battery back-up but am considering installing it eventually. Also, the original installer (whom I shall never use again or recommend!) said there was no way to get power out of the system during a grid failure without a battery system, but as I understand it, there actually IS a device which allows for this. Do you know anything about that? Finally, the roof on my house is a low pitch standing seam metal roof. The current panels are installed on the south facing side. If I install panels on the north facing side would there be anything to gain by using a rack that will prop the panels up to an optimum south facing angle, especially if those are bifacial? (Roof is plain silver color)
Thanks again for your great, informative videos!
You need to "island" your system if you want it to work while the grid is down, the inverter needs the grid frequency to have power so you will have to have something to provide this. Other than a battery system I don't know whats available in the US to do this. Im in Australia and have sold solar since 2011 but inverters/ micro inverters work the same anywhere so thats the issue you face
Hi! I am so sorry for the delay in responding to you.
So yes, there is an option to use power during the grid outage with enphase.
I will include the link
enphase.com/homeowners/sunlight-backup-user-guide?hsa_acc=1236416428&hsa_cam=20130257651&hsa_grp=&hsa_ad=&hsa_src=x&hsa_tgt=&hsa_kw=&hsa_mt=&hsa_net=google&hsa_ver=3&gad=1&gclid=CjwKCAjws9ipBhB1EiwAccEi1Ld_T4TDI6NVlLA4375BrzzSQ9S33Y1lcXp6b6okeMKnX7FlpZXgCBoCvmIQAvD_BwE
The downside is it’s like having a battery set up ( cost of extra equipment) but no battery. I don’t think it’s worth the cost. It might cost over 4K maybe even close to 6k if there is a need for rewire. I suggest waiting till you get a battery becasue you will spend money once and have a good back up solution.
As far as pitching panels, you can email me and I can check the roof and see if that would make sense. The struggle here is that when you pitch panels you have to have spacing between them since they will start shading one another so you’re limiting space, and by just installing them facing north might cost similar to just have more panels, than less but a pitch.
Email me if you want me to review the address :) happy to help, again so sorry for my delayed response.
Info@solartimeusa.com
On DIYSolar forum, a person was getting a whole string shutdown in a different shade environment. No optimizers on the string. After a lot of testing it appears like the bypass diodes were not working. Doing tests like yours, they did work.
Although I absolutely applaud you trying to do objective tests, those of us with statistics background know about “lurking variables”. In this case, those lurking variables we know would be different panels, different bypass diodes, different shade profiles, etc. (but there are many other variables we don’t know about”.) Trees and filtered light will NOT work in the same way as your “leaf” and cardboard tests. Still, there was some learning here. May want to simulate real life partial shading on the next test.
Are the costs of the optimizers more, or less expensive than adding 10% more modules?
Tigo optimizers cost me $22/panel on a 44 panel system and produce a 6.4% improvement in generation for 1.5% increase in total system cost. ROI in the Tigo optimizers is 4.4 years while it's closer to 13 on the whole system.
Additionally, sometimes adding 6% extra panels is not just a roof space issue but a string configuration issue, ie. You can't just add another panel to a 2x12 string.
@@greg_takacs You seem to know very well the ins and outs of these system!
I just created a mini nuclear reactor in my garage so all is well.
You bought an EV😂
@@sirjohng1 you didn’t 😂
No you didn't
Can you do it again with half-cut panels? Ideally once vertically and once horizontally mounted with a flagpole shadow and a wide diffuse tree shadow sweeping across a full module?
I suspect half cut modules are better mounted horizontally so a horizontally moving thin shadow only shuts down half a panel at most. But a tree shadow would be way more interesting.
Hey this is amazing! I’m really struggling to pick between a local installer and Tesla here in upstate New York. For a same sized system Tesla is estimating. 6300kWh / year but the local installer is estimating 9478kWh/ year. Whose right! I even did a shading analysis in helioscope and the local installer was much closer it seems. Why is Tesla estimate so low? Is it cause of their string inverter vs local installers micros? Thanks!
Hey! I would say go local, if the company has good reputation, good online reviews and if they have been around for some time.
Does the installer offer any production warranty?
