Coulomb

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

I would now recommend factory (non patched) firmware version 46.71. Patched firmwares based on factory firmware version 90.06 are now getting a bit old (Feb 2022). This seems common; I don't know the reason. If this still doesn't fix your problem, you could try the original patched firmware based on 90.06 here. With your high voltage panels, the original 200 V variant of the patched firmware should be fine.

There is no special character on the CRC for that command. Not all main firmwares handle the QPIGS2 command but 45.07 does. Not all display firmwares pass through the QPIGS2 command, but 12.13 does. Finally, QPIGS2 is a longer command, 6 characters. When you add two CRCs and a carriage return, that comes to 9 characters. It turns out that in some cases, you have to send such commands in two strings, with no more than 8 characters in each sent string. It's something to do with USB libraries. See the following post, and if interested, two earlier posts: https://forums.aeva.asn.au/viewtopic.php?p=75802#p75802

Whatever these are, they are not Voltronic firmwares, despite the inverters' appearance, and many similarities in the firmwares. Sorry, I can't be more help than that.

The only patched firmware for your model is at present version 281.05. This is a 200 V minimum MPPT version, so DO NOT use this if you have panels that routinely operate best below 200 V. I note that your display photo shows PV1 voltage as 88 V, suggesting that you have few panels on that MPPT. I would not use the 200 V patched firmware with fewer than 6 panels (assuming 72-cell panels, but high wattage panels these days probably have many more cells than that). Your Voc (panel voltage with normal sun and no load) should be at least 260 V. If you have a lower Voc than that and adding panels is not practical, let me know what panels you have and I may be able to produce a lower voltage patch.

That's Litz wire; many strands of thin insulated (varnished) copper wire, to reduce the skin effect. Those bits of red tape are possibly just to hold the bundles together for ease of winding. Maybe they can't get that weird wire to wind by machine. Check with your multimeter. Copper doesn't stay shiny like that for more than a few minutes before tarnishing, unless it's covered with varnish. This happens to be clear varnish, or it's so thin that it appears to be transparent. You really should replace the winding (if necessary) with similar wire. Otherwise, your transformer will get very hot (again?), and efficiency will be poor. I would expect that you would need the exact same number of turns either side of the centre tap, if that's indeed what it is.

That sounds like a 15 kΩ 5W 5% resistor (J is the code for 5%). It's probably the R of an RC snubber network. Perhaps lift one leg of the associated capacitor and check it for short circuit or excessive leakage. It might also be a self healing type; if so, it may have lost significant capacitance, though I would expect that to make the resistor dissipate less power, not more.

That's probably almost entirely reactive, so you won't pay much for that. It's because of the capacitor at the end of the LC (inductor-capacitor) filter, needed to turn the pulses from the DC->AC converter into a smooth sine wave.

As soon as the inverter draws power, the bulb lights and the AC voltage goes out of spec. Can you test with a higher wattage bulb? I assume that you have no AC-out load. I don't know the Growatts at all, but they seem vaguely Axpert-like. Is it possible that a movistor or capacitor has shorted after the "safety" (AC-in) relay(s)? In an Axpert, there are two AC-in relays, in the live and also the neutral circuits. Does the solar charger definitely work now? Sorry, I only briefly checked some of the videos. I'm thinking that perhaps a lingering fault in the solar charger is causing big current draw when the AC-in neutral relay comes on. Remember that PV in minus is usually BUS-, and BUS- has a large potential compared to ground and therefore AC-in neutral. Check for shorts from PV- and PV+ to earth.

Because it's cheap! 🐤🐥🐦

67°C is quite high. Since you can't change the temperature with air, that suggests that the sensor is faulty. Have you measured the heatsink etc temperature with a non-contact thermometer? I don't know about the VM models, but the other models have 3-4 temperature sensors: * Battery and inverter heatsinks (one each) * Transformer (a small sensor on the motherboard, between the transformer(s) and the fans * On the Solar Charge Controller heatsink (not sure if all models have this). The temperature typically reported is the highest of these, so if you're not blowing air on the hottest sensor, it won't change that reading. You might be able to get individual temperature readings with the undocumented (and often changing) Q1 command. Look for a response with 4 or perhaps 3 3-digit fields, that seem to represent temperature in °C: https://forums.aeva.asn.au/viewtopic.php?p=60229&sid=b5a310cb8f884b250075966f49d3d6b5#p60229 It's also possible that some other fault is causing some part to overheat, i.e. the reported temperature and fault code might be real.

The heatsink on top was gone by October 2015.

