Hi. In a previous video, you saw how I got a upgraded home solar system from three kilowatts to eight kilowatts. And it's the quotation marks we're going to talk about today because thanks to Lg, I got 14 uh, brand new 370 watt neon 2 panels. These were a pretty big upgrade from my the existing system I installed back in 2013.

I think it was like over seven almost eight years ago. Now they were 250 watt panels and I had 12 of them. Now I've got 14 370 watts and I've also got both systems running side by side. So I've got 5.1 kilowatts with these new ones nominal in quote marks.

This is what this video is about. and the existing three kill three kilowatt system. And a lot of people uh, pointed out in the comments to this video that hey, you're not actually going to get the full 370 watts out of these, you're only going to get 295 watt maximum. Why is it? So it's not just about solar insulation or solar irradiance as you call it, I.e, the amount of sun hitting the panels.

Because I'm in Sydney here, and well, our sun is notoriously harsh and we do actually get the nominal thousand watts per square meter or more. Uh, on certain days. So it certainly is possible to get 370 watts out of this. But as a lot of people pointed out, the um enphase micro inverters are supplied.

These are the Iq7 plus other ones that I got, and a lot of people point out that these are only 295 watt peak inverters. And sure enough, they Are correct. If you go down here in the data sheet and here it is the Iq7 Plus so it says here commonly used module parents I.e what panels Is it suitable for panels from 235 watts to 440 watts in 60 cell, 72 cell configurations, blah blah or your maximum voltages, currents, and everything else. But down here.

Sure enough, peak output power: 295 va volts times amps. That's what's right. let's just ignore any phase stuff. 295 watts peak output power and a maximum continuous output power of 290 va.

So I didn't actually know about how it's very common in the industry to actually do this because here in Australia it's very typical. uh, like most people will probably use like a string inverter like the I got the Sunny Boy inverter when I installed my three kilowatt system before 12 times. Uh, 250 watts is three kilowatts exactly. I installed a three kilowatt inverter and that's a common as mud here in Australia.

that's you know, pretty much standard industry practice. We don't actually D-rate So it's an interesting question why you'd actually want a D-rate and it is an industry thing there's you know articles about this galore: How to maximize solar project value using inverter clipping some people claim, and probably rightly so that you might actually get increased energy output, not power. Increased energy output ie. power over time, increased energy output over the life of the system by actually using a D rated micro inverter ie.

a 295 watt micro inverter on a 370 watt panel. In this particular case, it's called the Dc to Ac ratio right here and for example it might be 1.4 to 1. in my case, it's 295 watts peak divided by 270. That's about 80 or a 1.25 Uh Dc to Ac ratio and that's act like actually fairly average in the market.

A lot of people claim and have seen systems or their own systems have been Uh D rated by uh like one 1.5 to 1 for example. So you know a much greater D rating and end phase themselves actually have a technical brief paper linked in down below for those playing along at home. Basically, it compares their highest output micro inverter, the Iq7a versus the Iq7 plus that I've got in Australia. They actually have done specific tests about this and this Uh D rating thing.

It's also called like oversizing. So you're oversizing the panels based on your inverter, so you might have you know a five kilowatt worth of panels and you'll only get a three and a half or four kilowatt inverter. In my particular case, I've got uh, just over 5.1 kilowatts of Uh nominal panel power will go into that versus the inverters which are a total of at 295 watts times 14 uh 4.13 kilowatts total. So apparently the Cee states that the inverter nominal Ac output power cannot be less than 75 of the array peak.

So I'm at about 80 percent. So I'm above this uh, nominal Cec Uh figure. So 133 percent oversizing from Dc input output power. However, Pd's designers and installers are often concerned about clipping and the associated power losses if they oversize the Dc up to the full 133 percent.

So this technical brief uh, it goes into a 25 year life span of the system and stuff like that and does some measurements and estimates are the maximum energy over time basically. uh, the Iq 7a, which is a 349 watt peak. So even their highest output micro inverter can't actually match my 370 watt panels for a 000 watt per square meter solar insulation or solar irradiance. So it's It's interesting, but they've got all sorts of things showing you how you know this is like standard in industry practice.

