June 16, 20215 yr I am having same problem error code 51 in my inverter and it just got damaged. It happened when i changed charging current paramters Total PV + Utility from 20A to 30A and explicit utility charging current from 2A to 20A. There was very nominal load (160watt) runing on inverter. Both utility and pv where charging. Inverter Ratings (5KVA-48-PAR-A): Rated Current: 60A Voc: 145V My pv Voc is max 125V. ( 2 strings of 4 panels each) each panel is Voc 31. So 31x4=124v which should be fine for a pvmax 145v inverter. I am not sure why this happened because i was only runing a load of 160watt at that time. I am sure it happened on changing charging parameters.
November 13, 20214 yr On 2018/09/30 at 3:49 PM, Chris Knipe said: Hi, Do I've had my Axpert for the better part of 7, or 8 years now (when was the Eskom cockup?)... The system has about 270aH batteries (Lead Acid) maintained very well. PV is (almost) maxed out to the capabilities of the inverter. Up to today, the system has been operating flawlessly and I've not once, had one single issue.... Today in CPT, is a very warm (32C) day after a long, cold winter. I don't know whether that may be applicable. My Axpert has shut down twice, with a Error 51 (Overload/Surge), but it doesn't indicate where the the problem is. My electricity supply has surge protectors (none blown), my PV also has surge protectors (none blown, three separate strings with three separate protectors). Anyone know what the cause could be, or what I could / should be looking at? I'm not 100% but I am pulling 111V currently on the PV, and I am wondering whether the supply from the PV isn't too much for the inverter, although PWM should control that, shouldn't it? It's been so long since I had to work with these systems, ai, I forgot most of it. Any help and / or pointers would be appreciated. I don't think anything is broken, there must be a logical reason why the surges are occurring, and a logical reason how to manage it. FYI: 3 x PV Strings in parallel (3 x 320W I believe), each protected with a 10A fuses, surge protection, and properly earthed. 270aH, 48V battery bank, fuse protected Single Phase 220V AC Supply, Surge Protected, not fused. No fuses or surge protection devices triggered with any of the error 51 conditions. A simple restart of the inverter and everything works 100%. Few hours (randomly) later, error 51 would reoccur. Happened twice, hasn't happened a 3rd time yet... Any outcome/answer on error 51..overheating..solarpanels..eskom..
January 9, 20224 yr On 2020/07/02 at 8:42 AM, maxo said: Hi Coulomb All measured in- circuit first (must have some skill to know where the parts are in parallel connection, especially in case of diodes and small value resitors; or in case of BJT and resistors or chokes), but it could be done with no problems. Resistors check was done by precise multimeter with automatic range in Ohms/kOhms/MOhms range; btw diodes, zener diode, BJT, mosfets and IGBT was checked in diodes range. For ELCO's check I'm using analog (home made) ESR meter (Homo Ludens circuit), used already for a long time and have skill to work with it. I was built it with two measuring ranges (0-2 Ohm) and (0-20 Ohm), it operates at 100 kHz and is really very usefull instrument. I have also digital ESR meter (PIC chip operation), but analog indication works better for me, I have also RC3563 low ESR meter, works best on Li-ion batterys for very low internal resistance check, but it works just on 1kHz, what is a little bit low frequency for good in-circuit elco's internal resistance testing. On main board is more than one point or areas, where in circuit measuring is tricky, for me there was with great help old main board (2014 version), to check or compare measured values on it and on actual board under repair. One of such a point is D40 diode- it shows complete short on diodes range, on resistance range shows very small resistance (about 0,4 Ohms or something around), just because its wiring- after desodering and measure out of circuit shows it is OK. With great help was also partial scetches done by Coulomb and Weber published on Aeva forum and also my circuit diagram made recently on old board - like I said in previous email - will be shortly published here when finished- still working on it. Just another word about IGBT testing - in circuit is almoast immpossible except if you have another good board like I have to make comparision. Best is to desolder them out off (if you are not sure what is real) and check them out of circuit with one of quick method, methods are published on web all around- best way for me is very simple circuit with DC supply 7-15V and with few resistors and two tact switches and one led disode for visual control if IGBT works properly (on- off) check. The internal diode could be checked with no problem in-circuit too, the IGBT funcionality is best to check out of circuit like