Coulomb

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.