But the bottom line is, will my 290 watt peak micro inverters clip on my 370 watt panels? Well, the answer is here in Sydney with my elevation and everything else. Yes, it will clip, but how many days average per year will it clip and how much impact will that make on my actual and the total energy output over the year? Because ultimately, that's all you care about if you're clipping a little bit per day, but you gain some extra percentage. efficiency increases somewhere else as we might talk about then hey, you might actually get more from your system by actually de-rating it like this, or over-sizing your system or under-sizing your micro-inverters compared to your panel. So stick around for the end because I am going to show you some data that I've got on my old system which will apply to my new system and will answer the question of how many days out of the year.

Or we can roughly expect my micro inverters to clip the output at 295 watts. And let's go down to the data. Electrical Properties Now, Electrical Properties is two types. This is the Stc or standard testing conditions and the electrical properties are Nmot.

That's a nominal module operating temperature, right? and they specify these at different solar irradiance. So the Stc panels when you buy them, the marketing spec is or pretty much always the Stc or Standard testing conditions which assumes that you're going to get a thousand watts per square meter, solar irradiance, or solar insulation. The sun is going to put that amount of power into your panels. But down here, if you use the Nmot uh, electrical properties, then it it only assumes 8 800 watts per square meter.

And by coincidence that that just so happens to be where my Iq7 plus end phase micro inverters are rated in comparison to that. but how many days a year will I get over 800 watts per square meter and they'll actually clip? There it is 370 watts output at a thousand square meters or at 800 watts per square meters, you're going to get 277 watts output from each panel, so that's actually comfortably under the 295 watts peak. So those Iq7 plus micro inverters? if you're only getting 800 watts per square meter? Sure enough, I like these in micro inverters and never clip. There's no point of buying more expensive and higher rated output power micro inverters if you're not getting that sort of solar insulation.

But anyway, I don't really have a choice because end phase don't actually manufacture a 370 watt output micro inverter, and it's a pretty safe bet that if they did, it's going to be significantly more expensive than the 295 watt Iq7 plus version because you know it's really difficult to design these things and over temperature and you know all sorts of stuff. Apparently you can actually get micro inverters rated uh, for 370 watts or more, or 400 watts from other manufacturers, but are they worth it? Well, I don't know. Let's look at some data, let's have some fun. so let's just have a quick look here.

There's a many places you can get solar irradiance data or solar installation data. I think this one's cool though. This is actually a live map 14. Uh, no, this is six oh Six of April actually updated for today and you can see it sweep across Australia like this and you'll notice that the graph down the bottom down here is up to a thousand watts per square meter.

So so if you see it go really pinky pink pink, then you know you're getting a thousand watts per square meter. So Sydney, you know around about here somewhere? Yep, Yep. Yep, it's getting pinky pinky. But you know clouds and everything else get in the way.

If you're installing these panels in the top of Australia a good Latin part of the year, you're probably going to be getting your thousand watts, uh, per square meter. or you know, like 900 and something. But granted, we are in April here now, so we're well out of summer. But having said that, let's have a look at some data here, shall we? This is my new end phase system and if you're following me on Twitter and you should, if you want updates on all this sort of stuff, you'll notice that the orange one here is the consumption and it's going negative.

and there's a reason why it's negative here and I fixed it. As you can see over here, I'm now like at the moment right now. Um, my house is only consuming 168 watts. There you go.

We've got two fridges running nothing else, nobody's home and the blue one there is, it's current. My system is currently generating 5.196 but don't get excited because I also made a change about on this day here that this blue output now includes both of my systems. so it includes the end phase one at five kilowatts. Plus it includes the three existing three kilowatt system as well.

These days back here do not show that. So if you can see here, I did actually clip. Well, let's get the confuser out. 295 times 14 equals 4.13 We got 4.172 so you know there's a little bit of measurement there and all sorts of stuff.