Tesla is undershooting so they don’t have to deal with complaints if underproduction later on. So they are playing safe.
The biggest problem I see with Tesla is service. In DFW in texas I service Tesla systems weekly at a charge becasue of how long they wait for service from Tesla. So if you can choose an installer that will service your system in the future, that’s the way to go. Local company might have a more expensive price but you’re also supporting local over huge corpo where nobody cares about you.
I am biased because I am a local business too. But I think you will be better off going local if company is reputable.
I hope this helps 🙌🏼
I would love for you to do this with the Enphase system vs string inverter vs power optimizers.
For test one, on the non-optimized side, was the leaf placed on the panel at the beginning of the series, or at the end of the series of that string?
Is the boost with it $/kWh vs just spending the optimizer $$$ on hanging more cheap solar panels?
How were the panels connected and how did that affect your test
The panels were connected in two separate strings and in two separate inverters. Does that answer the question? That should not cause any changes in the tests as they were connected in an identical way.
This is really an amazing video. Thank you for actually performing tests and sharing real data. Regarding tests 10, 11 and 12 where the non optimized panels were higher on individual panels, I think this is not important and that the optimized panels are working together to produce overall more wattage with the same shade. Looking at just the shaded panels (wattage), Test 10: Optimizers 24+173+171=368 vs non-optimizers 0+195+100=295. Test 11 optimizers 170+191+191=552 vs non-optimizers 0+188+216=404, and Test 12 optimizers 174+196+194+193+193+173+193=1316 vs non-optimizers 0+213+201+198+213+0+105=930. For example, on test 10, 173+171=344 Watts vs 195+100=295 watts. You end up with more overall wattage because the 2 optimized panels matched each other even though looking at just one panel, 195>173.
If you are using a string inveter with all 8 panels in 1 string, how is it possible for shaded panels to have less current than the full-sun panels? My system is strings of 6 panels, and I thought optimizers were required to prevent a shaded panel from reducing the output of the other 5 panels in the string?
SO the way the optimizers work is the try to find ( in mathematical term) best PRODUCT of the two (voltage and current). Sometimes they have to lower the current to increase the overall production outcome.
Also the optimizers do provide the INPUT values, so whatever enters ine optimizer, not the outcome. So later on the string MPPT also equalizes the values to track the bets power point of production. I hope that made sense?
Martyna
At roughly $100 per panel to install Power Optimiser, works out to $1000 for a string of 10 panels, for that same $1000 you could purchase 5 more panels at roughly $200 per panel, giving you a string of 15, the output then would blitz the output of the 10 power optimised string, subject of course if you have the room for 5 extra panels.
I like that idea too! You just have to see if you have the space and least amount of shading, but very very good thinking!
Cześć, bardzo dobrze widać że dodanie Tigo tylko w wersji monitoringu do panela HalfCut zupełnie zmienia jego działanie. Diody bajpasowe nie powinny zadziałać po zasłonięciu połowy panela tylko prąd modułu powinien spaść o połowę - niestety w takim przypadku prąd całego stringu też by spadł o połowę więc dodanie Tigo bez optymalizacji to właściwie poprawia działanie całego tego systemu bo załącza się w nim wbudowana opcja bajpasu. Moduły HC sprawdzają się tylko z mikroinwerterami lub optymalizatorami.
Co da samego testu zacienienia to w przyszłości proszę postawić przed panelami cienką rurkę lub powiesić linkę symulującą przewody zasilania lub cienkie gałązki. Taki "soft shadow" ma druzgocący wpływ na pracę całego całego układu stringowego - cień jest na tyle mały że diody bajpasowe się nie aktywują, a spadek prądu całego stringu jest ogromny. W takich przypadkach widać dopiero zyski z optymalizacji.
Another very good informative video. Given the increased costs with MI/Optimizers and the extra components required for panel level monitoring and combiner boxes, which typically have only a 5 year warranty, would money be better spent on a couple more panels. I know, it depends... hahaha Curious about filtered shading such as tree branch or power line 20 ft away.
