[Solved] Maximizing PV Power: 18+5 Panels on Sloping Roof, Ceramic Tiles, Efficient Inverter Solutions

You need an inverter with two power measurement points.
In the morning, five panels reach their maximum power, and in the afternoon, the inverter switches to the second string of 18 panels.
I do not remember the minimum voltage for the inverter to start.

Don't be afraid of technical advisers - that's what they are for. Any designer, even acting on your behalf, will do exactly the same - he will contact technical advisors asking for help in selecting devices.

lodzik1990 wrote:

You need an inverter with two power measurement points.
In the morning, five panels reach their maximum power, and in the afternoon, the inverter switches to the second string of 18 panels.
I do not remember the minimum voltage for the inverter to start.

The minimum voltage for the inverter to start depends on the specific model. The inverter selection algorithm would be as follows:
1.selection of the model of PV panels - determination of their power, open circuit voltage and closed circuit current (for STC and NOCT conditions).
2. determination of the maximum power of the PV installation - most simply Ppv = nx Pmax
3.defining whether the inverter is to operate on a 1- or 3-phase installation.
4. determination of the maximum string voltage and its current (to remind: panels connected in series - open circuit voltages add up, current equal to the current of a single panel). In your case, respectively
DC voltage: String 1 - Voc1 = 5x Voc; String 2- Voc2 = 18x Voc (possibly Woc2 = 9x Voc if you connect two strings of 9 panels in parallel).
DC currents: String 1 - Isc1 = Isc; String 2 - Isc2 = Isc (or Isc2 = 2x Isc if you connect two strings of 9 panels in parallel). However, it is worth using longer chains, because even with less sunlight they will create more tension.
5. preliminary selection of the inverter based on the AC power and voltage and the number of MPP trackers
6. checking the voltages and currents of the DC side. If they fall within the limits specified by the manufacturer, then OK. At the same time, it is worth ensuring that the lower DC voltage value of the inverter is sufficiently low so that the inverters work even in conditions of lower sunlight
7.configuration of the system if something does not meet the boundary conditions (e.g. too low / high DC voltage of a single chain)

It is difficult to talk about specific solutions without knowing the exact situation and location / orientation of your installation, but I will present the above using the example of the first devices from the edge.
PV panel: Sharp 256 Wp / Mono: NQR256A
inverter: DELTA RPI H5A Flex 1ph (5kVA, 2MPP, DC IN: Vdc = 30 ... 600V, Idc = 11A / MPP)

Your configuration would look like this:
MPP1 = String1: Voc1max = 5x 32.5V = 162.5V; Isc1max = 9.95A; P1max = 1280W
MPP2 = String2: Voc2max = 18x 32.5V = 585.0V; Isc1max = 9.95A; P2max = 4608W
The input power of the second DC input has been exceeded, i.e. the inverter may not fully use the potential of the panels (of course, with good insolation parameters, but for NOCT conditions, the power is not exceeded).

This configuration will only work if both chains will produce energy simultaneously (i.e. the slopes are arranged in such a way that both are illuminated at the same time). Inverters have such a parameter as the permissible input unbalance, in this case it is the ratio of 4% / 96%.
Otherwise, consider using two inverters - one for a 5-panel string (DC inputs connected in parallel). The second is for connecting a chain of 18 panels (DC inputs connected in parallel).

For other panels and inverters, the optimal configuration may be different.

czesterw wrote:

I have a problem with achieving the appropriate power of the photovoltaic system.
Therefore, I have to place the panels on two slopes of the sloping roof
covered with ceramic tiles. I will put 18 panels on one slope,
on the other, only five. Can such a system work with some inverter?
Because I know from experience that many tz. traders trying to sell their product
my confidence in them is limited. I am asking for help from independent specialists.
Thank you in advance. Czesław

Solar Edge can handle it without any problems - I know because I have it

If you have a problem with the power unbalance of two MPPT inputs, you can try to configure 13 panels for one input, and two strings of 5 panels in parallel for the other.
Typically East-West panels can run in parallel without two MPPTs. This is due to the fact that for most panels the voltage at different levels of insolation at the point of maximum power is the same.

