logo elektroda
logo elektroda
X
logo elektroda
Advanced Search
logo elektroda
Build faster with M5Stack »
Build faster with M5Stack » Stick • Unit • Cardputer
ADVERTISEMENT
Dostępna jest polska wersja

Czy wolisz polską wersję strony elektroda?

Nie, dziękuję Przekieruj mnie tam

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

---Ryba--- 489714 1705
Best answers

How reliable are Sofar inverters for an around-8 kW PV installation, and what problems or failures do users report?

Users report mostly acceptable results: one 6.6KTL-X had no problems for over a year, and another 8.8KTL-X owner said a firmware update to v2.20 removed the old clipping around 8 kW and let the inverter reach full peak power [#18112697] [#18662870] [#19158337] The most common problems in the thread were not outright inverter defects but installation/configuration mistakes: too many panels in one string or the wrong input mode caused DC overvoltage errors such as PvOVP, BusOPV or permanent fault, and the cure was to wire the strings correctly and keep each MPPT within its limits [#18322870] [#18323108] [#18359020] [#18360610] [#18699492] Another recurring issue was grid overvoltage: users saw ID01/Grid OVP shutdowns when mains voltage rose to about 253 V, and one case reached 280 V at the customer side; the inverter was behaving as designed in those cases [#18624602] [#18665849] A few users also mentioned Wi‑Fi/software quirks and awkward warranty handling, with the installer, seller, distributor and Sofar service bouncing responsibility between each other [#18306997] [#18322870] [#18323064] [#18331261] [#18772451] There was at least one real hardware failure report, where an 8.8KTL-X tripped AC overcurrent after about a month and then would not restart, so the unit had to go through warranty [#18771167]
Generated by the language model.
ADVERTISEMENT
Treść została przetłumaczona polish » english Zobacz oryginalną wersję tematu
Report a violation of the law
Reply | New topic
  • #1651 21124321
    xury
    Automation specialist  
    Get more specific. Which generation of Sofar? The G2 has a maximum current of 11A and the panels 13A. So if the panels are all on the same azimuth and it's G2 then it pays to give them on one string, but split into two MPPTs. At G3 too because of the voltage.
  • ADVERTISEMENT
  • #1652 21124470
    dark1309
    Level 6  
    SOFAR 5.5KTL-X G2. All panels are at the same azimuth
  • ADVERTISEMENT
  • #1653 21124491
    xury
    Automation specialist  
    So as I wrote. Do the whole thing on one, and at the inverter itself split into two MPPTs. Then, at maximum operation, the current will go equally 6.5A to both inputs.
    When operating the whole on one input, the maximum current from the string is 11A. That is a loss of about a kilowatt of power.
  • #1654 21125390
    dark1309
    Level 6  
    ok, I will

    Added after 35 [minutes]:

    In the inverter I have to change to INPUT MODE --> EQUAL?
  • #1656 21132874
    plm132
    Level 11  
    Hi. Patient Sofar 5.5 KTL-X, Selfa panels 14 pcs each 390 Wp (5.5 kWp) all facing south-west at 215 degrees, roof pitch 45°, and production reaches 4 kW, or 70% of installed power. Panels connected 7 at a time and pulled everything under the inverter and connected under 2 MPPT. I attach the photos. And now how to bite it to increase the production. Sofar Solar 5.5 KTL-X inverter label with technical specifications. Technical specifications of Selfa SV108M.2-390 solar panels. Screenshot of an app monitoring solar energy production, showing a power graph and other data. Interior of an electrical box with wiring and fuses. View of inverter connectors with PV cables and communication ports connected. .
  • #1657 21132958
    k_pec
    Level 34  
    plm132 wrote:
    And now how to bite it to increase production.
    .
    It looks like something is limiting (flattening out) your production around 4kW. Don't you have some kind of production limiting done - P(U) functions, Q(U) or something else?

