Coulomb

There is a collection of some partial schematic traces here, including some of the paralleling boards. I came across this post, where a PIP-5048 owner fixed a fault code 80 issue by replacing paralleling boards.

This is on the edge of my knowledge, so treat accordingly. I'm uneasy about it. The replacement for the choke wires would obviously have to be quite high voltage rated; audio cables would break down quickly with catastrophic results. With respect to protective earth, one end of the inductor has a high dV/dt 50 Hz square wave of amplitude equal to bus voltage plus the PV voltage. The other end has that plus a ≈20 kHz square wave also with bus voltage amplitude. The capacitance from wire to braid will be low, but with all this dV/dt, the current will be significant. I worry that this current could increase losses in the two converters (the 50 Hz DC<->AC converter and the MPPT boost converter) such that they could fail under some conditions.

My understanding is that MKS IIs drive the display directly from the main DSP chip; therefore there is no U2 firmware version. My file post suggests a "2.2μF 600 VDC X2 class polyester film capacitor". https://powerforum.co.za/topic/15724-axpert-mks-iv-5600-corrupted-display/?do=findComment&comment=173515 This is the crux of it: Unfortunately, 71.xx is a number range shared by several different models, including the PIP-5048 MGX. This version has a removable display, and is sometimes known as an Axpert MKS III, but is possibly mainly or only used in the MPPSolar model. So it's hard to say. It should be safe I think, but the nearest firmware version I have to 71.20 is 71.17, for the MGX. Does your model have a removable display? 1: I don't believe that any firmwares have "hardening" against fault code 80. The firmware relies on the hardware to deliver uncorrupted messages. 2: Again, hard to say, since I don't have a copy of 71.20. I suggest that you try dressing the cables and adding the capacitor first. Please be careful with high voltage DC and largish capacitors; these can store lethal energy for many hours if there is no bleed path.

Sorry, I have no knowledge at all of 01.xx display firmware. 20.xx display firmware is for new VM IIIs, with power ratings like 4 kW and 6 kW. So I believe that those will not work. Whether 02.xx firmware will work, I have no idea either, sorry. VM III firmware version numbers are such a mess.

I don't know of any 38.xx main firmware. And the remote panel / display firmware has many jobs, including communicating with the battery BMSs. It's not clear to me how much support the main firmware needs to support more than one BMS battery type; I suspect it's no more than is already needed to support Pylontech protocol. But if more is needed, you'll have to tell me what version your existing main (U1) firmware is.

Strangely, I have no 35.xx display firmwares in my collection at all. If you are DESPERATE, you could try the latest 22.xx display firmware. I have no idea why there is more than one Max II (and VM IV) non-Twin display firmware, and what the consequences are of mixing them. This is factory display (U2) firmware for the Axpert Max II (with colour display, NOT the removable display) or Axpert VM IV, non-Twin. Do not use with any other model. This display firmware may or may not work with models that come with display firmware 35.xx. Use at your own risk. Hex file is dated 16/May/2024. It has the QDOP command, so when paired with suitable DSP firmware and connected to a battery BMS, three settings should use SoC% instead of battery voltage when using the display directly (not via monitoring software, I believe). Remote Panel_Reflash_MCU(22.25).rar

It could be that the capacitor modification is required, or if present, the capacitor may have lost value due to transients blowing some of the "fuses" that are often inside this type of capacitor. Models with the high PV voltage (450 V or 500 V) seem to be susceptible to this. High dV/dt on the PV wires seems to induce glitches into various communications lines, including the CAN bus connections from master to slave. The OP mentioned the problem being worse around midday, when presumably PV activity is greatest. Redressing some of the cables may also help (see link in the below).

VM III firmware numbering is a mystery to me. Main firmware version 41.18 is available here, and is for VM IIIs. There is also a link there to 02.89 (see below). But whether 41.18 will work with an inverter currently running 20.58, I have no idea, sorry. I would first try 20.59, available here. I can't make any sense of your U2 version numbers, sorry. 20.xx display firmwares are for the new VM III models (with power ratings of 4kW or 6kW), so I don't believe that they will work. I believe you need 02.xx (was 01.21 a typographical error perhaps?), the latest of which is 02.89.

