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Green Power

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  1. The issue has greatly reduced, I don´t think as a result of anything I did, but it just seemed to get better. Only theory I can really think of it is it was to do with the hot weather somehow, some component overheating or something. It seemed to get better when the weather cooled a bit. Totally guessing though. Probably isn´t that. I half expect this issue to recur at some point, however.
  2. Thanks for your comments. Assuming the performance of my system doesn't deteriorate rapidly with this issue, then I will likely wait until later to deal with this, possibly the second half of March as I have a couple of trips coming up and I'll want to be home to keep an eye on it.
  3. Yes, stable load. Voltage also seems to be OK, but haven't watched closely. Good idea on the wiring but everything looks OK to me, not that I'd necessarily be able to tell. Do I really need to set the loads to zero to Coulomb for the firmware update to work? Can I at least leave the internet box on and have a low load of 30 or 40W? I want a low carbon lifestyle to be attractive to my family and others, if it's really necessary to set loads to zero I'll probably wait until the next time I will be at home alone to do the firmware update. That would be mid to late March most likely. Is there any significant chance at all that the firmware update will make this work, or cause the inverter to stop working? Or is the realistic worst case scenario that it doesn't work and I'm just back where I started?
  4. A firmware update is worth looking into. I will check it out. The inverter is: Axpert MKS II 5kW UI 71 80 is what appears on the inverter and I think is the firmware. I think I discussed this with @Coulomb once. Does this look right:.It is 2021 so maybe we need something like this but more recent. Not sure how you actually update firmware. I assume you need the right cable to connect a laptop to the inverter. Is there someone with basic instructions?
  5. Here is a video: https://vimeo.com/manage/videos/797553667 (Please ignore the flashing number 4 error. That is a low battery warming that wrongly happens all the time, I think because this inverter was designed to work with lead acid batteries so it just correlates something like 48V or 49V = low battery which doesn't make sense for the lithium batteries it is currently working with. This flashing error is almost certainly nothing to do with the solar input variation so don't be distracted by this.)
  6. My solar input is flickering around like mad. It will show 2000W generation then a second later 1500W then back to 2000W then 200W for a fraction of a second, it's all over the place. This is not due to cloud, happens in clear blue sky. When it is at 2000W that is where it should be, when it has fallen down to lower it looks like some solar is being wasted somehow. It happens a lot, I reckon I am losing at least a few percent of my total generation. Mostly happens in middle of sunny days. I did wonder if it was the battery not accepting the solar, but this also happens sometimes when load is greater than solar input, so perhaps not. Certainly if the battery is full solar input displayed falls, as I don't sell back to the grid. I suspect the inverter a bit, but replacing the inverter would be a case of the medicine being worse than the illness given the cost and hassle. It's also not going to be worth spending hours and hours on this, or paying for a professional to look at this, at least not for now. I am also a little worried about the affect on the inverter lifetime of having the solar input constantly jumping about the place. It makes more noise when this is happening and seems to be working harder. Any idea what's going on? Or ideas to fix? Or does this error/behaviour have a name so I can google it for more info?
  7. 6 weeks since the BMS board was replaced; error has not repeated; not even once. Looks likely the correct fix was done. The battery charge levels still go out of alignment by 2% - 5% as before, e.g. one battery might be at 68% and another at 72%. So likely that has nothing to do with the problem. Edit Feb 2023: Now nearly a year, still fine.
  8. I will try and figure out how to do that at some point. If you would like to suggest a method, or point to an online article showing the procedure, I can look into it
  9. The battery BMS board (tarjeta de control in Spanish) has been replaced and the battery returned to me and the system is now working again with two batteries Since the error previously occurred occasionally in the past with gaps of days or weeks in between we won't know for sure if this was the correct solution to stop the error until some time has passed - maybe a month or two. This also confirms that the guarantee's vaidity has been accepted in spite of using the battery with an inverter with no communication. I was not charged for the replacement.
  10. Pylontech had suggested sending the board to me but the installation instructions looked tricky for me so instead it was arranged to leave the battery with the company that sold the battery, where it currently is. May have further update in June.
  11. It is Axpert MKS II 5kW, no communication with this battery.
  12. Update: Pylontech told me to buy a RJ45-DB9-USB cable and rewire it to their instruction. I got a computer shop to do that. This then enabled me to, via a software program and some instructions they sent me, take the logs of data out of the battery and send them to Pylontech, who told me that "I think the problem is on the battery BMS board" so they are going to send me a new board.