written. Last word about the board check: version 2017 was factory laquired by transparent spray, especially on back side of the main board on high-voltage part with thick layer. For in circuit check you need to use very sharp tips to come through this laquired layer and have appropriate connection with the measuring tips- it is not easy somethimes and took a lot of time and nerves. Have fun maxo Hi @maxo, Great insights on error 51 and 09 and happy you managed to revive your unit. I have an Axpert 3kVA, 24V, 80A MPPT, "branded" MPP Solar, bought in 2016. I got the same issue, error 51, reset 2 times and then inverter did not work anymore with error 09. It is only charging the batteries with the power switch in off position. I opened the unit and inspected all boards including the main board, where I think the problem is, and found no visible damage, no blown components, not even heat marks. Maybe I am lucky and the damage is not that bad. I did find some zero ohm reading in places I think it shouldn't normally be (see the pictures) If you can post the circuit diagram of your board, even if it is not finalized (and not the same model) that would still be of great help. Any ideas where to look? Thanks a lot to anyone that can help. Valentin
January 10, 20224 yr 19 hours ago, stvaly said: I have an Axpert 3kVA, 24V, 80A MPPT, "branded" MPP Solar, bought in 2016. I got the same issue, error 51, reset 2 times and then inverter did not work anymore with error 09. Fault code 09 is not a good sign. Quote It is only charging the batteries with the power switch in off position. That at least indicates that the processor is working, getting power, and is able to communicate with the SCC. Quote I did find some zero ohm reading in places I think it shouldn't normally be (see the pictures) Most of those are to be expected; they are inductors that are essentially zero ohms at DC; you won't be able to measure the resistance with a standard multimeter. Quote If you can post the circuit diagram of your board, even if it is not finalized (and not the same model) that would still be of great help. This schematic for an early 5 kVA model still needs some work, but it may help some: https://forums.aeva.asn.au/viewtopic.php?p=88434#p88434 I don't understand this last photo: where are you measuring the zero ohms? Certainly the primary of the current transformer will read zero ohms; that's the larger of the "transformers" with the yellow tape in the foreground.
January 13, 20224 yr On 2022/01/10 at 3:12 PM, Coulomb said: Fault code 09 is not a good sign. That at least indicates that the processor is working, getting power, and is able to communicate with the SCC. Most of those are to be expected; they are inductors that are essentially zero ohms at DC; you won't be able to measure the resistance with a standard multimeter. This schematic for an early 5 kVA model still needs some work, but it may help some: https://forums.aeva.asn.au/viewtopic.php?p=88434#p88434 I don't understand this last photo: where are you measuring the zero ohms? Certainly the primary of the current transformer will read zero ohms; that's the larger of the "transformers" with the yellow tape in the foreground. Hi Coulomb, Thanks a million for the schematic, will continue testing the board when I have more time. I'm getting zero ohm across the 3 components inside the pink marked area, not the inductor or transformer (I know that would measure zero with a multimeter). I think the yellow component is a capacitor, the blue a varistor for overvoltage protection, and not sure what the green one is, maybe also overvoltage protection. It just seemed odd to me to get zero across those. It might even come from somewhere else, I just did a few quick measurements and discovered that. Do you think it's possible to get 0 ohm on these components on a working board?
January 14, 20224 yr Thanks for the clarification. 1 hour ago, stvaly said: Do you think it's possible to get 0 ohm on these components on a working board? No. The yellow capacitor, and possibly the green MOV, is across the inverter output. Most likely your inverter IGBTs are shorted. Edited January 14, 20224 yr by Coulomb
January 17, 20224 yr On 2022/01/14 at 2:17 AM, Coulomb said: Thanks for the clarification. No. The yellow capacitor, and possibly the green MOV, is across the inverter output. Most likely your inverter IGBTs are shorted. You got that spot on, I measured the IGBTs and all 4 are shorted between SD. 3 of them measure ~ 50-60 ohm between GD. The good thing none of the IGBTs exploded and the damage seems minimal. I like to think it's because I have residual current protection installed before and after my inverter. But maybe it was just luck. I also measured the resistors and diodes that feed the G pins and the driver circuits, everything seems ok. I will come back with updates as I progress with the repair. Great help! Thanks!