Yes! I definitely want to apply that sort of shading. And test with cloudy days etc.
if you look at tests 6-9 they have the building shadow applied and both sides were pulling out same power outputs! Little sneak peak into future video with filtered shading!!! 🙏
Compared to a rapid shutdown system, the cost for the optimizers is marginal ($10/panel + $500 for the controller/monitor). Tigo optimizers also carry 25 year warranty, not 5. Mine work exceptionally with a chimney on the south side and a 2nd story dormer and some trees on the west side.
@@greg_takacs Yes, more components required for Tigo which increases costs. And Tigo components such as Cloud Connect are only 5 year warranty. Same as Enphase Envoy and combiner box, 5 year. And if using SMA inverter, SMA makes it clear they do not support other manufacturers products. Not saying Tigo is bad. Its obvious that most customers have no idea what they are buying and are unable to make a full comparison.
Being an Admin of 16K members FB Solar PV Solutions group
I wish to share this presentation.
Thanks
Thanks so much for all the effort and continuously producing content of such high value!
I am so so glad it was helpful! I appreciate leaving the comment so much! :)
Greetings, I am currently residing in the state of Florida and employed in the field of construction. I am interested in exploring the possibility of collaborating on the construction project you mentioned. Would it be possible for us to have a discussion regarding this matter?
I am currently exploring the option of replacing our electrical service with a battery power bank for our job site trailer.
Just curious. How did you measure the output of the non-optimized panels? Nice video.
Hey! I used the Tigo Rapid shutdown devices, that offer monitoring and rapid shutdown feature, with supposedly no optimization :)
Her is the link:
www.tigoenergy.com/product/ts4-a-s
I'm not sure what that per-panel monitoring box is doing, but it is not behaving as series string of panels without those boxes. Interesting test none the less, but I don't think it will apply to a string without electronics at each panel.
Hey! Thank you for your comment. The units are called tigo Shut down devices. Supposedly they do not “condition” the power simply provide rapid shutdown and monitoring ( reading data) feature. But! I do want to test them compared to simple string inverter to test whether a string behaves like that or not.
I am curious myself.
Thanks again for leaving your thoughts! I appreciate it
The problem originally came from solar panels that do not have bypass diodes. So a leaf on a single panel would drop production on the whole string by that %. So the 20..30% drop would be for all panels due to the single leaf on a single panel.
The bypass diodes prevent this as you have clearly demonstrated. Thanks!
I do have 8 of these pre bypass diode panels, but they won't see leafs or antennas (230Wp), but my next panels might get shaded, but have bypass and are slightly more than 500Wp. And there will be about 40 of them instead of, because I hope that would cover my winter days instead of having to settle for a bio-diesel generator. (a 500Wp solar panel is around $125 these days, a bio diesel is about $1500 so in costs I can have 6 panels with 2 mppt's)
yes, exactly! Yet the industry keeps using that to sell their own products. Just want people to have proper facts! :) I actually want to test older panels too, we have some leftovers in the warehouse from 2015s and prior... could be a fun battle to see :D
THANK YOU for posting this! I’d no idea until y’all explained it to me in person. Optimizers are a much better option than microinvertors.
Glad it helped! Thanks for the comment!
Great video! Really helps solar customers understand the impact of shading on a system with or without optimizers.
I am so grateful and happy it was helpful! Thank you!
Great work !!! Best regards from Spain. As you said, the first real test I found in internet. In Spain 80% of the people use Hibrid Inverters, and in France 70% use Microinverters... Why ? No idea..
If you don't mine , I will post your videos on European forums. Best regards
Was SMA Shadefix from the inverter used in these tests?
Next test to try is SMA vs a few different inverters (GoodWe, fronius, Sungrow) under the same conditions against eachother.
I would also be very interested in the answer to this question: Was SMA Shadefix from the inverter used in these tests?
I would expect other results that make the optimizers look questionable.
ShadeFix is automatically turned on for all SMA inverters and YES I do really wnat to test two different settings, with and without shade fix and see how much effect it really has. But seeing these results I wonder how different it would be since bypass diodes would work before the power gets to the inverter. DEFINITELY WANT TO TEST THEIR THEORY! :)
See above :! :)
Have I missed something, but I am not clear if these are 8s or 8p strings. I think I would always string at high volts but with 8 panels you have 4s2p and 2s4p configurations to test, at least on the non inverter side
Also you should repeat the experiment on a day when sun is not 100%...winter sun is so useful in off grid use cases.
