Kurtbe

I believe that I have the same converter. And I am also relatively close to the sea. And my converter is actually placed outside, and temperatures here can rise up to 40°C. So far it's been performing very well since more than 3 years now...

Thank you Coulomb, U1 81.08 is the current firmware (But I knew that all along: I uploaded it myself). I have never updated with any patch so far, out of fear of getting it wrong and messing things up. The display runs on 22.25, both of which are probably the latest firmware versions for the MAX II. The converter has the 28066 Chip.

No need to apologize Coulomb. I am sure it boils down to me. 81.xx is for the Axpert Max II, as opposed to the 281.xx (which is NOT for the MAx II)? But i do not find a 81.xx... Concerning the 54.xx, I am clearly in the 22.xx zone (if we are talking display). I have no idea what you mean with "existing main (U1) firmware"... I guess I should apologize for being so ingnorant. Sorry... Kurt

Now you see, that is where I get confused immediately... You quote a number: 281.05: IS that for the MAX II, or for the MAX? ANd I suppose the more recent version would be 281.08? But again: for the MAX II, 8kW? Then you quote 54.xx. No idea What you are referring to. 2809 DSP... DISPLAY? So I will not start messing about until I know 100% sure that I will be using the correct firmware. I hope you understand that this is all "a matter of fact" to you, but I am a one-time customer for Axpert. I am far from stupid, But I am a trained psychologist. Not an engineer...😟 Thanks for understanding, Kurt

Hi Coulomb, so far I have tried nothing. Mainly because I have the impression that there IS no patch for the MAX II 8kW. That is mentioned nowhere as far as I vcan tell. Only MAX 8kW seems to be available... Greets, Kurt

Sorry, late answer

Hi jfmm, I have practically the same setup for the moment. 1 MPPT, 2700Wp. I am in the process of adding a West-East setup of 8X 600Wp. and connect those to the 2nd MPPT. This would allow to produce earlier in the morning and later in the evening, providing full batteries for the night and airco/heating and charging the car during the day. If you lose about 0.5 per day, then that is probably comparable to what I lose. Once I use MPPT 2, it will at least double. On a 10kW battery system, this is 10%, which is significant. It would be nice to be able to test the difference with a patched version, but indeed, the Max II is not in the list. As to your question, that is beyond my scope. But you can ask Coulomb, he will probably be able to help out. Good Luck, Kurt

Hi Coulomb, I am sure that you will become world-wide known soon now that AI is spreading the word! 😁 It is a pity that there are no patches out there for the Max II 8kW. Have you got an idea of the percentage of power that we lose because of that issue? Thanks, Kurt

Hi Jfmm, I never fully understood that issue either because it is rather technical. But for what I do understand it seems to be typical for the Axpert inverters. Their software seems to have been written in that way. That is why Coulomb has written so many 'alternative' software (Patches) which seems to deal with that issue. This is what AI says about it: What you are referring to is known in the solar community as the "PV sticky at 90V/100V" problem (also called the "90V bug"). While often confused with the premature float bug (which affects battery charging), this is a specific flaw in the MPPT algorithm of Voltronic inverters, particularly the Axpert MAX and MKS4 series. This is what AI says about it: What is happening? In the early morning or during low-light conditions, the MPPT tracker starts up but fails to find the optimal operating voltage (Vmp) of your solar panels. Instead of climbing to the panel's ideal voltage (e.g., 250V–300V), it remains "stuck" at a very low voltage, typically around 90V to 100V. Yield Loss: Because the inverter is operating far below the panels' efficiency point, you might only get 100W of power when you should be getting 800W or more. The "Kickstart" Effect: The bug often persists until a sudden change occurs, such as a cloud passing by or the user manually cycling the PV switch. This "shocks" the MPPT into performing a fresh scan and jumping to the correct higher voltage. Why does it happen? The firmware's MPPT logic is overly cautious. At low light, it stays at the lowest possible voltage to avoid "crashing" the string if the current drops. It essentially gets trapped in a "local minimum" and lacks the logic to regularly scan for a better power point at higher voltages. Solutions and Workarounds Patched Firmware: This is the only true fix. Community developers (notably "Coulomb" on the Power Forum) have released modified firmware for specific models that corrects this MPPT behavior. Hardware Workaround: Some users install a smart relay or contactor that automatically disconnects the PV input for 15 seconds if it detects the voltage is stuck between 80V and 100V with low current. This forces a reboot of the MPPT tracker. System Design: Increasing the number of panels in a string can sometimes pull the operating point further away from the "sticky" 100V zone, though this does not fix the underlying software error. SBU Priority: Changing the output source priority (e.g., to SBU mode) can occasionally trigger more frequent MPPT refreshes in certain models, though results vary. So maybe we should get some "lessons" in what this is exactly all about... 😉 I am sure that Coulomb can help us understand better. Greets, Kurt

Yes, it seem Yes, it seems to fit you well! What country are you based in? (I am in Spain with One system, and that is the one which I referred to.)

