Coulomb

The latest firmware for your model is over a year old now, but it has the "presumed good" MPPT logic (so the "stuck at 90 V issue is largely solved). It's 46.82, available here: https://forums.aeva.asn.au/viewtopic.php?p=102981#p102981 Edit: You may want to update the display firmware as well, as 112.19 is quite old. The latest in the y12.xx display firmwares is display firmware version 12.28.

The output smoothing capacitor (the "C" of the "LC filter") is only about 10-20 μF (for 3-5 kVA models); these are large rectangular film capacitors, non-polarised. Did you mean the bus capacitors (typically 2 x 470μF for 5 kVA models, polarised), or confusing the two, or... ? I believe that the 2SA1020 is PNP. Almost certainly not. My understanding is that most of the time this power supply operates on battery voltage, so that would be twice as high on the 48 V models. These circuits can operate over a wide voltage range, but I don't think that wide. Have you replaced the SG3525? Also check for bad solder joints on the tiny capacitors. I had a King 5 kW that had the timing capacitor intermittently open circuit. Also check the larger chip capacitors out of circuit; those things are barely able to be called capacitors, and can drift and change capacitance with applied voltage. The larger valued ones (usually only used for bypassing) are the worst, as they need the more extreme permittivity materials, which have the worst parameter spread.

Duh! Yes. Too many firmwares! Edited. Thanks for the pointer. Comparing firmwares is a big job, and a lot of the changes are presumably in the BMS comms part, which I'm less familiar with. So sorry, I have not compared these two. Yes, though it's possible that the other way around won't work (new display firmware sends new commands to the DSP, and gets stuck when the DSP just NAKs the new commands. Yes, you have plenty of panel voltage for the 200 V minimum MPPT voltage variant (260.10).

I don't recommend this practice. The PV inputs are not isolated from earth, so the chassis will be live when doing this! Connecting AC-in at the same time as PV-in would result in severe damage, I would think. On top of that, the capacitors retain a lethal charge for a long time, and the in-rush current will be severe unless you mitigate against it.

I'm not sure that it's merely a firmware change. There may be subtle changes, like to air flow, PCB trace augmentation, more silver on the relay contacts etc, that makes this unsafe. But if someone knows more, I'd be very interested.

Please see the last 2 posts on this thread. We really need that U1 firmware version to help you. Also a photo of the sticker on the side would help to determine if it's a clone or not. F90 is supposed to indicate that this is a clone running stolen firmware.

So you're getting U03 error code; that means "Document inside the USB disk with wrong format." As far as I know, the USB stick has to be empty with just one hex file on it, and it must be called "dsp.hex" without the quotes. I don't know how the USB stick should be formatted (NTFS, FAT32, etc). Perhaps others who have succeeded can say. Be very careful that you have the right firmware update file; I've just realised that using the USB stick method bypasses the "sanity check" for the right kind of firmware (e.g. Kings get a different firmware to others, 2806x processors have their own, etc). In particular, the early Axpert Max E 8kW models had a lot of 90.xx firmwares. Voltronic seem to have stopped using this series, as they were a mix of wildly different models with no pattern. 90.45 might be for a totally different model than 90.46 as a contrived example.

Yes, the 24 V Kings have exactly half (3 of 6, as of display firmware version 02.83) of the protocols that the 48 V models support. The 48 V models also support protocols WEC, SOL, and LIA. I'm pretty sure that these 3 extra protocols are the CAN bus protocols. Presumably the 24 V models' main firmware therefore doesn't need to support CAN bus interrupts, so they can presumably get away with a cheaper DSP chip (at a wild guess). Your BMS protocol seems to have a protocol that starts with a DD byte and ends with a 07 byte, and uses a simple 16 bit checksum. That doesn't match any of PYL, LIC (which are very similar and share a lot of code), and LIB. LIB uses an 8-bit CRC as far as I can tell. PYL (and I assume therefore also LIC) has a quite different command structure. As an aside, it's scary when the protocol manual uses "bit" where it obviously means "byte", says "if zero" when it's obviously "if non-zero", to mention two errors that I noticed immediately. But full marks @fhocorp for finding the protocol document at all. So sorry, I'm 98% sure that none of the three available protocols matches (but you pretty much knew that already), and yes, it would be a huge messy job to implement it ☹️. One protocol that Voltronic seems to be reserving the later is the SH (Shoto) protocol, and it's possible that future firmwares will implement it. From a brief search, this seems to start with a 07 byte and end with a 0D byte. So that's different to the JBD protocol.

For those waiting for VM III firmware version 60.10 to be patched, here it is. These are patched firmwares version x60.10, based on factory firmware version 60.10 for the Axpert VM III Twin 6kW, 4kW, and 1.5kW, and the Axpert VM IV Twin 6kW, 4kW and 1.5kW. These patches implement most of Georg's MPPT "stuck at 90V" patches (here it would be "stuck at 60 V"), and fix the premature float bug. The only patches not applied are for the forward current constant, which doesn't seem to be changed based on solar voltage in any VM firmwares. The version number should display in full when using monitoring software, but will still show as 60.06 on the front panel display. Do not use with any other models, not even older VM III and VM IV models with power ratings like 5 kW or 3 kW, or non-twin models. Use at your own risk. In the reflash tool, you may have to navigate to the folder with the patched files the first time it is run. Choose the hex file with the minimum MPPT voltage you want: 90, 100, 150, or 200 V, or choose the one with no MPPT patches at all (see below). Use a minimum MPPT voltage that your panels rarely go below unless it's so dark that there is no significant solar power available. This will depend on how many and what type of panels that you have, and may benefit from some experimentation. 960.10 has a minimum MPPT voltage of 90 V. Use this if you have the bare minimum number of panels (e.g. 4 72-cell panels). 160.10 has a minimum MPPT voltage of 100 V. 560.10 has a minimum MPPT voltage of 150 V. 260.10 has a minimum MPPT voltage of 200 V. 860.10 has no MPPT patches at all, just the premature float patch. dsp_original.hex is the unpatched original (factory) firmware version 60.10, in case you want to revert to the original. Firmware upload instructions for models with a removable or round display. dsp x60.10_patched.zip Edit Jan 2025: In some VM patched firmwares, I used simple code that unfortunately failed to ever reach the float stage. This patched firmware does not have that problem, and as far as I can tell it never did. Earlier patched firmware versions x60.06 had the bad premature float bug code.