@@solartimeusa, are you sure that the SMA Shadefix was active? Fronius for example claim, that their shadow management is even better than optimizers.
So what’s the verdict worth specing tigo?
I think it will depend on the situation. I for example have east and west-facing roof, and I absolutely do not need them, but for the low cost of like 25-30$ you can get the rapid shutdown ones with the monitoring capability, so its a relatively low cost and I get to show off the monitoring. But for the optimization, I really do not need it, as no trees surround my home and the strings are divided.
Is that $30 for tigos or another brand/model? I like the idea of the monitoring benefit. Also what app is used to track it ?
I bet, if you compare "with optimizers" array with "no optimizers or bypass diodes" array - results would be so much different.
Since the bypass diode actually does its job as well, and it optimizes the power output of a whole string/array based on the switching off capabilities it has.
Please explain why the currents for the panels in the string without power optimizers are different, more or less, from each other even when completely un-shaded. Since the panels are all in series, each panel must generate the SAME current.
Hey Bob, great question. Tigo units measure the current on the input of the optimizer, not at the output. So coming into the optimizer, the input current is smaller, based on the panel itself, then the units do their job on the optimizer side. And on the side with the rapid shutdown devices the current passes through and is also equalized to the string current. So the monitoring is reading what is happening at the panel level not past the optimizer. Does that make sense?
@@solartimeusa I asked about the currents on the panels WITHOUT optimizers.
Hows the 8 string connected series or parallel?
Series :)
Fantastic. Thanks a lot! I just got my 18 panel installed with the tigos. Pretty sure there is not an actual ROI under my conditions. But the generated data and graphics are so cool :-)
Thats great to hear! HAPPY PRODUCING IN 2024! :)!!!
It would be interesting to do the shade-from-building testing with the panels in landscape mode. Most panels strip the regions along the long length of the panel for each area covered by a bypass diode. That means the panels will work better in horizontal placement as the sun goes up or down. (I don't know if the optimizers would make a difference though)
They did do that test, it's towards the middle of the video. Additionally you can read this thread with a lot of good info from me and my system regarding all kinds of shading my system experiences diysolarforum.com/threads/can-shading-be-dealt-with-by-parallel-strings.54317/
That is a very good point, I do wonder the same. Surprisingly panels that were shaded in half and didnt have optimizers, completely shut down, which makes the marketing for half cut cell panels BS? I really want to test that too.
@4:23 ...going from 87W to 157W is not 50% more; it is 80% more. And it cannot be said to be "up to" as there is only one data point.
Similarly, at 19:50, that's 12% more energy - not 10% more.
Hey David. This is a good point, but the percentages can be complicated, as easy as it sounds. The final percentage results from deciding which number is the starting number and new number.
For example if we are trying to calculate the increase from 87 watts to 157 watts.
Original Number is 87
New Number is 157
Formula
The increase -> 157-87 = 70
(70/87)x 100 = 80 %
But if we try to calculate decrease from 157 to 87 numbers change, and that is what I used.
Now if we flip it, and now
the original number is 157
New Number is 87
Formula
the Increase - 70
(70/157) x 100 = 45%
The question becomes which one is our point of reference... :)
@@solartimeusa It's not at all complicated. The question as to the point of reference was decided as soon as you referenced the "increase" in power.
If a value was 100 and then became 150, the increase is 50% ... not 33%. It is not questionable.