  13. Summary: If you don't have time to read all this the bottom line is I decided to run the system off one battery until issue is fixed later. (comment is 880 words, 2 minutes to read) EDIT June 2022: Suggest skip this long comment for most people, it was a mix of temporary solutions, random asides, and dead ends. It doesn't cover the eventual solution. The fault has been regularly occurring still. If I turn off the battery and then turn it back on again only minutes later, and do nothing else, the fault never instantly reappears, but will reliably recur minutes or hours later, at the most the next day. Batteries tend to be out of balance after the fault, especially if I detect the fault at 6am or 7am which means it could have been in the faulty condition for hours as the alarm is not quite loud enough to wake me to the other end of the house. This unbalance (which happened a few times in the last weeks) suggests that when the battery is in the fault condition it is probably not discharging. In some cases when this happened I then disconnected the batteries and did a partial or full rebalancing before connecting. When I did this, then the fault will not recur as soon, but will still recur after perhaps a few days or a week. There is insufficient data to draw a conclusion with high probability, but my gut feeling is that the benefit of battery balancing is to give the battery time to rest and recover from heavy demand situations, rather than because of the actual balancing benefit itself. To test this theory I just turned the batteries off for over a day recently and it was 2 days later that the fault occurred. Similar to when I do battery balancing. Last night I tried turning the one faulty battery off and back on again after only 30 minutes, but the error repeated within a few hours. I then left just one battery off overnight. The single battery was still able to handle a 2000W load. However after turning off the faulty battery a red fault light (no flashing, nothing audible) was displayed on the master battery, and the 6 LED lights on the master battery showing SOC did not display. However it still worked - during steady discharge at low load for maybe 10 hours. I turned the bottom battery back on this morning so I didn't get to test charging with the one battery turned off. When I turned the bottom, faulty battery back on the red fault light disappeared immediately and the SOC lights immediately returned also. Interestingly, when I turned the batteries back on they were heavily unbalanced with one showing one light and the other four, however, impressively, the two batteries then balanced each other out over a few hours. At one point one of the batteries was actually charging even though the whole system was discharging (i.e. loads > PV input). So all the times I disconnected the batteries to balance them in isolation from the inverter and the rest of the system may not have even been necessary. I am am able to turn the faulty battery off and on again without causing a power cut if I don't turn off the other battery. This is the only way I've found to reliably create a short term fix to the error without a power cut. However, given the fault light and the non-display of SOC, this makes me uncomfortable as there may be a possibility, however slight, that I could damage the top battery in this arrangement of passing circuit through the turned off battery. I therefore now completely disconnected (and turned off) the faulty battery for now and connected both long cables to the top battery. I have not changed the dip positions. I have reduced the charging current from 30A to 20A but kept other inverter settings the same. I attach a photo with the current cable connections if anyone wants to check it. I currently plan to only connect it if necessary to do so as part of an attempt to solve the problem or if we had a grid power cut and it's the only power we have left. I am storing the battery at 50% charge level, by the way, and if it gets cold out there (nearer to zero degrees than ten) I will move the battery into another storage location in the house. Given this, it seems like that should be OK to store it for months turned off if necessary (according to a few articles I just read including some graphs). I'm too busy to properly solve this this week. It looks like the issue needs software diagnostic with Pylontech at this point and failing success with that to try and get the battery replaced or repaired. I will try and get to that within May and then provide an update. It looks at the moment less likely that the error is caused by communication issues or current flow from the faulty battery to the inverter or the other battery. And perhaps more likely that there is an internal issue with one of the faulty batteries. I am concerned about running the system with one battery as it is quite undersized for the evening demand. 2000W evening demand will work but is above the recommendation and could affect lifetime. I don't know what happens with 4000W or so demand in the evening, but hopefully would default to grid. However, this seems to be the best solution for now. I may also try this is a permanent solution if I can't get the battery repaired or replaced under warranty.
  14. Can someone let me know please if I can turn off just the one faulty battery when the fault occurs (this would be for minutes, hours, or 1-2 days at max). This would leave one battery turned on and still connected to the inverter via the orange cable. Can it still work by passing current through the switched off battery to get to the black cable? Is it safe to leave one operating in this configuration and the other off? Might it be the case that the top battery could still function to charge but not discharge? Or vice versa? Parallel circuit, see photo. @Coulomb@Beat
  15. Thanks everyone for helping out. The error is happening more frequently now, 4 times in last 48 hours with 3 of those since I changed to bulk charging voltage 51.8V, Floating charging voltage 51.0V. Not sure whether to set the voltage back to the Pylontech recommended 52.5V or whether to just keep bringing the voltages lower and lower. However, guessing quite likely none of that will work. My guess is there is NOT a mismatch of several volts between the inverter and the battery because the voltage shown when discharging at low load is consistent with what you would expect for a given state of charge shown on the battery. I think I may disconnect the one battery and run the system off one battery, at least for a while, if this keeps happening. So what I am thinking is connect the long cables to the master battery, presumably same dip position, remove short cables and other battery. Probably reduce max charging amps, other settings the same. Does that seem reasonable for just one battery? Would it make sense to switch over the master and slave positions- I can´t think why it would work, but maybe worth a try. Or maybe I´m just getting desperate at this point. Would it make sense to leave the faulty battery disconnected for a longer time? Several days or a week turned off rather than switching it back on after minutes or hours. Not sure if that would give voltage levels a chance to settle down and smooth out? Pylontech suggests I buy a RJ45-DB9-USB cable to download the logs(event data and cycle data) and send it them and then they can do a diagnostic on the battery problem. I can try it if I can find anywhere to buy the cable, although it looks complicated. It could be a faulty cell, a faulty battery, or some fundamental problem caused by the lack of communication between inverter and battery. On the other hand sometimes when you are just about ready to go for the nuclear option there appears some extremely simple solution that you´ve overlooked...
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