Please all, post in English. There is no problem "going backwards" in firmware version, they are not really "ordered". 46.71 is available here:

What is the present main (U1, dsp) firmware version?

If that BMS happens to use one of the supported BMS protocols, then it's just a matter of choosing the right battery type setting and setting up some device to translate RS-485 to RS-232. That's assuming that a 24 V King can talk via its BMS port... Do you have settings like Pylontech or LIB for battery type? If it's not a standard protocol, then it's a monumental task.

Thus, the inverter isn't talking to the battery's BMS. So the SoC% given by the inverter is a poor guess. Usually there are LEDs or similar on the battery indicating coarse SoC, or there is an app that you can get that talks to the BMS to get the true SoC. Just ignore the inverter's SoC and battery "bar graph".

Yes. Also 1500W 24V.

All Voltronic factory firmwares have the premature float bug. It's company policy, evidently. The VM firmwares have the bug implemented completely differently, in a completely different part of the firmware, compared to all the other firmwares. So it's firmly entrenched. For reasons that continue to elude me, people don't seem to be all that bothered by this bug. So I've stopped making noise about it, and just quietly fixing it in virtually any firmware that I patch.

Is that according to the battery or according to the inverter? A lot of the time, the inverter is assuming a lead acid battery, and has no real clue what the battery state of charge actually is.

There is 31.06, but it's for a 3000VA / 5000VA Axpert. My guess is that the 3200 W is a marketing claim, and the actual firmware limit is 3000 W. What does monitoring software say about the rated power?

You can use any of the 90.06 based patched firmwares. But I suggest that you use 46.71 now, available here. It should work the same with any panel configuration, and I believe it will work almost as well as the patched firmwares. It's almost 2 years old now, but it should still be better than your existing firmware, which I believe is about 15 month older again.

Sigh. "Over the page" forum bug bit.

My apologies if I've inadvertently responded to an old post. My laptop's track pad has been going crazy today.

Yes, and I forgot to mention this important point: AS LONG AS BOTH INVERTERS ARE IN SINGLE (SNG) OUTPUT MODE, and also you DON'T CONNECT THE AC OUTPUT LIVES TOGETHER. Then they are just two independent systems that happen to have their neutrals connected together. The batteries are isolated, you you can connect their negatives to each other if you want. However, if in the future you want to connect three inverters in a three-phase configuration, then you need to put the three outputs into 3P1, 3P2, and 3P3 output modes, you will need the paralleling boards, and the batteries will then have to be all commoned. You would need three-phase utility in that case, or if only single phase, connect to only one of the three inverters' AC-in terminals. Oops, I don't think that would be good, because if one of the inverters gets overloaded, or the battery becomes weak, it would attempt to go into bypass mode, and the three-phase loads would get only a single phase. This could burn up motor windings, I would think, as thee will be no rotating magnetic field, so the motor won't turn, so there will be no back-EMF, and the motor will be perpetually in start-up surge. I'm not experienced with 3-phase configuration of these inverters, so please someone correct me if I'm wrong.

No. I haven't studied the BMS comms code. I would start with the display/comms firmware; the latest I know of is 02.87, available here (ignore the King main firmware also in that post). Alas, I'm not aware of any more recent main firmwares in the 41.xx range. Hopefully the display firmware will fix the problem. Otherwise, you may have to risk later VM 3 3 kW firmware in other version number ranges. I don't know the consequences of this.

My understanding is that you split the command to send the long command into two, sending just the first 8 characters in the first call, and the remaining (just the carriage return in this case, but sometimes more) in the second. But avoiding the USB port (and hence the Python USB library) altogether is another way.

I repeat, I strongly recommend sticking to the original turns ratio. The firmware will not be able to properly control bus voltage or battery charging otherwise.

This is patched firmware version x56.09 for the Axpert Max II 10 kW '2809 non-Twin, based on factory firmware version 56.09. That factory firmware's hex file is dated 2023-9-05. Do not use with any other model. Use at your own risk. This series implements all of Georg594's original patches. They also fix the premature float bug, and report a 5 digit firmware version to monitoring software. dsp_256.09_patched.hex has a 200V minimum PV voltage. dsp_556.09_patched.hex has a 150V minimum PV voltage. dsp_156.09_patched.hex has a 120V minimum PV voltage. dsp_original.hex is factory firmware version 56.09. In the zip file, dsp.hex is the same as dsp_256.09_patched.hex, ready to use with the old reflash tool (it only looks for the fixed filename dsp.hex). Firmware upload instructions for models with a round display. dsp x56.09 patched Max II 10kW '2809.zip