You are so right. I will make sure to make musre my point of reference is correct in the future. :)
Hi Martyna, or Martina? ;-) Nice video!! I only little bit don't what all these boxes are. You showed two smaller black boxes with some cables... Does it mean that each solar panel has one black box connected underneath (so there are 16 hidden boxes)? It would be nice to see wiring from back of panels. And you are speaking about diods - are they in those black boxes or are they built-in solar panels? It would be nice to see some theory first (for such beginners like me) - like wiring diagram of both configurations. (If black boxes are placed in both strings, then it would be nice to have third string without any black boxes - 5 panels in each string is enough, no need for 8.) And I'd love to see what each black box actually do. Now I maybe understand that first black box if only for measuring current and voltage but is passive - doesn't do anything. (if so, then 3 strings doesn't make any sense) And second with optimizer is basically acting like tranzistor which is connected in parallel to panel and if there is shadow (power drop down + increasing internal resistence of solar panel), it opens itself partially and allows bypassing current from other panels from the string? (Btw excellent clear English, I am CZ and can't hear almost any accent.)
Hey! Its Martyna ( Polish) but when pronouncing it in english it is pronounced like Martina.
Yes so each panel has a small back box behind, that is built in, and it includes the bypass diodes. Then what I did is used 8 power optimizers ( extra black boxes) under one set of panels, and 8 Rapid shutdown devices ( extra black box) under the other eight. I would love to dig deeper into how they are wired, hopefully in the future video. But in an easyway speaking the panels have their connectors that connect to power optimizers ( male and female connectors) and then those then connect in series to other panels.
There are two ways of connecting panels together either in series or in parallel. I definitely want to do a video on that, so make sure to subscribe :)!
Thank you for leaving the comment!
Great video.....very useful. next video idea is panel facing planning. I have 5 quote and they layout are all different....how to make decision
Oh wow! You know you can email me directly and I can try to help you determine which one is most realistic!
I do consulting for homeowners outside of my work area :)
Info@solartimeusa.com
Not so concerned about individual panel knock downs, but total power output of whole string.
I would like to see this repeated with two strings in parallel like Tesla Solar Loves to do.
I would like to see how different azimuths and pitch’s affect daily production on a single string.
I cant wait to do some of those tests with newest PW3....:D
Can you actually know which panel is underperforming without monitoring hardware... Because if i have to pay for the monitoring hardware you used then i might as well get optimisers
Yes and no.
If you have a string inverter with no optimizers or no monitoring devices, then you can see drops in particular sting's voltage at the inverter screen. So you can identify the string ( group of panels) that might have an issue.
The problem is that panels DO NOT FAIL. They don't have moving parts or sophisticated electronics. Usually is the microinverter or optimizer that fails... so you have it there to see which one fails. Its almost funny as I write it.
I feel like its the marketing of panel level monitoring is what made us think if you have a panel level device, then you know when the panel fails, well they dont ... :D at least not very often.
@@solartimeusa thank you so much for your response.... It wasn't really about failure... More so that I could identify where I have an issue with shading or whatever(I'm sure I'd spot a leaf😁) your videos have been very helpful and informative... I plan to buy a home next year so I'm trying to find out as much as I can. I was leaning towards not using microinverters or optimisers after watching your video... My only concern was monitoring but if it's not a big deal I'd rather not spend what I don't need to
This looked like a test of panels in parallel, mit series. Can you confirm? Id like to see the same test in series. Likely verry different
Series... :) I connected 8 panels in series to one string input in SMA Sunny boy, and the other 8 in series into a second, separate SMA Sunny boy.
I don't have solar yet but trying to learn. So my question here is. Would it be more effective to buy 8 Optimizers or 1 more solar panel?
That is a very good question!!! And the problem is the answer is not super straightforward. This will definitely depend on the severity of shading. In some cases shading is so minimal that it wouldn't be worth it, sometimes space is limited so power optimizers are the better option.
Very impressive test!
Constructive criticism: if testing partially shaded panels, it would be far more reliable and scientifically correct to use a jig to accurately position the leaves so they cover exactly the same amount of the same cells in each panel. It may or may not affect the results, but at least you’ve eliminated a variable.
Keep up the good work!
Thank you so much for the feedback! I do agree and appreciate it! I will try to be super detailed with tests coming out this summer. :)\
@@solartimeusa making tape “loops” and keeping the tape completely behind the obstruction would also be a good idea.
Thanks for the reply, it’s great to see creators who engage with the comments! 👍
How were the panels hooked up in series or parallel?
Series :)
Thank you for this test. I recently watched another video suggesting far less of an impact on string shading, but their test method, presentation, and conclusions were already suspect to me.