January 18, 20224 yr Hello peole from italy with Axpert VM3 error51!!! from 3 days but I think I have resolved
January 18, 20224 yr I have an Axpert Vm3 5KW mppt 120-450V, 16 batteries of 100A AGM , PV 1500w 270Vmax. I use it in parallel to the mains, my problem started 3 days, at 12:00 12:15 PM it crashes with error 51 every day at the same time goes into error, reset works for 24 hours. I reloaded the firmware, panel control 2.61, main unit 91.20, here it is winter and the winter temperature is at 40-42 ° C I discovered that I have two batteries at 10.8 V, I disconnected them and today it did not give me plus error 51. now I have changed two batteries and tomorrow I will repeat the test
January 19, 20224 yr 11 hours ago, MARCO82TNIT said: I have an Axpert Vm3 5KW mppt 120-450V,... I reloaded the firmware, panel control 2.61, main unit 91.20, Those sound like the firmware for an Axpert Max 7.2kW. Is there a typo there? Interesting that a weak or low voltage lead acid battery module can cause fault code 51. I would never have guessed. Perhaps you would benefit from a balancing solution. Also, > the winter temperature is at 40-42 ° C Another typo? Guessing you meant °F or summer? Edited January 19, 20224 yr by Coulomb
January 20, 20224 yr On 2018/10/06 at 7:29 PM, Jaco De Jongh said: Da questo post, http://forums.aeva.asn.au/viewtopic.php?p=68258#p68258 , per favore perdonami Coulomb non sono sicuro di poter eseguire uno screenshot del tuo post. 40-42°C inside at Inverter Today error 51 with solar first , yesterday no F51 used battery recharges with photovoltaics no utility.. Without photovoltaics it works regularly, input mains works regularly If I use the mains battery charger at night it works regularly. if I use the batteries to supply the 220V the inverter works regularly. Before I ship the inverter for warranty repair, I want to understand what causes it to go wrong to help you out.
January 22, 20224 yr On 2022/01/21 at 4:03 AM, MARCO82TNIT said: Before I ship the inverter for warranty repair, I want to understand what causes it to go wrong Fault code 51 (Output Over Current or sometimes described as overload/surge) is one of the most mysterious fault codes to me. This earlier post says that they fixed it by replacing some capacitors and diodes in the gate drivers for the battery-side (MOSFET) full bridge of the DC-DC converter. To me, the DC-DC converter would be operating much the same with solar charging as with utility charging, except that utility charging is typically at night when it's cooler, and solar charging is obviously during the day when it's hotter. These 10 μF tiny multilayer ceramic capacitors do seem to be sensitive to temperature, so that part fits. 10 μF is 100x higher capacitance than the largest common ceramic capacitors (at 0.1 μF). So they have to use ceramic materials with extremely high permittivity to get the capacitance in a relatively small package (3.2 x 1.6 mm), and this seems to make them unusually susceptible to temperature and even to applied voltage.
January 22, 20224 yr yes it is a strange mistake, in conclusion: - the inverter goes into error 51 with the photovoltaic connected together with the storage with and without load at the 230V output -FV connected + mains input without batteries does not go into error 51 with and without load 230V -Fv disconnected, with accumulation connected + mains input works regularly with and without 230V load -Fv and mains input disconnected, with accumulation connected it works regularly with and without 230 V load -From Error 59 when I connect PV with inverter off, storage connected without / with grid connected, the PV string voltage was 255 Vdc Bus voltage with batteries connected on 430V and internal temperature of about 40 ° C, without batteries the voltage remains on 360-370V and internal temperature of 20 ° C
January 23, 20224 yr Today ONLY BATTERY, no grid , no PV Real Voltage battery 51V ... read ok Inverter 67V!!! real FV voltage disconnected... inverter read 612,8Vdc 6400W .. incredible!!!