Yes, That is indeed an option and a solution. To me it is however too tech and would involve learning skills that seem somewhat steep. I am happy with the way it now runs: I have setup the %SOC on the Axpert itself, and the apps now allow me to read (but not change) the %SOC from the app. In this country the price of electricity is a complicated matter. I have therefore built a setup to adapt to that. I have installed a timer and a relay switch that is connected to the Axpert. If the batteries drop below a certain percentage SOC, then the relay will be activated and connect my system to the grid. But ONLY if the timer allows it. If this setup fails to provide power, and the Axpert shuts down, then an Automatic Transfer Switch will connect me to the grid. Thus, ensuring power at all times. If you are interested: Specific in my situation (whereby the house is 100% dependent on electricity, no other energy available): The grid price here is based on two principles: The amount of power that you might require at any one time (for example 40Amps), and the actual electricity that you consume divided in day/night zones. If you consume 0 Wh, but have a 10kW connection you would pay something in the region of 60€/month. If you have a 3kW connection, it would be something like 8€. The price of that connection is high during the day, much lower at night. The actual consummation of power is divided into 3 daily zones. The cheapest being from 00 to 08 am. Three 'middle' zones and 2 expensive zones. Weekends are cheapest zone throughout. This is how I have setup my system: The axpert will provide 8000 W (34A), which is plenty. And normally during the day the batteries combined with the solar power will provide that. Therefor during the day, I CAN connect to the grid but it will only provide 3kW. But this happens rarely. During the night I have a 5kW connection. In total I pay about 9€/month for this. In normal circumstances, I end up with nicely charged batteries at the end of the day. These will last me until the morning, usually still having 30%SOC. That makes up 80 to 85% of all days: no grid, only sun and batteries. But the sun does not shine every day... So, from time to time, I need backup from the grid. Clouded days (mostly in winter) make up the colder days. Meaning that in the evening I might require some heating (heatpump will consume about 2,5 to 3 kWh). If I monitor that so as to keep the batteries above 10% before midnight, then at that moment the relay will open and send power to the batteries. I allow 2500 to flow to the batteries (with the app), and if the weather forecast predicts subsequent cloudy day, I will let an appliance run at the same time (Dishwasher, laundry, filter pumps, etc.). When the SOC reaches 60%, charging stops. This allows for heating in the morning if needed. If during the day, the batteries do not charge (no sun), then the timer will allow to charge between 2 and 6 pm (the middle-priced zone). This will again provide 60% SOC at 6 pm (in theory), If I cook before 6, then the 60% will normally suffice for the rest of the evening. If there is NO power anymore from the batteries or the sun, then the ATM will connect me to the grid at any one time (limiting me to 2.5 kWh during daytime and 5 during the night). The combination of all this results in few connections to the grid, but when I do, it is almost always during nighttime, allowing for sturdy charging of the batteries, but at a very cheap rate. exceptionally I will connect to the grid during daytime, but at a slightly higher price. There are only three downsides to this setup: 1: When the Axpert shuts down before midnight, it needs to be reset manually, or it will not charge during the night (it will however start itself up again when it 'reads' solar power from the panels in the morning). And 2: when the grid connects during the day, the batteries will hardly charge at all. As long as the Axpert receives the slightest bit of sun, it will hardly allow the batteries to charge but rather provide the energy to whatever one consumes in the house. It will not send its maximum power to the batteries (because of the setting: Solar, Batt, Utility). and finally, 3: whenever connected to the grid, there is little power available, so heavy consumers cannot be used simultaneously. If I could find a solution for problem 1 (Axpert starting up when if 'sees' grid power) and 2 (allowing fast charging during sunshine), to me, it would then be a perfect system. SO, admittedly this is not a perfect system. But it works, and with some monitoring in winter, it provides for a very cheap bill and a huge saving on CO² production. My bill varies between 12€ (just for the connection) to 55 something in a dark and cold month. (This winter being December: 203kW, of which 180 at cheap rate 0.17€. Including electrically heating up the solar boiler twice). Let me know how the Solar Assistant works out! Regards, Kurt