But basically on a day in April, my system has basically hit the limit. End phase micro inverter solution using the Iq7 Plus, inverters will never output more than that. That's the maximum I will ever get, even during the peak of summer the biggest solar irradiance day possible. Yeah, it just won't get more than 4.12 for my 5.1 kilowatt system.

And I've got to admit, I've kind of find that as an engineer, I find that a bit offensive, you know, but it always comes down to practicality. How much do you want to pay for your inverter system? Is it worth paying where just to get a little peek on? you know, a couple of dozen days a year or something like that, right? Is it worth it? And then it only peaks. You know it should look a nice smooth curve like this, but the sun came in and out and etc. and I had these issues here.

So really, it's only the T. If you're going to clip, it's only going to be the tip. So you're only losing a relative like single digit percentages of your daily output on the most extreme days. And this is why many people will actually uh, under you know over rate or d rate their uh sister inverter system compared to their panels.

Especially if you live in in another country, let's choose another country. United Kingdom. Here we go. Uk is pretty crap for sun, isn't it? Oh yeah, there we go.

Yeah, it's not. Oh a pink. A little bit of pink, a little bit of pink. but it's not like extreme pink.

Well, it's not doing too bad. You might get like maybe 800 watts at the moment. Now shut up Dave. show us the data that you've analyzed.

Well, Okay, um, if you go to this article here it says you know it makes a claim because panels really produce as much power as their rated capacity is. It is possible to ed add extra panels with very little power being lost. Extra capacity, blah blah blah blah. And somebody on Twitter brought this up and I've contacted in face themselves and they've said you know and not many days per year is going, you know in Sydney is going to be over, uh, that nominal? Uh, you know, 80 percent? Uh, figure.

So well. I've got an existing system here which I've been measuring for like the last seven and a half years. I think with the occasional data loss because I have to upload all this data manually bulk upload manually so I've missed a little bit. But anyway, I was able to take all this data analyzer.

And because I used Lg panels before and because my new system is in the you once again using Lg panels, but now 370 watts versus 250 nominally rated at a thousand watts per square meter in exactly the same like they're installed in exactly the same location, I can expect the exact same, basically the same results from my new five kilowatt system. as I got on my old three kilowatt system and Ta-da I have analyzed the data. What I got here. I outputted 1980 days worth of data down here, and as I said, there's a few missing days, But basically this system did give out the peak power now because it samples it well.

It gives that figure every five minutes, so I don't know what happens within that five minutes. If it actually peaks hot, you know, does it actually take the peak within the five minutes? I'm not actually sure. But anyway, um, you know, this is pretty good data that we've got over 1980 days. So that takes in many years and all the seasonal variations and everything else.

And I've actually sorted this from lower. so the lowest is 96 watts total system output from my three kilowatt system all the way with Lbj right up to. Come on, you can do it there. It is right up to three kilowatts.

Yes, my system did. actually my nominal three kilowatt system did actually output three kilowatts on like seven days out of that whole lot. Um, and and then it got very close on lots of them. But how many days and how many over that eighty percent figure ie.

how you know, with my new system with the 295 watt micro inverters that clips at 4.13 kilowatts, how can how many days over the life of my system can we explore per year roughly, can we expect them to actually clip? Well, I've done my histogram here and let's take a look at it. So it took all that data and on the y axis here. this is the number of days occurrence that gave an output on the X-axis here within this bin. All right, So I've been them.

So this highest peak here. There were 210 days here that outputted between 2 396 watts and 2 496 watts. Geez, I should have made that an even multiple shouldn't I? uh. Anyway, so if my system will only ever, according to the end phase data sheet, ever output 4.13 kilowatts maximum, then we can actually work out because this is a three kilowatt system.

But we can extrapolate that to the five kilowatt system. so 14 times 370 watts, Which we know we can actually get the solar insulation. We can actually get 370 watts out of each one of those panels. Damn it.

So 5180 times? Uh, not 0.8 or 80 4144. Um, which turns out to be 3 000 times 80 percent 2400. So it translates to 2400. So basically it'll be the largest one here and all these additional days.