    But that's a detail, because you still have a reduced production in relation to that number of kWp, because:[letter:6602667d3e]-When the panels are tilted at 45°, the panels produce about 12...15% less power than at the optimum tilt for June.

    - The panel's 390Wp output is, and yes it is, but for laboratory STC conditions. In the real world, by contrast, one is closer to NOCT conditions, i.e. 295Wp of power. You can take a safe 0.9 STC power for your estimates.Adding up, you have about twenty, twenty-something per cent legitimate power shortfall. The remaining shortfall is that flattening seen in the graph.
  • #1658 21133001
    faradek
    Level 22  
    >>21132874 Panels badly matched to inverter. The inverter has a maximum of 11A per single MPPT input and the panels at maximum power give a current of 12.69A. The inverter accepts 11A and hence the clipping on the graph.
    In my opinion, you should connect all the panels in series i.e. create one string and plug them in parallel under the two MPPTs.
  • #1659 21133043
    k_pec
    Level 34  
    plm132 wrote:
    Selfa panels 14 pcs. of 390 Wp (5.5 kWp) (...) Panels connected by 7 pcs. and pulled everything under the inverter and connected under 2 MPPT.

    And, just now, I forgot in the previous post.

    Seven panels in a string is about 200...215V voltage, and the voltage range for the tracer mppt for this inverter is 240...850V. And that's where the problem of power limitation could be.

    Independently - simply too low voltages for optimal mppt operation.
  • #1660 21133147
    Janusz_kk
    Level 39  
    faradek wrote:
    Panels badly matched to inverter. The inverter has a maximum of 11A per single MPPT input and the panels at maximum power give a current of 12.69A. The inverter accepts 11A and hence the clipping on the graph.
    In my opinion, you should connect all the panels in series i.e. create one string and plug them in parallel under two MPPT.

    Exactly, it was completely pointless to split them into 2 strings, one string and the inputs in parallel in the setup and you will be fine.
  • #1661 21133230
    plm132
    Level 11  
    >>21132958 Changing parameter 16 to unlimited, the current jumped above 11A and started cutting production, and where to look for Q
  • ADVERTISEMENT
  • #1662 21133304
    ICEMANIK
    Level 11  
    Hello, is such a sharp drop in the power of the installation on a warm cloudless day normal?
    Installation new, today the first cloudless and warm day about 30st.
    Sofar 4.4KTL-G3 inverter, 1string with a nominal power of 4kw (9x445W ENCOR EC445-450-10R-108FB)

    Graph showing changes in voltage and current in a photovoltaic installation throughout the day. Screenshot of data from the Sofar 4.4KTL-G3 inverter showing electricity generation parameters. Screenshot of data from the Sofar 4.4KTL-G3 inverter showing electricity generation parameters.
    Screenshot of inverter temperature data showing ambient temperature at 51°C and radiator temperature at 50°C.

    And also a data dump from the inverter:
    Attachments:
    • 2024-06-26 FalownikSS2ES144PCC011Raport (1).xlsx (78.37 KB) You must be logged in to download this attachment.
  • #1663 21133378
    Wawrzyniec
    Level 38  
    ICEMANIK wrote:
    Is such a sharp drop in the power of the installation on a warm cloudless day normal
    If the voltage dropped so sharply then the power must have dropped as well. Something obscured the sun and that was that.
  • #1664 21133492
    ICEMANIK
    Level 11  
    If I hadn't been at home I might have been, but I was today, and the cloudless sky was of limited power for that time. I should add that there is also nothing to obscure the sunshine
  • #1665 21133537
    plm132
    Level 11  
    Janusz_kk wrote:
    faradek wrote:
    Panels badly matched to inverter. The inverter has a maximum of 11A per single MPPT input and the panels at maximum power give a current of 12.69A. The inverter accepts 11A and hence the clipping on the graph.
    In my opinion, you should connect all the panels in series i.e. create one string and plug them in parallel under two MPPT.

    Exactly, it was completely pointless to split them into 2 strings, one string and the inputs in parallel in the setup and it will be fine.