Just check the datasheet.

Look for an inverter with two MPPTs, do not listen to nonsense about LEDs, with inverters it does not work well and production on all panels will fail because the inverter will be stupid.
Most branded inverters have MPPT not "symmetrical", so you can connect, for example, 13 panels for the first string and the remaining 6 panels for the second string and everything will flicker as it should

czesterw wrote:

Pano
Gentlemen. You have presented all this nicely, but specifically whether my potential contractor's proposal will work. It proposes a Solar Edge SE5K inverter, 23 Q. CELLS 285W polycrystalline modules, 23 P300 optimizers. I want to put it on one chain. 18 panels will be on the S / W slope, 5 on the S / E slope. And so many of his suggestions. Would two strings improve system performance. I would like to thank all my colleagues and ask for more
a few remarks. Czesław

With this configuration, you are unlikely to find an inverter with two MPP, for example 23 panels are over 900V, 18 are over 700 and 5 is about 200, you would have to look for three MPP with the lowest voltage. take off.
Parallel connection of panels, especially those arranged on different slopes and with diode separation, will not do good either, MPP will not work as it should.

In my opinion, this Solar Edge also has these parameters a bit too low. 900V and the current of 8.5A and the Isc of the panels is 9.46A but here, ask how the contractor explains it, maybe it will never be achieved, but it is selected that the Isc should not exceed the maximum current of the inverter

I believe that an inverter with two independent MPPTs will be a better solution.
When it comes to the solutions of the Israelis and Solar Edge, it is difficult for me to speak, because I did not have it in my hands, the principle is that the inverter is without MPPT and must have optimaizers to work, it is definitely more expensive and whether it is worth your money, it would have to be uttered by someone who uses it at home.
For sure an inverter with two MPPT strings would do the trick, for example, SMA or Fornius, just check the MPPT start voltage for a given model, e.g. I have from 125V in SMA for a given string.

czesterw wrote:

Pano
Gentlemen. You have presented all this nicely, but specifically whether my potential contractor's proposal will work. It proposes a Solar Edge SE5K inverter, 23 Q. CELLS 285W polycrystalline modules, 23 P300 optimizers. I want to put it on one chain. 18 panels will be on the S / W slope, 5 on the S / E slope. And so many of his suggestions. Would two strings improve system performance. I would like to thank all my colleagues and ask for more
a few remarks. Czesław

Believe me, there is nothing better on the market than Solaredge. Don't listen to people that optimalizers are bad - just because they are an advantage in this system. You can even connect to string panels of different power, e.g. in two years you will add 360 W panels and replace only the optimizer with a larger one (PLN 200). What I can advise you is to take a larger inverter, e.g. 6.6 kW - the difference in price is almost rare because if you have panels on both sides, they will never work at full power at 100% at once. Because part of it will be 100% at noon and the other part at east or west. You have all panels in one string and each panel is treated independently by the inverter.
I have a 10 kW system on a 12.5 kW inverter -31 panels in one string scattered on both sides of the East and West and the system is spinning nice.
In addition, you have a preview of each panel in the application and you can see the production of each panel separately and potential defects too. If this happens, you immediately know which panel has failed and you are replacing it, and you are not looking in the string as with other inverters.

krissgut wrote:

Believe me, there is nothing better on the market than Solaredge.

Oh buddy, you are wrong, praise yours because you already have it, but in my experience it is the worst inverter that can be, and I am waiting for the optimizers to start raining. And one more thing is less efficient than the Fronius, SMA.

Added after 8 [minutes]:

In addition, a double number of connectors, which indicates a greater failure rate.

prose wrote:

krissgut wrote:

Believe me, there is nothing better on the market than Solaredge.

Oh buddy, you are wrong, praise yours because you already have it, but in my experience it is the worst inverter that can be, and I am waiting for the optimizers to start raining. And one more thing is less efficient than the Fronius, SMA.

