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Coulomb last won the day on September 6

Coulomb had the most liked content!

About Coulomb

  • Birthday January 5

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    Brisbane, Australia
  • Interests
    Solar energy systems with storage; firmware for inverters and chargers

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  1. Actually, on reading the documentation again, I no longer hold this theory. With the solar balance setting off, the PV output current should be limited to the value of the total charge current setting. Suppose that's 60 A; that means that you should be able to use up to 60 A of PV charge current (at the 50 V end, so around 3 kW) to support the loads. That's clearly not happening. What I now suspect is happening is what @hoohloc reported; the BMS is sending a "don't charge, don't discharge" command to the BMS, and it's obeying it. Mu suspicion is that the Pylontech BMS is using too high a maximum charge voltage, and that's allowing the battery voltage to exceed 54.0 V, which is the panic level. But I don't understand how the battery voltage is supposed to fall if it's not being discharged. In summary: it looks like the BMS is the root cause. Whether the inverter firmware should be slavishly following the BMS commands is another question.
  2. I don't have time to compare the Growatt and Axpert firmwares, unfortunately. So I don't have a feel for how similar the firmwares are. But a lot of your problems, like this one, sound very familiar. I take it that the new firmware didn't fix the problem. I'm hoping to demonstrate it on the Axpert King that is now installed at Weber's house, and hopefully track it down from there. IF we find the problem in the Axpert, and IF I find that the relevant part of the firmware is similar enough, it MIGHT be possible to patch the Growatt firmware to fix it. No promises. Though it sounds like it's fixed in the 5000TL HVM firmware. It would be interesting if you can get Growatt to fix it for their 3000TLs, making their product better than the Axperts it was presumably copied from. It sounds like the firmwares that are not using the solar power properly are using the solar power exclusively for battery charging. It's like firmware with a Solar Balance setting that is permanently off (or possibly intermittently off). Regardless of whether there is a menu setting and/or command to change that setting. The Axpert command for changing the "solar balance" setting is PSPB. So you could try sending a PSPB1 command (with appropriate CRC characters and carriage return, of course) to see if that helps for a while (until the value gets overwritten again, perhaps). Edit: I've gone off the Solar Power Balance setting theory. See this post. The value used by PSPB in the latest Axpert King firmware still gets passed to the Solar Charge Controller (a separate processor on 145 V max models). I don't see it used in the 450-500 V max PV voltage models. Does this ring true for Growatt models? Edit: please continue to use the @Coulomb mention facility in replies, as I tend to ignore posts with "Growatt" in the title otherwise.
  3. There are some partial schematic traces here: Partial schematic traces. There are also some simplified schematics in the various service manuals; check the files section of this forum. Edit: it's probably not the relay driver, it's more likely the whole power supply collapsing, either due to a fault in the power supply, or something is drawing too much current once the firmware progresses to a certain stage.
  4. I'm 99% sure that these are clones; the metalwork is too different from what we see with the genuine Axperts in any rebranding. But hopefully it will work well for you; it's a roll of the roulette wheel.
  5. That should be a picnic to wire up . Just noticing the picnic tables in the background...
  6. Thanks for the data; I stand corrected. A fairly unusual beast, I think. It must treat the battery port like another PV input, except reversible so the battery can be charged as well as discharged.
  7. I believe that it should. Reading the firmware, I see that the paralleled inverters share the BMS data amongst themselves, for example. I think some earlier King firmwares (both DSP and removable display) had problems with this though. So updating to the latest firmware (71.97 and 02.66 as I post) might help.
  8. My guess is that these were actually wired 4S4P, for a 48 V system. 16 x 12 = 192 V nominal; I've not heard of such an inverter battery voltage. [ Edit: but see next post. ] Please look up the specifications and tells us what the nominal battery voltage for the inverter is. I had a quick search, and could not immediately find it. I can't see how he has 7 12 V modules working in any sensible way. My understanding is that lithium modules can never be wired in series; the resultant voltage would exceed the ability of the silicon switches to safely disconnect the battery in case of a problem (e.g. one or a few individual cells over-voltage).
  9. Good Day Coulomb  have send you a private message.

    1. Coulomb


      ? I've not seen a PM, unless it was a long time ago.

  10. That sounds like the Solar Balance parameter (which can't be changed by a setting in most firmwares) is inadvertently getting cleared. But in two King firmwares (71.92 and 71.97), the solar balance setting isn't used. The global variable is still there, and it can still get set by resetting to factory default settings, but it doesn't seem to affect solar power use. But perhaps the Synapse King is a clone, and uses some very old firmware, or firmware different from the Voltronic Kings.
  11. ? I don't know the Growatts, but I'd be surprised if they didn't allow powering loads with PV, so the PV won't get "switched off" when the batteries are full. ? Again, I don't know about Growatts but I'd be very surprised if they didn't taper the charge as the voltage setting is approached.
  12. You seem to have muffed up the above link. But there were enough clues to lead me to this post: Sorry, I know nothing about WiFi monitoring via the Voltronic Android app. Edit: I'm wondering if the EEPROM faults are due to clones, and/or are likely to lead to fault code 90 (error 90) in the future.
  13. I assume that these are for an Axpert inverter of some sort, not using a BMS cable. Pylontech batteries are 15S LFP. 53.2 V is 3.55 VPC; that's a lot more than 90% SOC. I'd use 51.8 V. You could float at 50.3 V. To have the inverter automatically cut off at about 20% SOC, you'd want setting 29 at 48 V. Unfortunately with unpatched firmware, that makes setting 12 effectively 50 V, which means your inverter will switch to utility powering the loads at about 90% SOC, because of the problem in FAQ #2. With an LFP flavour of patched firmware, the effective back to utility setting is 0.5 V above the cut-off voltage, or 48.5 V, or about 24% SOC (assuming light discharging). These inverters are not designed for frequent load shedding. If your inverter has a 145 V max solar charge controller, then you could run patched firmware; see what can I update firmware to. Yes, though you'll get a solar charge controller reset, meaning that the solar charging will stop for ~30 seconds, stay at 1 A for ~15 seconds, then ramp back up over another 30 seconds. If you want to get back to battery sooner, you could put setting 13 2 V higher than setting 12 permanently. I would not put the two settings any closer, or you could be switching to and from utility and battery modes every several minutes.
  14. I don't like the high voltage SCC models because they don't include insulation monitoring and are therefore unsafe. And therefore illegal to use in Australia, though I'm sure that there are plenty installed here. You also get less total charging current, in the admittedly rare case of combined utility and solar charging. There is also the hassle of leakage when panels are wet, sometimes triggering bus over-voltage errors and other problems. Plus the whole idea of half wave rectified AC superimposed on high voltage DC seems crude to me. But that's just subjective; most transformerless grid tie inverters are the same.
  15. Yes. But only the ones with the high voltage Solar Charge Controllers. Which is the majority of the models now (sadly, in my opinion). That certainly seems to be where the industry is going (high voltage strings). And only in SUB output priority (often called "mode"), as far as I know, but they can do it.
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