Hello everyone,

I have been using a small 3.6 kW hybrid inverter without any issues until now. I recently decided to expand my system and purchased a 10.2 kW (dual output) inverter from Alibaba, which appears to be unbranded. I connected approximately 6 kW of solar panels and a 105 Ah 16S Lifepo4 battery that I built myself.

However, I am encountering a problem where, when the energy demand from the solar panels rapidly increases, the panels get disconnected and the energy from the battery is used instead. If I'm connected to the grid, it will draw a lot of energy from the grid. The panels will then slowly reconnect and start providing energy again.

This issue only manifests itself when the energy required from the panels suddenly increases. It doesn't occur when I'm already using a lot of energy from the panels.

The problem becomes more severe when I'm off-grid and the battery is low, as it interrupts the output even though there may be 5 kW available from the panels. I have read feedback from other users who have purchased the same inverter, and they have all reported the same problem.

Do you think this can be resolved? Is it a software issue that could be fixed with a firmware update?

I have attached a video demonstrating the problem.

Hello, you can't see anything from the video, but I can tell you that the inverters don't have 10.2 kw, I think they are 7.2-8.2 kw, 

Aceasta este placa de control și folosește TMS320F28062PZT

Edited February 11, 20233 yr by valyh

I reloaded the video at 2x speed to reduce its file size to less than 3MB for attachment purposes. I also captured a photo of the label. Today, I significantly increased the output, and the issue does not appear to persist. It seems to be caused by either a poorly calibrated or malfunctioning current or temperature sensor.

No luck, I am attaching the compressed video in .zip format

20230208_151058.zip

Edited February 10, 20233 yr by Talino8

Yes, exactly as I experienced with them, they say that the inverter is 10.2kw, but it is 7.2 - 8.2kw, only colleagues who have the same motherboard, the model is 156-050113-00G(B) can tell which inverters is still used

On 2023/02/11 at 1:47 AM, valyh said:

This is the board of control board and use TMS320F28062PZ1

It looks very Axpert VM-ish. Almost certainly a clone / work-alike. The dual output back in mid 2022 [ edit: I think I misinterpreted the date code in the serial number ] is interesting; Voltronic are producing such models just recently. Maybe Voltronic are trying to play catch-up to a clone maker. [ Edit: Oops! I didn't notice that this is an on-grid model (true hybrid). So two outputs is standard for these (essential and non-essential/grid output). ]

Inside it looks quite Axpert-like. [ Edit: So it's likely some sort of Infinisolar V model or clone thereof; these are very Axpert like. ]

Edited March 6, 20233 yr by Coulomb
As indicated in [ square brackets ] .

But they have a single mppt of 27A, I don't know if it will have the necessary power to produce at least 8 Kw.

I have two models with the same parameters, but the blue one does exactly the same as my colleague's, it disconnects mppt, I took the control board from the white one and put one on the blue one and it works normally, I think the software is to blame, I mention that the softwares are different

It looks like him, and I believe it's around 8Kw, I really don't understand the meaning of dual output, in fact, I haven't used the second output yet. In the next few days I will post pictures of the interior, since on Alibaba the warranty is zero.

However, it seems that with a very charged battery problem doesn't arise. But I have to continue to test. Apparently, the inverter has an absorption of 300-400W on load, which must be immediately found in the battery, otherwise, it disconnects the PV.

We will update in the next few days.

Here are the photos as I had anticipated. Yes, it is him. I still haven't figured out if it's a clone or a Voltronic. Anyway, the error is no longer manifesting since I keep the battery charged. What I seem to understand is that it needs about 400W of surge power when asked for a rapid increase of output that it doesn't get from the PV, but takes this energy from battery or from electric grid. That's why I put it completely off-grid, otherwise it consumes a lot of energy from the grid. I manage the output with an ATS that switches between the inverter and the electrical grid.

One thing is for sure: it can't be used without a battery.