    So do it like this? Diagram of connections for solar modules with the Fronius Symo 3.0-3-M to 8.2-3-M inverter.
  • #1666 21133555
    Janusz_kk
    Level 39  
    NO, it is still a parallel connection, you have to connect them in series in the box at the solar, that is, from string 1 the red one to the inverter and you connect the black one with the red one from the second string, the black one from the second string to the inverter. In the inverter, in the settings, you select not two separate strings but a parallel connection of the inputs and that's it.
  • #1667 21134199
    plm132
    Level 11  
    Janusz_kk wrote:
    NO, it's still a parallel connection, you have to connect them in series in the box at the solar panels, that is from string 1 the red to the inverter and you connect the black to the red from the other string, the black from the other to the inverter. In the inverter in the settings you select not two separate strings but a parallel connection of the inputs and that's it[/quote].
    And this is plugged into one MPPT?
    .
  • ADVERTISEMENT
  • #1668 21134466
    _ARo_
    Level 11  
    Hi, I have this problem that I don't understand.... I was using a 5.39 kW installation with a Solar Sofar 5.5 kW inverter from the south direction until 24 March this year. The inverter was pumping between 15 and 18 kW at peak according to the inverter and about 12-13 kW according to the Tauron meter. I extended the installation on 25 March, adding a second 2.7 kW circuit, changing nothing on the inverter. Production on a nice day was between 23 and 27 kW according to the inverter and about 22 - 24 kW according to Tauron.
    I decided to boost the inverter and on the internal microswitch I set it to 8.8 kW on 1.05. The inverter presented itself nicely as 8 kW and it was so nice to see it pumping at 8.4 kW.
    And this is where the problem begins.... The inverter shows a daily production of 45 - 50 kW in May (a beautiful increase in production) and Tauron registers a maximum of 25 kW. In June, the inverter is sucking up to 65 kW on a nice day, and Tauron still shows a maximum of 26 kW in the application.
    The autoconsumption issue with me has not changed, I don't know why Tauron has locked in at 25 kW. It looks as if just increasing the power of the inverter, apart from a temporary improvement in the user's wellbeing, does not change anything. The inverter shows a beautiful increase in production without affecting the readings that Tauron's meter registers.
    For the whole of May, the inverter boasts a production of 1.33 MW and Tauron shows 525 kW.
    Anyone have any idea what is wrong? Thanks in advance...
    I am also attaching a file with graphs
    Attachments:
    • LicznikiProdukcji.pdf (1.78 MB) You must be logged in to download this attachment.
  • #1669 21134499
    k_pec
    Level 34  
    _ARo_ wrote:
    Have any idea what is wrong? Thank you in advance...
    .
    After all, when you added the panels in March, your production increased accordingly, both on the inverter and on the Tauron meter, (1.5x), because at that time the panels were far from the rated max output of the panels and the inverter was cranking out.

    And by changing the settings in May, you have only changed the way the inverter displays the data - it normalizes the power not to 5.5kW but to 8kW - the production is still close to winter, because the inverter saturates the power from the panels in summer. This is why Tauron's meter shows as much as you actually produce.

