TomasCrespo

I know, but I do not know if very different amperage could be a problem, i.e. a string with 8.1 A and another string with 14A. Replacing the inverter is not an option (unless VM III die). Currently I have almost all the energy I need. It's a small off-grid country house and the loads are the pump of a swiming pool and an air conditioner (about 1000W each one), so I only need a bit more watts to keep the two loads working at the same time (and the battery loading). But once I redesigning the installation... I would like to get more power earlier in the morning and/or late in the afternoon (and cloudy days).

I am in Murcia, Spain. Not with 565W panels, but with 7x440W?

Thanks for the info. I know voltage of two strings must be very similar, but my question is about amperage. Could be significant differences in amperage of each parallel string? Any other option keeping old panels? What do you think about two strings with different orientation? Old string is south. I could create a new string facing southwest. They will never get 4000w, isn't it? Would be possible using a secondary MPPT with this setup (VM III with integrated MPPT and pylontech batteries)?

Sorry. Fixed.

Hi! I have a Voltronic Axpert VM III with a string of 8 Jinko panels (JKM330PP-72-V Vmp=37.8v Imp=8.74A) working for 6 years flawless. They get as high as 320v. My inversor has a label where is said that max FV is 4000w, and 500v (label attached) I want to increase the number of panels to have more energy before and after midday. The panels I can buy nowdays are: JAM54D41-LB 440W Vmp=32.47, Imp=13.55A JAM72S30 LR 565W Vmp=41.68v, Imp=13.56A My first though was make a second string with 7 (to get the most similar voltage) with 565W panels, but I will have very different intensity in each series, 8.74A vs 13.56A, which will generate in some hours of the day very much if 4000w (the max of the MPPT). Is there any problem on having two strings (parallel connected) with so different intensity? Is too much wattage for MPPT? Any experience overpaneling VM III? Will you recommend me any other combination? PS: I have a US5000 battery connected to VM III in Pylon mode, and probably I will add another US5000 soon

Thanks @Coulomb I have just upgraded remote panel to version 102.73 and now US3000C communicates perfectly with Voltronic VMIII in PLY mode, only with the second cable. I haven't updated main firmware (it keeps 20.65). Should I do it? I have always thought firmware update is a dangerous operation

Hi, I have two Pylontech US2000B and a Voltronic VMIII 5k for about 6 years. Voltronic is on mode PYL and communicates perfectly with the master Pylon via RS485, with a home made cable, this one: Now I have a new Pylontech US3000C battery module, whichi I must use as master, so connect Voltronic with it. I have read that I need a new cable for this battery, one like this: So I have made one. The results are: US3000C does not communicate with voltronic with any cable, neither old or new. I have tried with only US3000C module, without US2000 modules connected. I have tried changing cable ends, one end in Pylon and the other end in Voltronic, and upside down. US2000C communicates perfectly with old cable and with the new one! How is possible!? So... the only think I could do is... update the Voltronic firmware. Do you think this could be the problem??? or it has nothing to do? My actual firmware is: U1: 20.65 U2: 02.21 U3: 00.21 Do you think updating the Voltronic U2 firmware will allow communication? Is there any posibility of connecting a US2000B and a US3000C using the US2000B (I updated its firmware recently to v3.4) as master ? Thank you very much

Hi! I have a Voltronic VM III 5k with only one US2000 Pylontech module, so I set the Maximum charging current (parameter 02) to 20A. It has been perfectly working for one year, charging the battery in the mornings as far as 20A (about 950W). Now I have purchased another Pylontech module, US2000 too. I have connected both and they are working. My Voltronic VM II has Pylontech support and it informs that there is two modules in the LCD display. Also ICC inform of the two modules and its voltages, temp, ... So I proceed to change Maximum charging current parameter to 50A, but it come back to 20A after a few seconds. I have tried from the LCD display, from Watch Power bluetooth app, and from ICC. It looks like if it is applied for a few seconds, I can see my batteries charging at 1500w, but suddlenly come back to 950w. I double check the Maximum charging current parameter and it is at 20A again. It is like if Pylontech battery communicates with Inverter and replace the parameter Any similar experience? Any clue? The only idea that I have is changing the modules position, set the older module as master. Of course, my two US2000 batteries are different versions, because they were purchased with a year of difference. I have put the newest as master battery. Newer Pylontech US2000 part number: US2000NB02V00101 Date of production: 2020-31-15 Older Pylontech US2000 part number: ?¿ (I will update) Voltronic VM III firmware version: 20.25

Following Coloumb guess, you should disconnect your new battery, connect only your 2xUS2000 and charge them at 100%. Then disconnect your 2xUS2000 batteries and connect your 1xUS3000 battery and charge to 100%. Then connect all the batteries.

The only idea I have to avoid my batteries go off, is put a smart-switch (something like sonoff switches) in the cable between Pylon and inverter. That way I could "disconnect" the batteries to avoid they auto power off, and at sunrise "connect" again the batteries. I will do it in a near future. Yes. I use ICC + Home Assistant to control the instalation, so if the batteries are discharging too much I switch off almost everything.