On all of these days, we can expect our new 5 kilowatt system to peak. How many days total is that? That is 709 days out of not 1980 days or around about. you know, 38 percent. We're pushing 40 percent of days.

Over the all the time I've been measuring this that we, we can expect my new in-phase system to clip. So that's actually that's quite substantial. But once again, how much power am I actually losing? Well, unfortunately, I won't be able to cover that in this video because that is harder to analyze. but I'll see if I can find like a really good day that's close to that three kilowatt peak there.

Oh see, I get days like this like I haven't found one yet. that's perfect at, you know, no clouds. Perfect curve at three kilowatts, we can see like this one peaks here like you know, like it peaks right there at 2.93 You know, right at three so you can actually see there's if you extrapolate the curve. Anyway, I'll keep going.

See, you get perfect ones, but they're actually below three kilowatts even though it's only a week later. But the solar installation changes on a daily basis and that's the thing. You know. it can change like like 20 percent, but actually between days.

so it's quite substantial. And I know what you're saying. Dave, Just go to these perfect days here. You know they've got the most out.

It turns out most of them are only like little short peaks at that because the clouds are moving over. but it happens to be really high solar insulation on those days. So you get like extreme days like this, where like, like, it really is like it. Probably I might have even this day might have even clipped my existing three kilowatt inverter, for example, You notice there's a reason why some days like didn't get like they were actually kept at three kilowatts.

So technically my old system was clipped as well. You know, a handful of days and this looks like one of them. Like these peaks are way up there. really extreme stuff.

You get perfect days like this and they've got slow solar insulation. And by the way, you'll notice that, uh, these highest days? Um, here they're But once again, obviously they're in summer. They're anywhere from like, oh, you know, latest October through to like March and things like that. But you know, yeah, it's pretty much you know, over summer as you'd expect when summer here, of course, is uh, December through to uh, end of February and I think 2017 seems to be a particular year.

There's actually quite a significant number of 2017s in here, so maybe I should check that out. Surely you can draw a smooth curve on the top of that one. Hold your tongue at the right angle. Okay, I'm I'm actually going to take this day here and then I'm just going to print it out and like draw a line over it.

It's just. ah, just done around. Okay, so let's just take that data. What I'll do is I'll print that out and then we'll draw a line over the top of that.

And then we'll estimate because it does peak at three kilowatts and we can extrapolate that to 5.1 kilowatts for the new system. We can work out like, you know, roughly what a percentage of you know, like energy over the day that we're going to lose because it's the area under the curve of course. Yes, I'm a green screen ta-da Here we go. Here's my dodgy as graph of the estimating five kilowatt uh system that we're going to get.

Obviously it's going to peak up here and I've drawn the 80 percent mark which is where my new micro inverters will, uh, peak and as you can see, it's a significant amount of the day. This is once again assuming that we get absolutely perfect sole insulation. We do get 370 watts out of the panels, so the nominal 5.1 something kilowatt system will only output 4.13 absolute maximum, but you can see it's a significant amount. Now if you compare, that is Sha red shaded area that's going to clip with the area or the area underneath here I don't know.

Work out. guesstimate. Hold your tongue at the right angle, have a shot at guessing um, how much that area is. Yes, it's in that line under there like that.

Just imagine it's nice and smooth. You might lose, you know, eight percent. You know, maybe pushing ten percent or something like that Once again, in Sydney or Northern Australia in a high solar installation area on a really good day. As I said, it can vary.

You know, I can get easily get you know, even big number of my days. In fact, the majority of my days as we saw only 40 under 40 percent of the days 38 of days are actually going to clip at all. Otherwise we'll be capturing everything. But um, in this particular case, like you might be wasting this little peak here.

This one here. You know these little peaks in there like that and it's not a big deal. So you might be thinking, well, if my inverter is going to clip on a good day, what is the point of buying these? you know, a really high output. Uh, you know, fancy fancy 370 watt or more panels? Why not just buy like cheaper panels if they still make them Because technology progresses and generally it's hard to find old stock.