Added after 8 [minutes]:

In addition, a double number of connectors, which indicates a greater failure rate.

I have 25 years of written warranty for optimalizers and 12 years for the inverter - fronius has 7 years - answer yourself as to the quality of the equipment

krissgut wrote:

prose wrote:

krissgut wrote:

Believe me, there is nothing better on the market than Solaredge.

Oh buddy, you are wrong, praise yours because you already have it, but in my experience it is the worst inverter that can be, and I am waiting for the optimizers to start raining. And one more thing is less efficient than the Fronius, SMA.

Added after 8 [minutes]:

In addition, a double number of connectors, which indicates a greater failure rate.

I have 25 years of written warranty for optimalizers and 12 years for the inverter - fronius has 7 years - answer yourself as to the quality of the equipment

This is no argument, all Chinese inverters now have a "25-year" warranty, after 5 years the company will disappear and look for wind in the field ...
I am also not convinced to solaredge, I knocked down 10 inverters and unfortunately, apart from SMA and let's say with Fronius, none of them is built "for years", I mean electronics and base components used for production.

krissgut wrote:

I have a 25-year written warranty on the optimalizers and a 12-year warranty on the inverter

And that's why you think he's the best? A colleague above wrote as it really is.

You can turn on the counter that is not listed and check if the consumption is increasing. Even if it grows, you will not go bankrupt during this time and the system will be pre-checked. Personally, I would go with two inverters in your case.

Power is the smallest problem, more serious is the open circuit voltage and Isc current, which, according to the calculations, exceed the permissible parameters of the inverter
Optimizers will not increase anything for you, at most they will reduce chain losses in the case of shading one or several panels

czesterw wrote:

I have access to the Solar Edge website https // monitoring.com / solaredge-web ..... as the so-called guest. You can see how a particular installation works. krissgut as a user has the option (correct me wrong) to observe each panel separately. I have the option to select each country and observe the installations installed there. As a user, I will probably be able to analyze my installation in more detail. krissgut, please describe in more detail how it works. I opted for one string 23 panels and a SE5K inverter.
It will never happen that my inverters simultaneously give more than 6.55 kWp and this inverter can take max. 6.75 kWp.

Added after 3 minutes:

P 300 optimizers increase the power of each panel by up to 20%.
Regards Czesław

You can see the production of each panel individually - I have 31 panels on two slopes of the roof and I can see 31 panels and the production of each of them. For example, one has a production of 0.25 kWh on one south roof and at the same time another one in the east has 0.15 kWh. Or in the morning it is exactly the opposite

krissgut wrote:

czesterw wrote:

I have access to the Solar Edge website https // monitoring.com / solaredge-web ..... as the so-called guest. You can see how a particular installation works. krissgut as a user has the option (correct me wrong) to observe each panel separately. I have the option to select each country and observe the installations installed there. As a user, I will probably be able to analyze my installation in more detail. krissgut, please describe in more detail how it works. I opted for one string 23 panels and a SE5K inverter.
It will never happen that my inverters simultaneously give more than 6.55 kWp and this inverter can take max. 6.75 kWp.

Added after 3 minutes:
P 300 optimizers increase the power of each panel by up to 20%.
Regards Czesław

The connector shows today's production - as you can see there are two roofs south and east - south 15 panels east 16 is green is an inverter - each panel shows the total production from today. I don't think there's anything else you need to explain.
You can see the production of each panel individually - I have 31 panels on two slopes of the roof and I can see 31 panels and the production of each of them. For example, one has a production of 0.25 kWh on one south roof and at the same time another one in the east has 0.15 kWh. Or in the morning it is exactly the opposite

czesterw wrote:

krissgut, I can see what it looks like and I think you can see even more. Write down how these 31 panels are connected and what the inverter is. Because it is very important. These considerations of theoreticians who advise and do not want to look at the manufacturers' website are worth little. And I'm risking a lot of money. The contractor is flashing like he can, he would like to get everything done, I would like to have his guarantee in writing. I am seriously considering withdrawing from the contract because time is passing quickly. Czesław

They are connected in one string, although my inverter itself has two strings, I have a 12.5 kW inverter and the panels are 10 kW, each has 320 W.
Of course, after entering a given panel, I can see each of them voltage, current and power at a given moment and a few other things. The application itself offers a lot of statistical possibilities. You can also connect a current consumption meter, then the app is developing seriously but I do not have this meter because I have a consumption application from Tauron that is enough for me and it is for free.