Your are right. The thing is that I would preffer that inverter were off before batteries were off. I think if low cut-off voltage is reached inverter will not use the batteries and hence will switch itself off (because I don't have any source of energy). At sunrise, inverter will go on and recharge the batteries. Currently the low cut-off voltange (47v) is never reached. When batteries get below 10% they auto shut off, and their voltage is above 47v. This morning example, at 19% it is 48v. It will be great low cut-off parameter could be set at 48.5v or even better, set the low cut-off paramter by SoC

Congratulations, communication between your inverter and your Pylontech is definitively working However, one note about this. Firstly, I'm not totally sure about this, I had only one experience for the moment. The low cut-off voltage parameter has no sense with Li-ion batteries. It has sense for acid batteries. Your Pylontech battery will auto-switch off itself as protection measure, before 47v (max cut-off value in Inverter). I have that configuration, I have no grid and I have set low cut-off voltage set at 47v, but this winter with various cloudy days my system went off one night. However at sunrise my system switched on (because VMIII can work without batteries), but at sunset my system was off again. Next day same history, with the sun all working (pool pump, security cameras, internet connection...), with the night all off. I connect remotely to that installition during working days and only visit the installation on weekends. When I got there I realized that Pylontech batteries were off. I had to switch it on manually. Inverter can NOT even charge the batteries when they are off My guess are: If Pylon discharge deeply they auto switch-off, before inverter's low cut-off voltage been reached. Inverter can NOT charge the batteries even with a lot of sun until you switch on the batteries manually I suposse that if Inverter's low cut-off voltage were reached, the batteries will not auto-switch off, so, at sunrise they will be charged correctly.

I purchased an Axpert VM III and I received the original BMS cable, but it was not long enough, so I made the one in the pics with the same pinount. Its working perfectly for about one year. Of course I have configured the inverter in PYLON mode. If I disconnect the BMS cable the inverter beeps with error code 61 (I'm not really sure about the code number). If I connect again error disapears. This pic is the original cable I received:

Two images:

Wow! Great explication Coulomb, thanks! Not scared, I've done similar things with some machines, but in any case... too work! And even if I would have the JTAG... I dont have the password. For the moment, I will try that the seller give me a firmware update (I think he won't do it). As second option, I will flash the firmware you linked (20.59) and then test if my bad readings of pv input are corrected. It will be great if anybody had tested that firmware upgrade file first 😂 Lot of thanks

Anyway, I am interested in the process. I want to know the hardware and the process. Is there any info in web or could you make it public? I understand it is a difficult process, and I likely won't do it, but I am curious. By the way, I am an IT profesional and I have worked with electronic circuits other times. Thanks

Thanks for your reply. No way of backing up the actual firmware?

Great info! How do you know that file is 20.59? It only says version 1.0.0 How safe is updating firmware in this inverters? Could I brick it? Could I revert back to my previous version (backup first or download from anywhere)? I think I read something about VM III with mppt dip or freeze, and I don't have this problem, so I'm scared about the firmware update could give that problem. 😂

Hi! Coulomb, finally the seller has confirmed that they are having this problem (erroneous pv input readings) in their VM III and King models. They told me that are speaking with voltronic to find a solution (firmware update perhaps), but they are not very confidendt about getting the firmware update. It looks like other people its not having this problem with their King or VM III. I suppose because its another maker (Easus, Inverex...). Mine has no a specifc brand, but the seller is a trusted seller. I don´t think he sells clones. Could it be possible to update my unit with the firmware of another one? Currently my firmware is: U1 20 25 U2 01 21 U3 00 21

Inverter LCD screen values (pv input Watts) and ICC pvwatts are identical. So my problem is the same looking at ICC data or LCD screen data. My inverter show me less PV Watts than Load Watts 😱. Obviously this is impossible, because there is no mains and battery is apporting 0 Watts. @mazo78 Was this your problem? Was solved reflashing the unit?

I'm not sure how to check firmware version, but in ICC Inverter values I have: Main CPU: VERFW:00020.65

🙄 And what about Inverter's LCD screen? Should it show the right values?

Absolutely not. I have no AC in. Not grid neither generator. Totally offgrid. Could it be that the inverter wrongly reads pvwatts when the value is small (< 100 Watts) and it reads correctly when the value is bigger? I will post inverter's lcd screen pics when I get there

Yesterday daylight hours: As you can see, until 13 the battery is charging and the the figures have sense, pvwatts1 = batterybatts + loadwatts. However when the battery is fully charged I can´t understand the figures; pvwatts1 is not enough to feed the loads, and battery is not apporting anything. Detail from 13:00h:

Same graph, but with batterywatts in positive, to easy analyze. As far as I know, the Inverter autoconsume is not integrated in loadwatts, and it is about 50w. This is the small difference. I mean, the data is ok at night (batterywatts vs loadwatts) but not in the sunny hours (pvwatts1 vs loadwatts)