February 5, 20224 yr On 2022/01/18 at 12:50 AM, stvaly said: You got that spot on, I measured the IGBTs and all 4 are shorted between SD. 3 of them measure ~ 50-60 ohm between GD. The good thing none of the IGBTs exploded and the damage seems minimal. I like to think it's because I have residual current protection installed before and after my inverter. But maybe it was just luck. I also measured the resistors and diodes that feed the G pins and the driver circuits, everything seems ok. I will come back with updates as I progress with the repair. Great help! Thanks! This evening I finished replacing the 4 IGBTs and put everything back. I was nervous getting ready to start the inverter and was ready for any outcome, including a bang 😁 To my delight, it started with no error and it works like new! Finally back! I'm so happy for this success. I'm grateful to the community for help, especially @Coulomb Many thanks!
February 8, 20224 yr the seller wrote to me that the inverter has been repaired, he sends it to me next week, last error that gave powering even with the network only, the battery voltage was high. I'll ask what pieces he changed
March 31, 20233 yr Here another F51 issue. Friends who I helped installing their system have had a VMIII 5K now for almost 2 years. A few weeks ago F51 started. They say they also saw a F59 passing by, but mostly F51. They have 2 strings of 6 330Wp panels, Vmp 37,26 Imp 8.86, so that gives 223,56V and 17,72A, which should be fine. They are off grid with 2 Pylontech US2000 batteries and the VMIII set to PYL with display firmware 2.60. They never had any AC input. On the roof I discovered that some of the MC4 connectors deteriorated. They just fell apart. We had a sahara sand storm here some months ago (think: Mad Max in real life), and everything building turned brownish-red, so there must have been a lot of iron oxide in it. My guess is that that ate the MC4 connectors. Also a Y splitter was damaged (see picture). I replaced the damaged MC4s and splitter, but F51 is still appearing. Do you think a surge/over current could have happened with these damaged connectors, causing F51? Or is that just coincidence? Any ideas? Edited March 31, 20233 yr by birdibird
March 31, 20233 yr I notified the supplier and reported it for RMA under warranty, and he said: Quote The failure 51 is usually caused by an agent external to the inverter. That's probably because you have a very high voltage or current in line with the panels. No very high voltage or current on this system. And then he continues with something which sounds bullshit to me: (Sorry about the clumsy English, it is translated Spanish to English) Quote Did you put the two strings in parallel for a 6mm cable? This is wrong for 50m Cable 10mm2 minimum Voltage drop is huge Cable overheats at peak output and inverter goes crazy That's why fault 51 goes off and protects itself And also the array of panels is badly calculated because 276 volts is too low a voltage for this inverter and the cable cross-section and the power loss is enormous. The best thing to do with these inverters is to go beyond 320 volts input from the panels. It would suit the installation correctly if you put 10 panels in series with the 6mm cable. Much better than the way you put it. The way you have it now, it is no good. Neither the cable nor the panel connection configuration because you don't reach the voltage range needed for the inverter. First the panels are 35m away, not 50m. That's a 0.84% loss (with 50m even only 1.something%), so what is he talking about. Second, where did he get the 320V story? The mppt range is 120-450V I think this is nonsense, and has also nothing to do with the F51 problem. What do you think? Edited March 31, 20233 yr by birdibird
March 31, 20233 yr Trouble shooting for error 51 How-to-check-error-code-51.pdf Edited March 31, 20233 yr by biletskiy
April 1, 20233 yr On 2023/03/31 at 10:18 AM, birdibird said: They have 2 strings of 6 330Wp panels, Vmp 37,26 Imp 8.86, so that gives 223,56V and 17,72A, which should be fine. The current is possibly a little on the high side. This model doesn't seem to have a maximum PV current (at the panels) specification; it could be as low as 18 A. If so, that's really close, and you will be getting overshoots well over that limit. But that should have nothing to do with fault code 51. My guess is that some sand/dust got into the inverter itself. On 2023/03/31 at 10:31 AM, birdibird said: Second, where did he get the 320V story? The mppt range is 120-450V The "nominal" PV voltage specification is 320 V. But as far as I know, it's pretty much meaningless. Certainly, the SCC will have to work harder to boost low panel voltages to the required bus voltage. But 12S is way too much, even with 60-cell panels. Your panels may well have triggered the problem with leakage to earth. The high voltage PV models really don't like leakage to earth. Do the inverters work with the PV completely disconnected or isolated on both poles?