    The way I see it.
  • #1670 21134605
    zdziseek
    Level 10  
    But a colleague changed a jumper in the middle. So as long as there is enough power in the panels, it should produce more than before the jumper change and give more to the grid, as long as it does not significantly increase the autoconsumption. As far as I know, with the G3 version it is no longer possible to increase the power with the jumper.
    It may also be that this is only an apparent change to 8.8, which is displayed as successful, but in fact produces the same amount as before.
  • #1672 21134619
    Janusz_kk
    Level 39  
    zdziseek wrote:
    It could also be that this is only an apparent change to 8.8, it appears to be successful, but produces de facto the same as before.
    .
    And this is probably the case, he is not the first one to have been run over by it, only the power coefficients for the conversion have changed, but the energy is still the same.
  • #1673 21135105
    JEDD
    Level 29  
    It has long been known that jumpers can be used to switch 4.4 and 5.5 to 6.6, and 8.8, 10 to 11.
  • #1674 21135396
    Janusz_kk
    Level 39  
    JEDD wrote:
    It has long been known that jumpers can be used to switch 4.4 and 5.5 to 6.6, and 8.8, 10 to 11.
    .
    It's just that the inverter must have a 'spare', if it doesn't then the effect is as _ARo_ describes at his place. The inverter falsifies the production data.
  • #1675 21152731
    zdziseek
    Level 10  
    Hello,
    My router at home has crashed. As a result, I have no PV production data either in the APK or on the WWW.
    Can some good soul explain to me step by step how now the WiFi logger I have hooked up to the Sofar 8.8 KTLX G3 connect to the new router? Thank you in advance
  • #1676 21152747
    radar1967
    Level 11  
    You don't have to do anything with the WiFi logger, just set the same WiFi network parameters on the new router as on the old one, i.e. WiFi name and password.
  • #1677 21191000
    lupa780125
    Level 11  
    >>21071913 Hi, I would also like to join the request for instructions on how to run P(U) on G3
  • #1678 21204405
    krzysk23
    Level 10  
    Hello, since Friday I have a new installation based on a SOFAR 5.5KTL-X G3 inverter. To the east (about 45 st) 6 panels and to the west (about 20 st) 8 Bauer 405 panels. I think the company has miscalculated something. I have a small production - 25-25 August (central Poland) after about 22.5 kW - it was sunny. This is my second installation- the first about 1 kWp smaller just to the west produced similarly. It seems to me that the voltages on the strings are too low, because in the east (6 panels) from 150-180 A, and in the west. (8 panels) around 180-220 A. What do you guys think about this? Maybe too big an inverter for this installation?
  • #1679 21204482
    ja_pizgam
    Level 10  
    @krzysk23 I on a 5.5KTL-X (first generation) have only 4.5kWp but south (15st) in 1 string, and the voltage range is 360-430V (I'm talking about the range where any current flows). You've probably confused the units a bit because A is amperage not voltage and you're unlikely to have that many amps ;) Generally that 20st to the west is quite a poor angle, there you should have above 40st due to the sun going down (as you have in the east). The voltage range is ok, more so check the current graph (since it was sunny the volume should be fairly straight and not jagged). I checked in your inverter's manual it's operating range starts at 140V but peaks at 240-850V.
  • #1680 21204497
    krzysk23
    Level 10  
    >>21204482 I obviously got the units wrong. As you write, the highest output is from 240V, and the 4.4 model is already from 190V. Should I influence the company to change me to a smaller inverter?
Reply | New topic
Report a violation of the law

Topic summary

✨ The discussion centers on experiences with Sofar inverters in approximately 8kW photovoltaic (PV) installations, focusing on technical issues, durability, and configuration challenges. Users report generally stable operation with models like Sofar 6.6KTL-X and 5.5KTL-X over extended periods, though some face connectivity problems, especially with Wi-Fi and software availability. A recurring technical problem involves input voltage exceeding the maximum allowed 600V DC for single-phase Sofar inverters (notably the 4KTLM-G2), causing errors such as PVOVP and BusOPV and inverter shutdowns. This is often due to too many PV panels connected in series on a single string, with 15 Q.CELLS Q.PEAK G4.1 305W panels sometimes exceeding voltage limits, especially in cold conditions where voltage rises. Solutions include splitting panels into two strings (e.g., 8 and 7 panels) connected to separate MPPT inputs, though some users report this does not fully resolve the issue. The maximum recommended panels per MPPT input is around 9 to avoid surpassing power and voltage limits. Users also discuss the need for three-phase inverters for larger installations above 7kW on a single phase due to grid operator restrictions. Software and firmware updates are sought after but not easily accessible, with some users lacking Polish language support. Comparisons with other brands like SMA and Fronius highlight Sofar's cost advantage but raise concerns about long-term reliability and service support, which is still developing in some regions. Network-related errors such as Grid OFP (over-frequency) have been reported, with troubleshooting involving network frequency checks and inverter restarts. Overall, Sofar inverters are considered a cost-effective option with some technical caveats related to system design, installation quality, and support infrastructure.
Generated by the language model.