The bit rate is fixed by the firmware; the reflash tool ignores any speed settings in Windows. So that indicates that your serial to USB adapter, PC etc are all working fine. So the problem has to be with that particular inverter. Is it possible to swap displays to see if the problem is in the display or the inverter proper? There may be problems with Twin versus non-Twin, Duplex versus non-Duplex etc.

That would seem to indicate that the patch is working. I would not think so. At a quick glance, I don't see any derating related to line voltage. Is it possible that you don't have more than about 5 kW of PV power (100 A at ≈50 V battery) available at this time of year? Is the 115-120 A charging repeatable?

It's possible that you need the resistor in the serial cable, details in this post. I'm afraid that I don't understand this issue at all. It's also possible that the opto couplers in your display and/or inside the inverter are getting old and slow; they do apparently deteriorate with age. Maybe the DSP firmware is larger or the flash firmware is somehow more demanding of time, or the fact that it has to go through the display has something to do with it. That's pretty weird, though I guess it fits best with the slow opto coupler theory. Though normal operation is at 2400 bps, while reflashing is at 9600 bps, so even if the optos are marginal at 9600 bps,, once you get through a firmware update they should be fine. Could it be noise from the PV wiring? Were you flashing during the day with the PV connected when you had problems? If so, you might need the capacitor mod, though this usually affects only the display.

I don't have 38.16 in my collection, but I have 38.19, which should have all the features of 38.16. It is available here.

I finally found firmware version 82.07 for the Axpert Max II 10kW '28066 non-Twin. So I've now patched it. This is patched firmware version x82.07, based on factory firmware version 82.07 for the Axpert Max 10kW '28066 non-Twin. Do not use with any other model. The original hex (.inv) file is dated 23/10/2024. This firmware works around the "stuck at 90 V" problem with a suite of patches, including changing the current threshold from 0.50 A to 0.10 A. It also fixes the premature float bug, and changes the reported version number to x82.07 (e.g. 382.07). The front panel display will continue to show version U1 82 07. It also optionally changes the PV voltage at which charge current starts derating from 360 V to 450 V. Use at your own risk; I cannot test this firmware as I do not own an Axpert Max. It has been "sanity checked" by disassembling the firmware and confirming that the intended changes are present. Firmware upload instructions. https://forums.aeva.asn.au/viewtopic.php?p=87767#p87767 Choose the minimum MPPT voltage that is higher than your working panel voltage even in poor light. With each pair, the one with the derating PV voltage change is the one with the higher first digit. dsp_282.07_patched.inv: Minimum MPPT voltage 200V, no derating PV voltage change. dsp_382.07_patched.inv: Minimum MPPT voltage 200V, derating PV voltage changed to 450 V. dsp_182.07_patched.inv: Minimum MPPT voltage 150V, no derating PV voltage change. dsp_582.07_patched.inv: Minimum MPPT voltage 150V, derating PV voltage changed to 450 V. dsp_882.07_patched.inv: Minimum MPPT voltage 90V, no derating PV voltage change. For extremely low panel voltage. dsp_982.07_patched.inv: Minimum MPPT voltage 90V, derating PV voltage changed to 450 V. For extremely low panel voltage. dsp_original_82.07: Unpatched factory firmware version 82.07. dsp x82.07_patched Max II 10kW non-Twin.zip

Yes, it's 82.63, which has the "presumed good" MPPT algorithm. Sorry for the extremely late response to this.

No, the two EEPROM layouts are identical. So that's not the issue. Intriguingly, the hex file for 56.13 is three days later than that for 56.14. Both are definitely Infini firmwares, as confirmed by the folder names. So sorry, I have no idea what the issue is. Interference is possible, but it seems unlikely to me.