Coulomb

These constants are in a function that ensures that the values in EEPROM are within expected limits. If outside these limits, values are set to defaults. So this will have no effect most of the time, yet you will need to change these to expand the limits. Yes. The display firmware won't let you enter settings values that it considers to be beyond limits. Displaying the values for setting 13 properly will require an out-of-flow patch, i.e. a jump to new code to process the extra values. I have done such things, but it's a lot easier with some Python code that a colleague and I developed some years ago. It might be easier for you to use monitoring software to alter the settings; do you use such now? Will it allow other values? It might be that you need to change the response to certain commands; from memory, that's how WatchPower works. A command like QMCHGCR returns the valid range of values for the maximum charge current setting, and WatchPower makes sure that the parameter to a command to set the present maximum charge current is one of the allowed values. See a protocol manual for details. Getting late here; more later.

Sorry for the late reply. As you have seen, yes. But there are limits related to hardware, obviously. 72.xx is a known Axpert Max E '28066 non-Twin firmware series. 72.03 is quite early, from 2022, so I would say not related to newer models. They are all over the place, unfortunately. A quick look at x12.15 indicates that it does not check the parameters to PBFT (Put Battery FloaT voltage) and PBCV (Put battery CV voltage) commands. So it may be possible to leave the U2 firmware untouched, though I suspect that you'll run into trouble somewhere. Yes, I have 72.03, but you may as well go directly to 73.08, which is a more recent version of the same firmware. I don't have 112.15 (I do have 12.15, which is functionally the same, but it won't work for technical reasons). The closest I have is 112.19, but you may as well go to a more recent version like 12.28. (12.xx with xx > about 20 will safely replace 112.xx; they dropped the leading 1 at that point).

It's probably an IRF640, but any TO-220 MOSFET with similar specifications should work. Here is a 24V clone's power supply schematic in case it helps:

This seems to be a Voltronic Axpert work-a-like. The second photo seems to be of the main power supply. The area around the UC3845 IC doesn't look electrically burned, so much as someone was ham fisted with flux and a reflow tool. In other words, it looks like someone has repaired this section before. An Axpert main power supply schematic such as the one in the below post can serve as a guide, but of course the parts designators (e.g. D34) will be different.

Re-sent. It seems to have worked this time.

Sorry, I can't help with rolling back, but I have sent a Private Message with two desperation messages to try. I hope it worked; I got the endless spinning wheel after I sent it, and don't seem to be able to find sent messages to check it.

Please tell us the brand and model of the 10kW inverter.

This appears to be an EASun with modified Voltronic firmware. I wonder if it's legal (e.g. EASun gets Voltronic source code under license), or it's illegal (they reverse engineered the Voltronic firmware and use without permission). My guess is the former. You may find it hard to find monitoring software that will address all the extended settings.

I'd say that this is your main problem. If you can't find a setting that keeps communications up to the BMS, then resort to setting USEr. That means that the BMS won't be able to intervene to save a weak cell that goes over- or under-voltage, but at least it should work. Yes, definitely change this setting higher. I suggest 150A, for C/2. Your battery should be able to sustain this continuously, though perhaps find the actual recommendation from the battery documentation. If none of this helps with the PV power, then unless your inverter is made later than December 2025, I'd say give firmware 75.85 or one of the x75.85 patched firmwares a try. Unfortunately, you will have no way back to 75.08, or any other suitable 75.xx firmware, unless one happens to turn up in future.

Usually there is a small sticker over one of the screws holding the front cover on. It will have a year and one month blacked out. For example, the one below has a manufacture date some time in May 2018: That depends. If your manufacture date is considerably later (say 6 months or more) than the firmware, then you might decide it's not worth regressing that far. Alas, that information has not been published for many years, ever since the appearance of the clones. The best you can hope for is a vague clue in the file name of the firmware update file, e.g. "fixes fan speed at low power". But we don't have a firmware update file for 75.08 (except for one that is for an Axpert King rack mounted; a totally different firmware with confusingly the same version number).

Just for completeness; I don't expect this to be any better for @almusarrej . This is main (U1) factory firmware version 43.35 for the Axpert VM II Premium 3kW or 2.5kW '28062 non-Twin. Do not use with any other model or version. Use at your own risk. The hex file is dated 24/08/2023. This firmware uses a different EEprom layout to firmware versions 43.0x and 43.20, but the same as versions 43.22 through 43.29. Firmware upload instructions for models with a removable display. This firmware processes the QDOP command, so with suitably recent display firmware, it should support SoC% for settings 12,13, and 29 when connected to a suitable battery's BMS. The RAR file password is "flash" without the quotes. VMII_Premium_2K5_3K_MAIN_Reflash_Ver 43.35 pw flash.rar