Hi Jfmm. this is EXACTLY what you can expect, and what I tried to explain before. The Axpert itself (via its own physical panel, WILL act according to SOC%, but ANY app or even Dessmonitor (via a browser) WILL continue to report in Voltage. BUT: your Inverter WILL act according to the settings you made. One can only hope that the apps or Dessmonitor will adapt shortly. Kind regards, Kurt

Hi Jfmm and coulomb, When setting the SOC% values (in my case) it needs to be done on the ACTUAL converter (using the physical panel on the inverter) It cannot be done via any app. After that, the inverter WILL react accordingly. HOWEVER: NONE of the existing Apps (as far as I know) will REPORT in SOC%. WatchPower, Energy-Mate and Dessmonitor (via a browser) Will ALL still report in Voltage terms. My guess is that Voltronic has changed from Voltage to SOC%, But that tha actual apps have NOT adapted nor upgraded.

to Jfmm: If you are using windows 11 for the update you might need a driver in order for the upload cable to connect properly (depending on the chip version of the computer). If you experience any problem: feel free to contact me. Kurt.

Hi jfmm. If you cannot find the Firmware files online: I can send them to you. Greetings, Kurt

On 2025/12/17 at 11:29 AM, rabihhatem said: the company that sold me the inverter is long gone ... so that is a dead end for me.: Try and find another Voltronic reseller in your country...

You're welcome. But I am afraid that only Coulomb will be able to provide the answer on the firmware versions. Good Luck.

Because of the difference between the TWIN an not TWIN version, I run on quite different frimware. 22.25 for the display and 81.08 for the inverter (So nothing like the 54.xx that you need.). Therefor this software is not applicable to your system. I can however confirm that this version does allow SOC% settings. But only via the display of the converter itself. APPS like Watch Power, Energy Mate and Dessmonitor via a browser still will NOT work with SOC%. As an example: these are my settings: in numeric order 1 SBU= Solar, Batt, Utility (mains) 2 80: defined by Pylontech 5000. I put 50 (2400W) 3 input voltage range: UPS (tranfer =15ms, APL =20ms) 5 battery type: (PYL) 'USE' allows '13' to go below 51V 6 restart enable 7 restart enable 9 output frequency: 50 10 output voltage: 230 11 Maximum charge from grid (utility): 30Ax48V=1440W 12 sets dry-contact @30% SOC=>grid 13 sets dry-contact @50% SOC=>battery 16 Source: SNU (solar&grid) but grid only if timer 'on'. 18 alarm control: on 19 return to default screen: on 20 backlight control: on 22 beeps if source is cut off: on 23 Bypass enable=return to grid @ batt. overload 25 record faults: enable 26 bulk charging Volt: 53,2V, (by Pylontech)better=52,4 27 floating charge Volt: 53,2V (by Pylontech) Better=52,4 28 AC output mode: SIG (single phase) 29 Shut down @10% SOC '05'=PYL 47,9V when 5=USE 30-36 Not needed for Li-Ion Batteries 37 not reset data 41 Max. batt. Discharge= dds (disable) 82 12V output on/off 83 erase data log 84 data log interval: 10=6/hr=144/d=10 days 20=3/hr=72/d=20 days 30=2/hr=48/d=30 days 60=1/hr=24/d=60 days 85-89 Time and date 91-98 LED's. 96:orange, 97:blu, 98: green 99 Timer for output source priority 100 Timer charge source: solar 1st (CSO):00-00,Solar+grid (SNU):00-00,only solar (OSO):00-00

I am willing to help, but if I read correctly this is about an Axpert MAX II TWIN 8KW, I own a Axpert MAX II (not twin) 8kW, so I guess I am of little use to you...

Thank you. Very kind.

Thank you for the advice, but I am afraid that taht is a little out of my leage. Kind regards, Kurt

hi Alexisis, IF we are talking Max II, 8oooW, then the latest firmware is 81.08 and 22.25 for the display. I have both official versions if you want them. They also allow to programs 12 & 13 in SOC%. However the apps do not seem to follow this. Is there anyone who knows of an App that will allow to change the settings in SOC% instead of Voltage? (Not WatchPower, not Energy-Mate, nor Dessminitor can do it.) Greetings, Kurt

Get well soon! Kurt

Thank you Coulomb for your answer. Yes, the inverter now shows that it runs with 81.08 and 22.25... But still, all is in Voltage rather than SoC%. 22.25 was the latest version the vendor has... I have informed him too, but so far no reply. I guess I will wait a few days and see what happens. PS: Hope you got your coffees. Kind Regards, Kurt