Thank you! I plan on doing other tests with similar shading but also with different brand inverters. I also want to test more filtered shading like trees. :) I am curious if results will be similar or very different.
Interesting stuff. You're right, the repeated narrative over and over has been, shade one panel on a string and the rest only produce the amount of the shaded panel. Obviously, this isn't necessarily the case.
Do the brand of panel and maybe age of panels make this hypothesis different?
I would like to see a test of two systems with mixed panel wattages and see what that does on a string system. That's another thing that is always repeated as a no-no, never mix wattages. How would that look in this same test?
Thanks for the feedback, and yes that would be a really cool test, to mix brands and panel voltages. Like adding a 480W panel to a 400 w panel string! Thanks for the idea!!! :)
Another benefit of optimizers is the ability to mix different panels within a string (within reason). Note that the Tigo optimizers are buck converters not buck/boost converters therefore they can only turn higher voltage lower current into lower voltage and higher current, not the other way around. This generally is fine unless you're starting to look at and work with uneven size parallel strings going to the same inverter input and the likes ;-).
I think the real test is to run them side by side for an extended period of time. Don’t forget that modules and components within the modules will deteriorate over time - this will have a huge impact on performance as time passes by. Not to mention cloud cover and soiling which are inevitable.
The inverter’s role really starts to pay off not on day one but over the 15 to 20 year life span of the system. Nearly every test I’ve seen on the subject does not cover the subject of long term yield
That’s the most amazing real life pv test on YT. I was expecting perhaps 2-3% if anything at all.
Would you compare optimisers to microinverters?
Have you seen it yet? Just posted that this weekend!! :)
Thanks! I can explain the worries about "one shaded panel affects the others". You can see the data with your own tests, but the measuring devices/timing are very imprecise, so it wasn't obvious. When batteries/panels are connected in series (string) and you put a load, _exactly_ the same current passes through all batteries. No exceptions. The power-meters here you can see are not good, reporting 7.93A on one panel but 7.99A on another and 8.05 on another. That is physically impossible. It's possible that they are precise but the measurement+reporting happened a few milliseconds apart in time instead of simultaneously. Anyway, when one panel can do only 3.99A 36V due to shading, you can't possibly get more or less current than 3.99A from any other panel. So that's why people are worried that suddenly the whole string would produce half the amps thus half the wattage. Instead, the MPPT tries to draw different amount of input current, to find the sweet-spot. It tries 8.01A, the voltage of the shaded section rapidly falls below 0.6V as it can't meet demand, its diode turns on and the remaining 2 sections of a panel now output 8.01A 24V together. All panels resume to run at 8.01A, and the total voltage is simply 12V less. So, with 10 panels you don't lose half the total wattage (getting 3.99 x 36 x 10 = 1436.4W instead of 2883.6W). You only lose 12x8.01 = 96.12W, you get 360-12=348V 8.01A instead of the full 360V 8.01A. You see this in all your tests: all panels produce around 7-8A, and some of the sections of panels get turned-off, producing 0V and 7-8A. Well actually each diode that turned-on eats 0.6V * 8 = 4.8W and turns it into heat. The reported voltages on fully-shaded panels seem incorrect. It shouldn't be 40V 0A but 0V 8A. Actually -1.8V 8A. It must be a software bug.
The bypass diodes ensure that suboptimal sections of the panels are turned off. The MPPT does a good job of finding the optimal current to use from the remaining turned-on sections. The resulting voltage of each section depends on that current (e.g 9V at 8.6A or 12V at 8.01A).
Solar panels come with optimizers built-in: those bypass diodes 😤. A future improvement would be: remove the bypass diodes, and connect a new kind of optimizer with 4 wires to the panel. Optimize each section independently. I don't see it happening any time, soon, though. Currently the optimizers get crippled by the bypass diodes.