But if you can, why not buy the cheaper ones? I'm here to tell you, that's a bad idea. Don't do it. Get the highest output panels that you can, of course, don't get absolutely bleeding edge because you might pay a real price premium. Get the best bang per buck.

Highest output panels that you can afford. Why? Because uh, you're not going to waste it. They're going to be. The higher output panels are going to be more efficient.

On the vast majority of, well, they're going to be more efficient all the time, but especially on the vast majority of the days when you aren't clipping and losing anything. So if you go for these like you know, or even if you could get them still, these older design panels, uh, you know, 340 watts? You know, 330 or 325 or something like that. Even if you could get 290s. No, don't do it because these are exactly the same size panels.

so you're not gaining any like space or anything like that. But they're simply less efficient. You get like 340 watts or 325 watts at a thousand watts per square meter. Your solar radiance is going to be exactly the same.

So for even if you know, it's really bad today, you're only getting 500 watts per square meter, a couple hundred watts per square meter because it's really cloudy or whatever. You're going to get more out of the larger rated panels and your inverter is going to suck up all of that, uh, extra power. So yeah, you get the highest output rating panels you can. Let's say you had your heart set on these end phase micro inverters because they're really cool and you can only get like, you know, 290 watts or 340 watt ones which match, Uh, which happen to match these panels here.

If you get the seven plus, then no, don't fall into the trap. Over rate your system and get the larger panels. Don't let the choice of your inverter and dictate it because most of the time you are not going to get that absolutely perfect solar irradiance due to clouds natural variation from day to day. Even during the day, it can vary a lot and even if you are going to clip a bit, you're still going to get a huge advantage from getting the larger panels.

That's why people over rate this system and I believe this is common in Europe. and leave it down below where you know you've got no chance in hell of getting your 370 watts out of your 370 watt panel Ever. So if you want like a 5 kilowatt system, you install 10 kilowatts nominal worth of panels. So yeah, that's a bit of a bummer.

but here in Australia yeah, no workers. We'll get our 10 kilowatts on a good day. Now I said before that this, uh, inverter clipping? um, there are other advantages because technically overrate your panels compared to your mic or Ied rate your micro inverter compared to your nominal panel output. Then it might actually operate more efficiently at the extreme.

so you might actually gain the extra efficiency in there. Plus, of course, because you're using micro inverters you're going to gain. You can actually see the individual rays like this one over here is partially shaded. so this one before it would actually bring the entire string down.

Say on some graph like this. I don't know it could take me ages to find a good example, but you can see that you know when it drops off extreme like this, it could be the sun coming over shading. but I do actually get a very with my old system. A very pronounced drop like that because any shading on one panel will pretty much drag down the entire string.

so I found that it dropped off very quickly. I won't now get that with the micro inverter. so you could claim that these micro inverters even though they're p You know you lose. Some days you'll lose power on the peaks.

You might actually gain those. You know that extra energy? Uh, over time by individually getting the panels if one panel gets shaded. If it gets bird crap on it or it gets whatever filthy dirty, uh, for some reason or gets hit by a meteorite, then uh, you know it's not going to drag down your entire system now. End phase.

Have actually given me some data on the Iq7 plus micro inverter here so You can see that the efficiencies here at 10 power level only 93 percent efficient. Uh, whereas the data sheet if you read the data sheet for the micro inverter, it just says 97 and that's it. It doesn't actually give you the parametric uh efficiency curves and this is where comes in the art of matching a particular micro inverter or applies to string inverters as well to your particular panels. The voltage output level the maximum current output level You know maximum how many cells they have and you know all that uh, sort of jazz.

So it can vary anywhere from 93 percent up to it looks like it goes right up. so only at the low end does it actually, uh, drop down there and a voltage nominal? We're talking 94 to 97 percent or something like that. So there's going to be variability in the efficiency of your inverter based on your input voltage which comes from your solar installation and the construction of the panels, the number of cells, and also then the technology used blah blah blah blah. It actually gets quite complicated when you want to try and match your micro inverters.