Added after 9 [minutes]:

krissgut wrote:

czesterw wrote:

krissgut, I can see what it looks like and I think you can see even more. Write down how these 31 panels are connected and what the inverter is. Because it is very important. These considerations of theoreticians who advise and do not want to look at the manufacturers' website are worth little. And I'm risking a lot of money. The contractor is flashing like he can, he would like to get everything done, I would like to have his guarantee in writing. I am seriously considering withdrawing from the contract because time is passing quickly. Czesław

They are connected in one string, although my inverter itself has two strings, I have a 12.5 kW inverter and the panels are 10 kW, each has 320 W.
Of course, after entering a given panel, I can see each of them voltage, current and power at a given moment and a few other things. The application itself offers a lot of statistical possibilities. You can also connect a current consumption meter, then the app is developing seriously but I do not have this meter because I have a consumption application from Tauron that is enough for me and it is for free.

I have 370 W optimizers

czesterw wrote:

krissgut. Write to me if you ever had 10kW produced at the same time. Obtaining from 32 panels which theoretically have a total of 10 KWp, some facing east and the other facing south is not possible. Unless they are all south facing and 100% efficient and under ideal conditions. In this situation, why do you need a 12.5 KWp inverter. As I read somewhere, the inverter works best with lower power than the sum of the panels. Unless you plan to expand the network or my assumptions are wrong. Who can add something on this subject, having experience. This not only applies to your type of inverter, did you also notice if what the optimizers' datasheets say works? They are supposed to increase the power of the panel up to 20% ..
Above, Fankykoval claims that it is possible to connect the installed photovoltaics to the grid for a while through an old, not yet mentioned meter. Is it safe, won't anything get mixed up? If so, before the specialists arrive with a new meter during the day, it would be possible to run on your energy in good conditions. But it would probably be a crime. I will definitely not try. Better to wait these 30 days and go legal.
Ps. I write on a Chinese tablet and sometimes I do not put tails on Polish letters, the system spelling option does not correct it. Sorry. Regards Czesław

I have installations from mid-March, so there were obviously not optimal conditions to reach 10 kW - so far I had the highest value of 8.2 kW, but it's only March so the sun is not at the optimal angle. Indeed, an east-south orientation will never acquire a momentary power greater than a south orientation. However, what is important for us is the production of the whole day, not instantaneous performance. In total, the production to the south and east and only to the south will give a similar value of kWh. For me in the appendix it is clearly visible - in the east the values are lower than in the south, but it all depends on the time of exposure of a given area to the pure sun. If the sky is cloudy in the afternoon, the sunrise will give more kWh if the sun is very bright in the morning.
I have 12.5 because I will be increasing the power soon.
When it comes to connecting to a one-way meter, nothing will go wrong for you. Everything is going normally, only that you have to pay for everything you produce. But technically everything works fine. For me, after connecting the system, for two hours everything was running on the old meter because the optimizers had to be loaded into the inverter - then there was an attempt to make sure everything works. The installer warned me that I had to pay for my production. - We shut down the inverter for a week. After a week of installing the bidirectional meter, everything is OK and we produce AC.

Is there any point in using SE + optimizers in a ground installation without possible shadows other than the shadow from passing clouds? It only comes to my mind: the possibility of monitoring individual panels + reducing the voltage to a safe value during service works.

Anyway, as I can see, if you do not have an installer account at https://www.monitoring.solaredge.com, you do not have access to many functionalities, e.g. alerts about incorrect installation operation, analytical data.