Hey!!! Thank you so much for the thoughts and input! I should have explained in the video that the Tigo units dont measure the OUTPUT of the optimizers/rapid shutdown units. It is measuring the input from the panel itself, so we can see them all separately in isolation. So the actual current of the string is the equalized by the mmpt in the string inverter itself, so I can totally see how that seemed misleading. What I learned from Tigo ( as much as they could tell me) is the units measure the input not the output of the unit itself. But this LEADS me to ANOTHER TEST! Lets see if I put 8 panels with the TS4S ( no optimization) and just string inverter with no units under the panels, and compare the outcomes. I am very curious how the results will vary, and if they will.
I do like your idea too!!! Hopefully one day! :)
Martyna
@@solartimeusa You may be interested to learn that Tigo record both Vin and Vout for each panel, but for some reason Vout isn't made available directly in their charting application. Good news is that you can just edit the URL, adding '&suffixes[]=vout'. The data is also available via their API.
panels have an efficiency, an amount they can generate for a given amount of sun. cover half a panel, IE give it half as much sun, you will get half as much production, no magic box you can buy to add onto a panel will or can change that.
top say that covering half a panel and yet still get 3/4s the power, means your changing the efficency, and thats not really possible.
when panels are in series then 'per panel bypass diodes' are the only option available to you, per cell bypass diodes cant be added after the panel is built.
best cure for localised shading, micro-inverters to ac or individual mppt->dc->boost to a dc bus
Great content Martyna. Keep the videos coming. Thank you
Thank you sir for leaving a comment and words of encouragement. :) Appreciate it!
nice videos. I would have made sense to spend a minute at the beginning showing the sub-strings layout on these panels, if they are half-cut cells and explain how many bypass diodes they have.
Very fair point, thank you so much for the tips. I am working on a ton of tests coming out this summer, so I will make sure to be much more detailed.
A bifurcated panel test would be interesting. I have a customer who wants ground mounted but doesn't have the space.
oh yes!!! I really want to get that done soon! Thank you for the idea. I have some in stock too that are 480W QCELLS.
Great video!
It would have been great to include Fronius - it is known for its ability to handle shades better than optimizers.
I really want to test fronius ability to optimize string, a few people asked about it too! That would be a very good test! I am definitely starting lots of tests this month! :)
It makes no sense that some of the currents on the "no optimizers" panels at 3:32 are different from each other. The high is 7.23 Amps while the low is 6.97 amps. They should all be the same because all the panels are electrically in series.
Hey Bob! You are very correct, the power optimizer and the shutdown units, are measuring the input not the panel, then the current is equalized on the string mppt level. Hope that explains that. :)
Thanks for sharing your thoughts and concerns.
@@solartimeusa I'm sorry but you don't understand the basics of electronics. The current readings from the "shutdown units" should all be EXACTLY the same. Good luck to you.....
@@bobhilder1469 Bob I just realized in my message I had a typo above, I said “not the panel” what I meant “ off the panel”.
Shutdown units are measuring current OFF THE PANEL at the input level of the device, not the output of the device.
Not the current of the string as a whole.
Also the measurements are done in the unknown way, when I asked tigo how it’s done they couldn’t explain it without breach of their proprietary technology.
And this is the way they also explain it to me, same as I did to you.
I only have shading in AM/PM when sun moves into field of panels or out of field. My neighbor has string inverters with optimizers which cost more than I paid for each panel. I bought used. Adding more panels and another inverter for me or anyone with no shading is the way to go if they also have a all in one inverter like I do which is 2 5k inverters.
Thank you for sharing! Yes unless there is substantial shading I would not worry too much about the optimization whatsoever! Thank you for leaving a comment.
can you mix optimizer and no optimizer? say you know you'll only have shading on 3 of the 8 panels..
With Tigo you can, but I am not sure for other options. I should test other agnostic optimizer options. :)
what about dust and plant pollen
Good idea! I do plant do dirt up some panels and test that as well! Super good idea!
I really think spending your $ on more photovoltaic surface are has a better ROI than spending $$ on extra subsystems like optimizers. A optimizer costs near the same as a 2nd panel for only a 10% gain, where 2 panels is a 100% gain for the same cost?
The best panel video ever.
Thank you so so much!
good job, very informative. deserves more views and top search results
Thank you so much for the kind words. I so appreciate it. I am just starting my youtube venture, so I hope in the future youtube algorithm will pick things up more! :)
The tests show that your money is better invested in more solar panels than optimizers.