Finally, I wanted to ask you a question: in your opinion, is it possible to have different voltages in the two PV inputs? I have 8 new 400W PV with a Voc of 38V 14A available in series, and in the other input I put two series of 8 PV (for a total of 16 PV) at 230W and a VOC of 37V 7A. However, I have a lot of 230W panels. Can I, for example, connect 12 230W PV in parallel and connect them to the second line? So I would have 301V (the 8 new PV) at one input, and 444V at the other. Can this be done in your opinion?

13 hours ago, Talino8 said:

That's why I put it completely off-grid, otherwise it consumes a lot of energy from the grid.

I just noticed that yours is an on-grid model; it mentions feed-in on the sticker on the side. So it's definitely not an Axpert clone, but it could well be an Infinisolar clone (same manufacturer makes both). I added this to my earlier comment: "[ Edit: Oops! I didn't notice that this is an on-grid model (true hybrid). So two outputs is standard for these (essential and non-essential/grid output). ]"

13 hours ago, Talino8 said:

in your opinion, is it possible to have different voltages in the two PV inputs?

It depends on whether there are two independent MPPTs, or if you just have two input connector sets wired internally in parallel. If they are independent, then yes you can have them with totally different voltages and power levels. If they are paralleled, then the voltages have to match to within 5%, and it's best if the strings contain much the same panels in terms of Imp. Yours are nearly 50% different, so that's out of the question (if the PV inputs are paralleled).

I only see one pair of red/black lightly twisted heavy wires heading off to what I expect is a boost inductor, so my guess is that you only have one MPPT, so those inputs are probably paralleled.

Edit: Also, the sticker doesn't mention two MPPTs inputs.

Edited February 14, 20233 yr by Coulomb

Thanks, yes I really think it's a single mppt 😕 Yes, it's an ongrid inverter with the possibility of disabling the transfer to the grid

However it cannot be defined as a hybrid inverter because in my opinion it absorbs too much energy from the electricity grid.

On 2023/02/14 at 10:31 AM, Talino8 said:

Thanks, yes I really think it's a single mppt 😕 Yes, it's an ongrid inverter with the possibility of disabling the transfer to the grid

However it cannot be defined as a hybrid inverter because in my opinion it absorbs too much energy from the electricity grid.

How is this inverter? Have u solved the problems?

I bought victor max inverter (10.2kw) in december. I got someone to do installation for me, after installation he connected communication cable from inverter comm port to battery CAN Bus port. inverter worked for about 20 minutes and smoke came out of the inverter and the inverter switched off. Opened the inverter and found the card with comm port burned. i contacted the seller and new card was send to me, i connected the new card but inverter still failed to switch ON. The seller then send me a new motherboard, i replaced the motherboard and the inverter switch ON and worked well without without communication with the battery (Open loop communication). I wanted to do a closed loop communication between the battery and the inverter, contacted the seller for assistance but received none. Tried to establish communication and card with COMM port burned once again. I have to get a new card but i need assistance,  Anyone who knows how to establish communication between victor max IP21 and lithium battery (51.2V)

52 minutes ago, Phuti said:

I bought victor max inverter (10.2kw) in december. I got someone to do installation for me, after installation he connected communication cable from inverter comm port to battery CAN Bus port. inverter worked for about 20 minutes and smoke came out of the inverter and the inverter switched off. Opened the inverter and found the card with comm port burned. i contacted the seller and new card was send to me, i connected the new card but inverter still failed to switch ON. The seller then send me a new motherboard, i replaced the motherboard and the inverter switch ON and worked well without without communication with the battery (Open loop communication). I wanted to do a closed loop communication between the battery and the inverter, contacted the seller for assistance but received none. Tried to establish communication and card with COMM port burned once again. I have to get a new card but i need assistance,  Anyone who knows how to establish communication between victor max IP21 and lithium battery (51.2V)

 

Phuti, according to Victor Max inverter manual COM port is basically RS232 port (see manual page 5).

Did you try to connect with RS232 port from battery? not sure how will react.

Regarding disconnecting the mmpt, I have the same issue, but somehow I managed to solve it. I think it's software, and related to parameters 37 and 38.

Not sure what does parameter 38 when parameter 37 it's OFF or in Hybrid. Maybe someone can explain.

Thank you!