April 2, 20233 yr On 2023/04/01 at 6:55 AM, Coulomb said: The current is possibly a little on the high side. This model doesn't seem to have a maximum PV current (at the panels) specification; it could be as low as 18 A. If so, that's really close, and you will be getting overshoots well over that limit. But that should have nothing to do with fault code 51. My guess is that some sand/dust got into the inverter itself. I once asked mppsolar about this. They said that on the high V models the official spec for max PV current is 18A, but that they have a margin to 21A. I have seen other setups where the max PV current in vmp 2P was more around 19A or 20A which had never any problems for years. Sand/dust you say? Hmm. I noticed in the little concrete building they build for the inverter and batteries they had quite a lot of dust. On 2023/04/01 at 6:55 AM, Coulomb said: The "nominal" PV voltage specification is 320 V. But as far as I know, it's pretty much meaningless. Certainly, the SCC will have to work harder to boost low panel voltages to the required bus voltage. But 12S is way too much, even with 60-cell panels. Your panels may well have triggered the problem with leakage to earth. The high voltage PV models really don't like leakage to earth. Do the inverters work with the PV completely disconnected or isolated on both poles? The seller actually recommended 10S instead of 6S2P, but yes, as far as I know the 320V is indeed meaningless and I have never seen it stated before anywhere except for with this seller. For now to try I asked them to disconnect 1 of the PV groups, to see what happens. You say that the damaged connectors may have triggered something? Could you explain in what way? The panels are on a concrete roof and in the fuse box they are connected to a DC SPD and then a DC MCB before going on to the inverter. The inverter works fine without errors if the panels are disconnected on only the Pylontechs. What do you mean with isolated on both poles? I got an update from them: In the evening and night they don't get any errors. It's mostly at the same time in the afternoon, especially when they switch on a heavier user like a washing machine. They mostly get F51 and sometimes F59. (So, the replacement of the mc4 plugs and Y cable doesn't make a difference) As the inverter still is in warranty, do you think they can make a warranty claim? Edited April 2, 20233 yr by birdibird
April 2, 20233 yr 3 hours ago, birdibird said: The seller actually recommended 10S instead of 6S2P, Ah, that makes more sense than 12S. But just tossing away the output of two panels is a bit steep. 3 hours ago, birdibird said: You say that the damaged connectors may have triggered something? Could you explain in what way? I see bare metal inside that damaged Y joiner. So it's not a stretch to imagine that moisture and/or conductive sand could form a weak electrical path to earth. It's known that electrical leakage to earth on these high PV voltage models can lead to excessive bus voltage. I'll admit that's not the same as overload/surge. I thought perhaps the extended period of high, possibly excessively high bus voltage might have caused some sort of permanent damage. It would be good to try 6S1P (one string) for a while just to demonstrate that this is not the issue (i.e. I expect the problem to continue). Though if it does stop, try the other string on its own. I'm thinking that there may be some sand jammed in somewhere causing a leakage to earth. However, I'll admit that the problem never occurring at night is a strike against that theory. 3 hours ago, birdibird said: As the inverter still is in warranty, do you think they can make a warranty claim? Hard to say. It still could be an issue with the panels. 3 hours ago, birdibird said: What do you mean with isolated on both poles? I mean both the PV+ and PV- terminals are disconnected from the panels. Either or both could be causing problems. That would normally be the case, or at least we have to break both poles to isolate PV in Australia.
April 2, 20233 yr 3 hours ago, birdibird said: They mostly get F51 and sometimes F59. F59 seems to be "PV voltage is over limitation". That seems strange for a 6S system.
April 2, 20233 yr 40 minutes ago, Coulomb said: I mean both the PV+ and PV- terminals are disconnected from the panels. Either or both could be causing problems. That would normally be the case, or at least we have to break both poles to isolate PV in Australia. Ah, yes. Same here, both poles are broken by the MCB.
April 14, 20233 yr @Coulomb Update: The inverter now gives F09, so it is definitely broken and needs a new motherboard. The seller keeps insisting that for 35m 17,5A 270V a 6mm2 cable is the cause of the problem. I cannot believe that and have never experienced that in all the years on any other project. (The loss is as I calculate 0,85%.) What do you guys say about this story and the cable thickness? Can that cause the inverter break?
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