That sounds like the power supply that runs off panel voltage is not working. The inverter should continue running when the switch is off and there is a charging source (AC-in or PV in). When both sources are absent and the switch goes off, the inverter shuts down after about 30 seconds. You just need to diagnose faults on the solar charging board. There are a few scattered partial schematic traces, e.g. https://forums.aeva.asn.au/viewtopic.php?p=101124#p101124 https://forums.aeva.asn.au/viewtopic.php?p=101874#p101874 It sounds like 4 panels in less than good sunlight aren't enough to get solar charging started. But it could also mean that the solar charger is faulty. It is expected that the panels will drop several volts under load, in fact around 15% (≈0.6 V per cell open circuit, ≈0.5 V per cell under full load).

You seem to be doing repairs on an industrial scale there.

Ah! Excellent point. For a moment I wondered if that caught out the manufacturer's parts buyer, and that's why they all failed. But I think that with such a gross mismatch of rated voltage to actual voltage, that they would not even pass whatever quick test that they do in the factory.

Are you saying that you had to reduce the cross sectional area of the wire, or the number of turns? Reducing the cross sectional area will affect the power rating. Changing the turns ratio will change the voltage at the load end (either the bus end or the battery end, depending on whether the battery is discharging or charging), and this will confuse the firmware, which has a fixed ratio in mind. I don't know what the effects would be. Yes! There is something like one to several volts induced for every turn. If a part of the winding shorts to another winding, then isolation is broken. If one turn shorts to another turn on the same winding, then there is a shorted turn, and that will cause massive currents to flow, probably damaging the driving transistors and/or other components. Normally winding wire is varnished; the varnish is amazingly resilient even when the wire is bent fairly sharply. But the low voltage winding of these transformers has to handle very high current, and not a lot of turns, so the "wire" is more like a bar or rod. But it still needs insulation. Rewinding a transformer is pretty hard core.

The borehole pump will have a substantial switch-on surge, probably 5-7x the rated power. This in addition to your other loads could easily overload the inverter, especially if it's relying on the battery, and the battery is weak.

That appears to be a VM IV 5.6 kW Twin. Both the DSP 12.xx and the display 63.xx are quite rare. I have no firmware update files for either of those, sorry. [ Edit: Sigh! I see that the sticker says that it's rated at 8000W. So now I have no idea what that firmware is. ] It might be possible to update to a later main (DSP, U1) VM III or VM IV 5.6 kW Twin firmware with a different major firmware version number, but I strongly do not recommend it.

That might be a bit low for reliable operation. It it possible to add one or two panels? You could try updating the main firmware; 60.10 is about 6 months later than 60.89: 49 Hz might be part of the problem, especially if it's not particularly stable. It might also be worth switching the inverter to 220 V operation; by default, it's expecting 230 V.

Yes, here:

I assume you mean that you checked all the diodes, transistors, resistors, and zeners in the MOSFET driver circuit. Perhaps the SG3525 or its power supply, or near components? What about the small (TO-92) MOSFETs that seem to be for turning off the main MOSFET gate drive? That's weird. Have you checked the DC-DC IGBTs at the high voltage end? It sounds to me like maybe an upper and lower pair are turning on and shorting the DC bus. Maybe. Sorry, I just can't understand that. What exactly are you measuring here? Power supply? Gate signals? The gate signals should be switching from around -5.6 V to +13ish volts, when the DC-DC converter is enabled. Respect for getting the transformer unsoldered without completely butchering the PCB, on the top side at least.

Hmmm. That QR code seems to decode to "You successfully scan QR code". The label doesn't look quite right. The first 4 digits of the serial number (9632) aren't a pattern that I've seen, but I haven't been seeking them out lately. I get the feeling that this is a clone, and the firmware is a copy of some unknown Voltronic firmware. It's obviously not a copy of a VM IV (no round display), and the display is at the very left like a VM III, and the MPPT range is 60-450 V like a VM III. So my guess is that it's a VM III clone. Probably a non-twin, since I'd expect a Twin model to say so on the label (but that's just what I'd expect, not definite at all). Also, 19.xx is a Voltronic non-Twin display firmware for the new style VM IIIs. But you can tell if it has two AC output terminals; if so, it's a Twin, if not, it's a non-Twin. Since the VM models all use the same processor chip ('28062), it's possible that this inverter is compatible with Voltronic 55.xx firmware. The only one of these in my collection us 55.06, and it's from October 2022. I see from your serial number that your inverter is from early 2023, so whatever that 72.00 firmware is, it's probably more recent than that. You could possibly update to Voltronic display firmware version 19.18, but there doesn't seem much point, and plenty of risk.

Sorry, the "policy" parts of the firmware are still opaque to me. I've had a few goes at it on the Axpert King in particular, but can't seem to make a breakthrough. Certainly when the battery is full and goes to float, it's normal for the battery to discharge slightly (about 0.5% SoC with an LFP battery). But there seems to be much more going on here.

A current limited power supply is best, but note that if the power switch is on, it will try to start the DC-AC converter, which will likely be too high a power surge for a typical bench power supply. You can use a set of 12 V batteries, but use inrush protection to prevent a massive current spike and splat. This is not good for the wiring, connectors, capacitors, and even your eyes.