OK, I'm now thinking that you want one of the firmwares in the range of 43.05 through 43.20 (inclusive, but possibly excluding 43.07 since it has a 3.6kW variant where the others have a 2kW variant). 43.20 was made only 5 months after your inverter was made, so it has the best chance to be compatible. Sorry for the delay in publishing this. This is main (U1) factory firmware version 43.20 for the Axpert VM II Premium 3kW or 2.5kW '28062 non-Twin. Do not use with any other model or version. Use at your own risk. The hex file is dated 13/09/2023. Firmware upload instructions for models with a removable display. This firmware processes the QDOP command, so with suitably recent display firmware, it should support SoC% for settings 12,13, and 29 when connected to a suitable battery's BMS. The RAR file password is "flash" without the quotes. VMII_Premium_2K5_3K_MAIN_Reflash_Ver43.20 pw flash.rar

That appears to be a work-alike of an Axpert Max II 11kW Twin, but with a non-standard display (the display is standard for smaller models). So commonly available Voltronic firmware is unlikely to work for this. Without response from Anenji or your inverter reseller, you probably won't be able to update the firmware, unfortunately.

So what was the problem?

Unfortunately Max II 11kW Twin firmwares are rare; I only have 75.85 for the '28066 processor. So your only option is x75.85 patched firmware, that works around the "stuck at 90V" issue. It includes factory firmware version 75.85 as well. Unfortunately I have no way of knowing how old factory firmware version 75.08 is; 75.85 is from June 2025. You can compare this with the manufacture date of your inverter, to decide if it's worth updating with this firmware.

Having sorted out the mess that is the 43.xx firmware number range, I came across three newer (to me) 43.xx firmwares. The latest of these is 43.29, two days later than 43.28. Perhaps they noticed a whoopsie with the charging and updated the firmware quickly as a result. This is main (U1) factory firmware version 43.29 for the Axpert VM II Premium 3kW and 2.5kW '28062 non-Twin. Do not use with any other model or version. Use at your own risk. The hex file is dated 16/1/2025. Firmware upload instructions for models with a removable display. This firmware processes the QDOP command, so with suitably recent display firmware, it should support SoC% for settings 12,13, and 29 when connected to a suitable battery's BMS. The rar file password is "flash" without the quotes. VMII_Premium_2K5_3K_MAIN_Reflash_Ver43.29 pw flash.rar

There is no "undo procedure", the old firmware is overwritten.

Since your U1 (DSP) firmware is so old, your U2 (display comms) firmware is probably also quite old. So I'd say yes, but there is no great need if you're not having problems.

Ah. These are not passed through by the display firmware. You could try the ATE commands to talk directly to the DSP. I don't know, sorry. Possible, of course. But it seems unlikely that it's the patched firmware. It might be in the 72.62 firmware, and therefore of course also in the 272.62 patched firmware. The firmware is not aware of the branding. As far as I know, it only pokes into the EEPROM to decide whether or not to trigger fault code 90 (clone detected), and no other attempt to discover the model name or reseller is performed.

Control board schematic here, for a related but not identical control board. Note that if the DSP chip itself is damaged, then the board is basically a write-off, due to the issue of finding a bootloader segment that suits the main firmware. You may be able to buy suitable replacement control boards, either from your inverter supplier or Ebay/Ali Express etc, but note that there are many variants with subtle differences, and vendors will often be clueless about these differences. You need a control board with a firmware that matches your model, otherwise you'll likely have an incompatible bootloader segment and will have difficulty reflashing a suitable main firmware. The EEPROM on the control board carries calibrating values for various measurements, so if possible transplant the EEPROM from the old board to any new one. It seems to be possible to use default calibration values, which actually surprises me. Good luck.

Fault code 90 means that the firmware thinks that it is running illegally on a clone. At least, that's what it means for Axperts (off grid models; Infinis are called on-grid models by Voltronic). If it's the same as with Axperts, you need either patched firmware (most unlikely for Infinis), or you have to get an updated firmware or serial number updating tool from your inverter supplier.

What do QFS and QFAULT return?

I see no photos. Why was the control board replaced? What were the firmware versions before and after the change? My guess is that you have a different main (U1) firmware that is incompatible with commands that the display (U2) firmware is sending. Or the U1 firmware on the new board is incompatible with your inverter hardware. I have no 17.xx firmwares at all. Does the inverter work in other respects, other than the display?

Yes. The MAX firmwares are designed for either the '2809 (older) or '28066 chips; the 75.xx firmwares (those designed for MAX models, not the ones for rack mounted Kings) are for the '28066 chips. You have the '28069 chip, which is the same as the '28066 chip except it has a bit more RAM and two extra accelerator modules (not needed or used in the inverter firmware). My guess is that there are occasional shortages of the '28066 chip, so they use the '28069 instead. Or maybe Texas Instruments' fabrication is maturing to the point where the '28069 has the same yield as the '28066, and the '28069 is completely backwards compatible, so they just concentrate on producing the highest spec version, simplifying inventory. I've heard of other '28069 chips in Voltronic inverters. That said, nothing in this crazy world is completely certain, but this one is very close to completely certain.

Display firmware version 03.25 looks much like the 02.xx series, at least at a first pass. Edit: On pass 1.1, I see that the display segments are all different. So this just has a different display, still only with one "head" (colour displays have 3 heads).