The panels will likely last for decades while anything electronic is looking for an opportunity to fail.
Of course,ground mount is better regardless of optimizers or not because of ease of maintenance.
Very very fair point, lots of people feel same way, the only issue in usa is the rapid shutdown law.. that makes us use some sort of panel level device for rapid shutdown ; /
Can someone help me understand why natural shade has no effect but artificial blockage does?
A ground mount system, without tree shading, but in a cold climate where snow might shade a panel, optimizers should be a benefit.
Yes definitely. I do see big benefit in them, just for the most cost effective solution, sometimes not needed. Thanks for sharing your thoughts, I appreciate the comment! :)
It looks that, when more than 70% or 80% of the panels are covered by shadows in a string, the optimisers just try to work at a medium level of current and voltage for all the serie.
So now that you've dispelled the perception that micro inverters do not have a big advantage what other advantages are there for string inverters? I'm planning on installing a solar system but keep flip flopping back and forth between the different type of systems.
ua-cam.com/video/4K_q7hGFLuo/v-deo.htmlsi=AgS9wA0VBgt8c6c2 i did a video a few weeks ago comparing micro versus string! That would be a great start
I think the benefit is not with a string inverter but with a hybrid inverter, one that can handle DC coupled batteries and whole house loads without the need of a critical load panel. These are obviously larger and more expensive that throwing a handful of panels with micro inverters on the roof but they provide far more utility and lower overall cost when you factor everything in. Adding batteries to a micro inverter setup is buying the inverters for the batteries all over again.
@@solartimeusa Do you guys do any installs in the Austin area?
What about CIGS Panels?
That's a good idea to test thin film panels! I do see their applications on camping and RV trips, not as much for residential homes, but definitely want to test their ABILITIES! :)
one thing is missing to me... The test was o so great... what about to take the same money what optimizers costs and buy more panels without them and try that comparison (what do you get for your money).
Yes very good point! I’m actually testing other equipment like microinverters now. But definitely want to test different shading type like filtered shading from trees etc. stay tuned ! And thanks so much for leaving a comment! It helps me so much!
Awesome and very useful testing.
Thank you so much! :) I am very glad!!
You have just answer my question that I posted in another video of yours regarding the need of optimizers in set up with no shading issues. I guess that uneven panel degradation over time and / or dirt accumulation on the panels play no practical role on the question optimizers or no optimizers. That is, because we are talking long term.
Regarding the existence of the Tygo panel level emergency shut down modules on the no optimizer side of the test panels, these modules are just switches, hence their cheaper prices. Tygo introduced this solution in order to serve consumers who have some Code to abide to but not necessarily have shading or monitoring concerns. Being , nothing more than switches, they introduce extra resistance in the circuit as opposed to a straight wire connection. Therefore, your test results are 110% valid and actually on the conservative side as far the performance of the no optimization panel side. If you remove these switches completely on that side, the panel output will be slightly higher than with the cutout switches on.
I am so sorry I missed your other comment. I really try to respond to them all! :(
But thank you so much for leaving your questions and feedback and thoughts, it helps me a ton, and obviously, I love to know if I make any mistakes while we test those different products, so I can improve and keep learning.
What a great video, thank you very much for the transparency and honesty,
The way you explained it was so easy to understand.
Looking forward to watch your next vids.
Thank YOU so much for saying that. Means so much to me it was helpful!!!
Where space is not constrained you can probably install extra solar panels with the money saved from not using micro inverters. This is especially relevant for ground mount systems.
YES! so so true!
YES! so so true!
Togo optimizers don’t have a buck or boost circuit between the mppt and the string. So on Test twelve, fifth panel, the current is being limited on the first panel to the same as the others on the string. All current on a string has to be EQUAL on the string.
I really want to see this test repeated with a string of enphase inverters.
I did! :) Here is a link: ua-cam.com/video/KFOM2SQ_qNM/v-deo.html&lc=UgzbadBPlFaostf6fK94AaABAg
Can you repeat test 12 exactly with enphase in mix.