Hi Phut, please tell me what software version you have and what COM port you have on the inverter, because you have a voltage of - 12 V on the RS232 port for the wifi module, so I also burned an rs232 - usb converter.

On 2023/03/03 at 6:52 PM, valyh said:

Hi Phut, please tell me what software version you have and what COM port you have on the inverter, because you have a voltage of - 12 V on the RS232 port for the wifi module, so I also burned an rs232 - usb converter.

Hello Valyh. I'm not sure what software version is running on this inverter. i contacted the manufacture and they also told me that i must use RS232 but now the battery manufacture says you can only communicate with the battery via CAN port, so i'm confused now. I must now buy a communication cable (RJ45 to RJ23) not even sure such cable exist. I will be afraid to try this since you saying you also burned the USB converter while using RS232 port. My battery has 4 ports available( CAN, RS232 and Two RS485). 

On 2023/03/03 at 10:40 AM, Silviu TM said:

Phuti, according to Victor Max inverter manual COM port is basically RS232 port (see manual page 5).

Did you try to connect with RS232 port from battery? not sure how will react.

Regarding disconnecting the mmpt, I have the same issue, but somehow I managed to solve it. I think it's software, and related to parameters 37 and 38.

Not sure what does parameter 38 when parameter 37 it's OFF or in Hybrid. Maybe someone can explain.

Thank you!

I contacted the Manufacture and they said i must use RS232 port from the inverter to the battery. I then contacted the battery supplier and they said communication on their battery can only be established via CAN port and not RS232. so i'm a bit confused now while waiting for the new RS232 USB converter for the inverter 

Hi,

 

BTW, what android app are you using to monitor the solar production, battery status and this kind of stuff? In my SmartEss app, I'm not able to see monthy/yearly and total energy, only some real time values.

 

Thank you!

Sorry for the delay!

@Puti: You made a big mistake and damaged the inverter by connecting the battery to the WIFI port. Fortunately, you found an incompetent seller, so the breakage is still covered under warranty. The battery must not be connected to that port! 

The wifi app is poor. It does not provide the daily kWh produced, it does not provide many essential parameters. The graphs are only daily, the others don't work.

 

@Silviu TM Regarding the PV disconnect issue, I haven't found a permanent solution yet. The problem usually occurs on cloudy days, but rarely on sunny days. To mitigate the issue, I added an external MPPT to always charge my battery. Although it's hard to find a 10Kw inverter at such a good price, this solution was lucky.

How did you set the parameters 37 and 38? They relate to the energy transfer to the national grid. I disabled them as I have no contract with national grid, but actually I'm totally off-grid, no connection to the network, so if it's a software bug I could set parameter 37 to Hyd

Edited March 8, 20233 yr by Talino8

1 hour ago, Talino8 said:

Sorry for the delay!

@Puti: You made a big mistake and damaged the inverter by connecting the battery to the WIFI port. Fortunately, you found an incompetent seller, so the breakage is still covered under warranty. The battery must not be connected to that port! 

The wifi app is poor. It does not provide the daily kWh produced, it does not provide many essential parameters. The graphs are only daily, the others don't work.

 

@Silviu TM Regarding the PV disconnect issue, I haven't found a permanent solution yet. The problem usually occurs on cloudy days, but rarely on sunny days. To mitigate the issue, I added an external MPPT to always charge my battery. Although it's hard to find a 10Kw inverter at such a good price, this solution was lucky.

How did you set the parameters 37 and 38? They relate to the energy transfer to the national grid. I disabled them as I have no contract with national grid, but actually I'm totally off-grid, no connection to the network, so if it's a software bug I could set parameter 37 to Hyd

@Talino8Thank You. Does this mean this inverter works only on open loop communication with the battery since there is only one port (COMM)?. Luckily the warranty covered everything, the seller is going to send me new card and i'm advised to use RS232 on the battery instead of CAN port

@Phuti sorry for asking, but who is this seller? It seems very correct and helpful if he sends you another card again. The next one I might buy from him.

Also, don't you experience the PV disconnection problem?

@Talino8I bought it from Curley Wei Via Alibaba. unfortunately i dont have Panels yet, only planning to add them soon.