FAQ

TL;DR: Field owners report 0–20 % daily energy loss when Sofar inverters trip on 253 V grid peaks; “set Country Code 12 for Poland and the problem goes away” [Elektroda, 3301, post #18624621] Why it matters: one menu setting often fixes most unexpected shutdowns without replacing hardware.

Quick Facts

• Max. DC input voltage 1000 V & MPPT window 240-850 V (Sofar 8.8KTL-X manual [Uri, #18921613]) • Recommended DC/AC oversize ratio ≤ 1.2 : 1 for KTL-X models [Elektroda, BikeBarian, post #18360391] • Country Code list: PL = 12, DE = 07, NL = 05 [Elektroda, Defence & 3301, post #18851696] • Typical firmware: V2.30 (increases AC limit from 4.0 kW to 4.4 kW on 4.4KTL-X) [Elektroda, prose, post #19034268] • Service e-mail: service.pl@sofarsolar.com; hotline +48 22 123 98 58 [Elektroda, AT PRO, post #18772451]

How reliable are Sofar inverters in everyday use?

Most 6–9 kW owners report trouble-free work for 1–3 years [Elektroda, iborkim, #18112697; Elekt...

Which menu code should I select for Polish grid parameters?

Use Country Code 12 (PL). It lifts the over-voltage trip to 253 V/10 min and 264 V/1 s, matching Polish NC-RFG limits [Elektroda, 3301, post #18851696] Selecting 07 (DE) raises the limit to 264 V but violates declaration of conformity.

My inverter shows ID01 ‘GridOFP’ and stops at noon—what now?

Measure L-N voltage; if it rises above 253 V, ask the DSO to lower tap settings or move PV to another phase. Until then, temporarily change Country Code to DE (07) or install a 230 → 220 V autotransformer [Elektroda, MariuszFEG, post #18623709]

What causes PvOVP / BusOPV errors on 4KTLM-G2 units?

Voc exceeds 600 V in cold sun. Split the 15-panel string into two of 8 + 7 or use a 3-phase inverter that accepts 1000 V DC [Elektroda, noja102, post #18323557]

Is the MPPT Scan function worth enabling?

Enable only when partial shading occurs; it rescans the IV curve at user-set intervals. Service says it "improves harvest under shade" but reduces output 1–2 % on clean arrays [Elektroda, 3301, post #18622124]

How do I update Sofar firmware myself?

  1. Copy the /firmware folder to the SD card.
  2. Insert card, choose Menu → 5.Software Update, enter password 0715.
  3. Wait until ‘Update DSP1 OK’, ‘DSP2 OK’, ‘FUSE OK’, then reboot [Elektroda, Grucha383, post #19029218]

The display boots for one second at dawn—is that harmful?

No. The capacitors charge when DC rises above 180 V, then discharge if current is < 20 mA; this soft-start repeats without affecting lifespan [Elektroda, rydzyk673, post #19035241]

Why does Solarman show 0.9 A per phase even at 0 W?

Firmware ≤ V2.30 reports reactive standby current as active. Real clamp-meter reading is ~0.2 A; ignore the dash-board figure until a patch arrives [Elektroda, wilk125, post #19038447]

Edge case: can the inverter fail after a breaker trip?

Yes—one 8.8KTL-X died after a 16 A AC breaker opened; display stayed dark despite correct DC voltage, requiring warranty swap [Elektroda, gotycki1, post #18771167]

How to auto-run a 1.5 kW boiler only on surplus PV?

Install a PR-energised relay with the inverter’s CT loop; set closure above 4.5 kW export so the heater engages only in excess production [Elektroda, 3301, post #19053070]
Generated by the language model.
ADVERTISEMENT