SOFAR 8kW PV Installation: Opinions, Durability, Failures & Experiences with Inverters

Will 15 + 10 panels be pulled by any single-phase inverter at all?
The current one (SOFAR 4KTLM-G2) only sometimes does not pull 15 pcs on one circuit, as my minimum 600 V is exceeded

iwostar wrote:

Will 15 + 10 panels be pulled by any single-phase inverter at all?
The current one (SOFAR 4KTLM-G2) only sometimes does not pull 15 pcs on one circuit, as my minimum 600 V is exceeded

The sofar of the ktlm and ktlm-g2 series are single-phase inverters with an input voltage of max. 600V and the problem in this case is not the power, but the voltage of these 15 series connected panels, because the power will be limited to the nominal one and there will be losses
And 1-phase inverters. they are also larger, e.g. 6 ktlm-g2 or 7.5 ktlm but these 15 panels connected in series also you will not connect to any of them, at most 12, in addition, the power allocation (until October this year) had to be greater than the inverter power, and the date is single phase up to 3.68 kW
So divide this current string and it will work, and adding a few panels and reporting such a modernization will not be successful with the current 4 kW inverter

Check Sunspec, because many Chinese are rejected because they do not meet the macroinstruction requirements, point 10, which indicates that the inverter is to be equipped with an RS485 port that supports the Sunspec communication protocol. If the inverter does not meet these requirements, it will not be connected to the installation. Enea requirements. Many inverters are rejected because they do not meet this requirement. Few inverters meet these requirements.

3301 wrote:

the problem in this case is not the power but the voltage of these 15 series connected panels,

How is the voltage to be a problem ?? .. since those in the STC 15 panels in a series give max 500V ... do you mean the open circuit voltage ?? .. but then the max is 600V.

witekem wrote:

Check out Sunspec, because many Chinese are rejected because they don't meet macroinstruction requirements

Oh, my friend is back and he is spamming all threads, he will explain to you in a moment which (Polish) inverter is the best and has the Sunspec protocol.
Only he did not read that this requirement applies to installations larger than 10kW

BikeBarian wrote:

3301 wrote:

the problem in this case is not the power but the voltage of these 15 series connected panels,

How is the voltage to be a problem ?? .. since those in the STC 15 panels in a series give max 500V ... do you mean the open circuit voltage ?? .. but then the max is 600V.

Exactly, and if you convert this voltage Voc to a temperature of -25 C, taking into account the temperature coefficient of the module, with 15 pcs, the string voltage may be above 700 V

3301 wrote:

BikeBarian wrote:

3301 wrote:

the problem in this case is not the power but the voltage of these 15 series connected panels,

How is the voltage to be a problem ?? .. since those in the STC 15 panels in a series give max 500V ... do you mean the open circuit voltage ?? .. but then the max is 600V.

Exactly, and if you convert this voltage Voc to a temperature of -25 C, taking into account the temperature coefficient of the module, with 15 pcs, the string voltage may be above 700 V

As we have already touched on this topic:
1) should the open-circuit voltage play no role here as the inverter always works under load, which means that Vmpp panels are also important here ??
2) If Vdc after take into account temperature coefficient will increase at -25oC by 5V, will the current also increase and thus the panel power ?? ... because if so, then we exceed the maximum allowable current per string ... and this regardless of the number of panels in the string.

If you have a MOSFET for 600V and you apply a higher voltage to it, it can get hurt regardless of the current. Of course, there are security features, but it is worth keeping an eye on it, especially since you can do several MPPTs or a parallel connection.

So the power of the panel should increase, but in winter the sunlight is rather suboptimal.

If these are values of the order of 0.3% / ° C, we are talking about 10-15%.

BikeBarian wrote:

3301 wrote:

BikeBarian wrote:

3301 wrote:

the problem in this case is not the power but the voltage of these 15 series connected panels,

How is the voltage to be a problem ?? .. since those in the STC 15 panels in a series give max 500V ... do you mean the open circuit voltage ?? .. but then the max is 600V.

Exactly, and if you convert this voltage Voc to a temperature of -25 C, taking into account the temperature coefficient of the module, with 15 pcs, the string voltage may be above 700 V

As we have already touched on this topic:
1) should the open-circuit voltage play no role here as the inverter always works under load, which means that Vmpp panels are also important here ??
2) If Vdc after take into account temperature coefficient will increase at -25oC by 5V, will the current also increase and thus the panel power ?? ... because if so, then we exceed the maximum allowable current per string ... and this regardless of the number of panels in the string.

ad.1. what guarantee that the string will always be under load?
ad.2. here it is the opposite, the temperature decreases, the current is also smaller

Sofar KTX-L series users - do you have Polish in your inverters?

It depends on some they have and some not

Mirek_Gab wrote:

Sofar KTX-L series users - do you have Polish in your inverters?

Not. on 8 running

May have depends on what distribution you buy

I only know that someone has it and can make it available.

noja102 wrote:

May have depends on what distribution you buy

Can you specify which distribution you want Polish from?

How much and for when and what do you want?

noja102 wrote:

How much and for when and what do you want?

. Buddy, if you have access, could you provide soft?

Write to the manufacturer, what is your upload program and how would you like a program to calculate the yield.

Thanks for the info, I have these two programs. Only software is missing

Nobody will give you the software, but the manufacturer can do it remotely if you are connected to the net. Installers rather press putty that there is no, you can not, etc. And the Chinese do not make any problems

Someone can say something more about how Sofar inverters work in the long run, because I am considering installing 2 units and I am still hesitating whether it is worth paying extra to SMA or Fronius?

It's better SMA, I have 9 years old 3 pcs and nothing is happening

I, too, have had SMA for several years, I have never had problems with them.

Well, I was most inclined to SMA, but the price encourages me to Sofar.
I have almost 3000 difference on the 8kW version, so it's a lot. Almost an extra year to return on investment.
In addition, I see that they are becoming more and more popular, so maybe the website will also improve?

I chose the Sofar (I have 5.5KTL-X). As the colleague above writes, the difference in price is almost a year longer return on investment. All devices are designed for a long service life and only time can verify this. By the way- and the Fronius also breaks

Mirek_Gab wrote:

I chose the Sofar (I have 5.5KTL-X). As the colleague above writes, the difference in price is almost a year longer return on investment. All devices are designed for a long service life and only time can verify this. By the way- and the Fronius also breaks

Have you had it long? Is it on the Polish menu?

..from two weeks. Unfortunately, without PL. But I'm looking for a software

Mirek_Gab wrote:

..from two weeks. Unfortunately, without PL. But I'm looking for a software

Do you want to play with changing the software? Did you assemble yourself or some company? Wifi works without a problem?

I did the whole installation myself. Wifi works - it's ok.

Mirek_Gab wrote:

I did the whole installation myself. Wifi works - it's ok.

How many have you gone out if you can know? What panels and structure?