I mean, I, ideally if money is no object, if you've got a 5.1 kilowatt system like I do, you want 5.1 kilowatts at least of micro inverters so that you never clip and then you don't have to stay awake at night going. Oh geez, I'm losing one percent of my power today. That can keep you awake at night. So you can say that like in some ways, um like end phase have to release this sort of stuff because they don't.

Actually, if you've got 370 watt panels which is common as mud, they don't actually sell a matching micro inverter with that output power level. so they have to, you know, go to great lengths to explain to you even people in Australia here like I could upgrade to the Iq7a micro inverters which is their highest output micro inverter. But how much extra energy? not power? How much extra energy over time would I get out? Not much. and they're probably.

I don't know the price difference. They might be 10 15, 20 difference in price or something like that. And if they made a 370 watt micro inverter, well it could be. You know, higher price again.

And their their tests are showing that here in Sydney clipping is like 0.02 of the time and you know stuff like that which I I like probably don't doubt, sounds like it's in the order, sounds like it's in the ballpark, but I found that it would clip on 38 percent of days. but that's just days. But as I said like you've got to take each one of these like little individual peaks into account and stuff like that. So overall they could be right that you know if you calculate it all up um 0.02 percent of the days? I don't know.

Leave your thoughts down below. have you analyzed your system? Is it you know? Is it a D rated Uh system or overrated like? uh, this one has. It got like a Dc to Ac ratio greater than 100 because my existing system was smack on a hundred percent. And that's as I said.

The most common system here in Australia for string inverters is you put in a five kilowatt system. You get a five kilowatt inverter. That's just, you know how it was done. Um, but with micro inverters which are a more expensive solution because there's more of them per panel and you do get great advantages out of them in terms of like shading as I uh, showed you.

you know, like this panel over here could ordinarily bring down the entire system. There's a bird nesting on top of it or something, doing whatever, Then yeah, it's going to drag your whole system down, but it won't if you've got a micro inverter which will output optimal efficiency for each individual panel. And the whole argument with this overrating is the advantages of the micro inverters will actually gain you the extra output power to compensate for if they clip and loss. But not only is it a total calculation of energy over time, it's also a payback period as well because micro inverters are more expensive solution, but they gain extra percentage advantages.

but in this particular case, they might actually clip depending on which country and which in which city you're in. So you know, just because you're in Australia, it could be like in Tasmania or something. They don't get any sun do they? So when it comes down to it, there's not a huge amount in it. And this is why they are specified and based on their data, correctly specified a 295 watt max output micro inverter for my 370 watt panels.

But yeah, I've now got to sleep at night knowing that on Uh, 38 percent of days and nominally per year, it's clipping. How much energy I don't know. You could go like it's not a huge amount. As I said, like it's single digit percentage stuff.

But if you're paying 50 more for your micro inverters or whatever because you want just want the warm fuzzy that you're getting all the output power possible from your panel each and every day of the year, then well, how much does that impact your payback, calculation and stuff? It's it's complicated stuff. Anyway, that is micro inverter. Uh, when the micro inverter clip in D Rating: oversized panel over sizing? whatever you want to call it. It's actually quite complex business.

And let us know in the comments down below is this like common in your country? I believe this is like common as mud in Europe. Like everyone does this because they don't get that solar irradiance like we get in Australia. Look at it. Look.

look at it. Go. What a Bobby Dazzler December. Look at that.

Look at Australia for December. Look at that pink ass. Just like all day. it's just pink pink pink.

Anyway, I hope you found it interesting. If you did, please give it a big thumbs up. I was going to do it like a more polished version of this, but I you know with the white board and everything but talking dave head it'll do so. anyway.

I hopefully I'll have a video coming up, so stick around for that. Might go on my second channel. Maybe subscribe to Evblog2 on why I was getting negative here. It's not because they put the current, uh, transformers in backwards as some people speculated.

No, it's it's actually rather an interesting thing when you have a hybrid system like this with two different monitoring solutions with two different panels, but you want to combine the output power. This sort of negative stuff pretty much inevitable and how I solved it. I'll show you that in a future video. Catch you next time you.