January 14, 20242 yr hi guys Today I got very strange issue. Due to thin layer of snow morning solar power was not best (about 85W) so i decided to went to roof and clear panels with the brush. When returned I checked the solar power and found that inverter produces 5-10W when PV voltage was pretty good. I was pretty confused. I turned off and then on solar panels. It didn't help immediately. But after a while inverter returned to good conditions and begun produced 300-400W from panels. Unfortunately after a hour and half it again begun work in 5-10W mode. And after about 2 hours it begun working again. It seems I never saw such behavior before. MPPT in the King sometimes stuck for short periods, but not for so long as today. It's not first time when I cleaning panels and do it carefully, so I think I didn't any damage. What it can be? Is it a sign of some defects in MPPT board or can some circuit issue in 2s5p panels inspire such behavior? Does anyone saw similar issues? King + 2xUS5000 + 10x460W panels(2s5p) Thanks
January 14, 20242 yr Author At the moment it works and I hope it will continue work well. What confused me it that was not cloudy when I saw these pauses in solar generation. So i begun suspect that there is some issue with the system.
January 14, 20242 yr What is your main (U1) firmware version? If earlier than 71.94 or so, there were strange PV problems, including "dips" and "freezes". 72.00 is available in the files section of this forum. Otherwise, like you say, it's really weird, and I have no idea what's going on. My suspicion would be something to do with water (melted snow) and panels or their wiring; maybe there is a leakage somewhere, but that should hardly stop a 5P setup. Unless perhaps the water gets into connectors after the panels are paralleled. The long time constant (hours) suggests either temperature or something getting wet and drying out over time. Or of course simply intermittent.
January 14, 20242 yr Author 20 minutes ago, Coulomb said: What is your main (U1) firmware version? If earlier than 71.94 or so, there were strange PV problems, including "dips" and "freezes". 72.00 is available in the files section of this forum. hi Thanks for reply. I saw on the forum that older firmware may have issues, but my is newest U1 72.00, U2 102.73, U3 00.24, U4 01.21 I though about some connector issue, but it's 5P and all pairs connected not on the field, but in water proof Schneider Electric box on a wall... After second "self repair" it seems was working as expected till the sun went down. I hope tomorrow this issue will not reproduced
January 15, 20242 yr 18 hours ago, Vitaliy said: I thought about some connector issue, but it's 5P and all pairs connected not on the field, but in water proof Schneider Electric box on a wall... I see cables not in conduit on the roof, I see panels flat against what I assume is a flat roof, and I see many MC4 connectors or fuses sitting out in the weather. None of these is good. Also, it looks like a lot more wires are coming off the roof than going into that waterproof box; if so there must be other junctions somewhere. But it might just be a trick of perspective. There is plenty potential (pun not intended) for weather related problems there. All those connections should be tucked under the panels, ideally all the cables should some through proper grommets through the roof, so no cables should be visible from above (and hence exposed to the weather). I'd say that this is the heart of your problem.
January 15, 20242 yr Author 11 hours ago, Coulomb said: I see cables not in conduit on the roof, I see panels flat against what I assume is a flat roof, and I see many MC4 connectors or fuses sitting out in the weather. None of these is good. I used french Nexans 6mm2 photovoltaic cable with 3 layers of insulation and UV radiation protection. I thought that designed to be enough resistant to outdoor conditions including working under direct sun radiation. If it's wrong expectation I will research on web and maybe cover cables with some additional isolation tape or some conduit. And basically as far as I know MC4 connectors also designed to be waterproof and work in outdoor conditions. I was put all wiring on the edge of panels with idea that it will allow easily re-commutate wiring if i will change inverter to an another high voltage model or if i decided to change panels pairing scheme. (Honestly to do this I had to design and make on 3d printer special cable holders). Unfortunately, this roof has just 7 degree angle and not best azimuth, but I have no better place for panels. There is 10-15 cm space between the roof and panels. Btw, I mounted all the stuff by myself. It's completely DIY project :) 11 hours ago, Coulomb said: Also, it looks like a lot more wires are coming off the roof than going into that waterproof box; if so there must be other junctions somewhere. But it might just be a trick of perspective. No, there are exactly 5 pairs of cable which routed from panels to the box. 11 hours ago, Coulomb said: There is plenty potential (pun not intended) for weather related problems there. All those connections should be tucked under the panels, ideally all the cables should some through proper grommets through the roof, so no cables should be visible from above (and hence exposed to the weather). I'd say that this is the heart of your problem. Basically, I think that's I can't imagine connection problem in 5P system that can produce such symptoms. Taking in account that in time of low generation the inverter showed pretty good PV voltage 98-99V. If one of strings had bad connection it will produce 20% lower generation than usual in similar conditions, but not 10W. If some string had short circuit through a water - this, I guess, had to produce drop of PV voltage of the panels system. But all was looking like the inverter just won't to consume. So at the moment my bet is that the firmware even 72.00 version probably still have some sporadic issue with MPPT driving algorithm that of course much less frequent then in older versions but not resolved completely. At least until I will realize what is exact root cause if it really connection problems. PS. today it was working well Edited January 15, 20242 yr by Vitaliy
January 16, 20242 yr Hi Vitality I also have a king model (Axpert King II Twin 6.2 kVA) and I am experiancing a simular issue with the MPPT dropping but it seems to mostly happen between 1.2 and 1.9 kw generation, after it reaches 2kw then it's ok. I am currenty in the process of updating the firmware but as usual nothing is easy
January 17, 20242 yr On 2024/01/16 at 5:52 AM, Vitaliy said: Basically, I think that's I can't imagine connection problem in 5P system that can produce such symptoms. Yes, I agree that it would take a lot of high resistance connections to stop a 5P array.
January 17, 20242 yr 20 hours ago, uDuWaR said: I also have a King model (Axpert King II Twin 6.2 kVA) and I am experiencing a similar issue with the MPPT dropping Interesting. I think that the DSP software will be fairly similar, except for the MPPT handling hardware and firmware. Given the vastly different MPPT hardware and yet similar problems, that suggests it might well still be DSP firmware issues. It will be interesting to see what the newer firmware does. What firmware versions do you have (before and after updating)?
January 22, 20242 yr On 2024/01/17 at 3:37 AM, Coulomb said: What firmware versions do you have (before and after updating)? Hi @Coulomb Post updating my firmware (you would have seen my process I used in this thread), I beleve this has resolved my issue with the MPPT Dropping. The main cpu firmware has changed from 68.03 to 68.11
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