Chris Knipe

Well everything is now taken apart and laying all over the place... No visible damage anywhere... Not a MOV, not a mosfet, not a cap, nudda. No smell of burning. Hardly even any dust. Everything for a lack of a better word, looks brand new...

Still busy with disassembly currently and working my way through the service manual to test things. The amount of test equipment I have is very limited unfortunately. Thus far, I do not see anything spectacular and/or obviously wrong. Its most certainly not heat/dust, the inverter's cleaner than my kettle TBH. Only once the main board is out, will you get to the nice stuff (drivers, mosfets, etc).

Main board MOVs

Hate to say this guys... MOVs look brand new. There's hardly even any dust in the unit. Even the fans are clean. 2 MOVs on the main board close to the power out, and 2 MOVs on the AC Input directly, all 4 looks brand new. I don't see any visible burning on any components for that matter. The entire internals of the unit looks brand new.

Had a look now yes. I only have transformers here (other than my clamp on), nothing for DC Anyways, will undo the bypass in an hour or so, and then I guess we wait for the next warm day....

That's more than likely the issue then. I was also wondering how a clamp-on would read DC current. Thanks for clarifying Jaco.

Just an FYI as well... Generally I wouldn't be worried but it may be applicable here now. Inverter's batteries and PV connected. No supply, no load. Almost 700W coming in over the PV. Batteries are fully charged at 58.2V (the clampon says 1.1A current, not sure how accurate that is), but are cooking - quite a lot. Never used to cook so badly. Either way, not sure where that energy from the PV is going to right now... Program 02 (Max charging current), is and was at 20A.

Now 40A to 80A sounds reasonable to me in terms of a surge and/or over current. Any idea of where we are talking here in terms of the event, or could this be on the supply, load, battery and/or PV? I will double check this, but I think I was on 80A for a total current, and I brought this down to 40A after my firmware updates - will double check it. I don't really monitor the inverter - it's something that always got a "back seat" and needless to say it's never been done. The only thing I have is WatchPower (I can prob. get something organized for ICC too). Let me get everything back up and running, and I'll see about leaving my laptop connected to it during the day, with the hopes that we can get a trip. Then at least we have something to look at in terms of data values up to the event occurring. I just don't think PowerWatch monitor the temps. From what I remember, touching the heatsinks at the top it wasn't untouchable hot, but it was definitely > 60C - that's the actual outside part of the heatsinks. Loads of the inverter is in the 700VA region, so not a lot. It's just strange as my input & output on the inverter is protected by 20A breakers. I'm really, really surprised that I am not getting a trip before the inverter goes to throw it's little fit. Again, why I am still leaning PV. Let me get some data, let me get a re-occurrence and let's see if there's anything that can be picked up in the data I have / can get. If we can narrow it down to a couple of components, one can always as you suggested replace those components to just be on the safe side, and see how things go from there. What you are saying seems plausible enough, even so that it can verify my story that it only happens on warm, hot days...

I do. That's not the point.

Well for me on good days, the Inverter will trip with a Error 51, 2 to 3 times a day - so yes, it's a big one for me. I most certainly don't want to loose power that amount of times per day, and then having to go through the manual and exhaustive process of disconnecting *all* power (incl. batteries) from the Inverter to start it up again, only to have it trip again after a few hours is very, very troublesome. This is just as damaging to equipment IMHO. So IF the supply is the cause then there's three things that can be done: 1) The Axpert's firmware needs to be fixed. A surge on input power should result in a TEMPORARY error condition, not a permanent one (i.e. in an ideal world, the Inverter should recover automatically). Frankly speaking, the Inverter should disconnect the mains supply and run off batteries / PV, not go ape sh!t (Error 51) and power off everything. That is the real problem, and this is where it should be fixed IMHO. 2) A small on-line UPS in front of the Inverter to continue supplying power to the Inverter in the event that Eskom goes crazy (6KVA or so, with maybe 5 minutes run time?). This should provide a stable supply to the Inverter and thus prevent the Error 51 from occurring (again assuming the surge is on the supply side and therefore the cause of the Error 51). 3) Just move off the grid, and get it over and done with already (in planning TBH). Given that I want to drastically increase my system and move off grid in any case, I doubt the costs for a UPS will be justified at this stage. IMHO this is a issue in firmware, and should be fixed in firmware. I do know and realize however, good luck with that one. It's not going to happen.

Ok, Will put the inverter back into service today and see whether the issue then persists or not. That being said... Whatever Eskom did, an error 51 is very, very bad MOJO. As I said, you even need to disconnect batteries to get the Inverter to restart. How / What can one do to prevent these surges entering the Inverter and thus causing the error condition? I do already have surge protection devices, but they obviously don't detect this as none of them blew. Knowing what causes the problem is half of the problem solved, the other half, is keeping my Inverter powered, as restarting is a huge PITA.

Doesn't restart on a 51... Tried that already. 51 needs ALL power removed (even batteries) in order to get the inverter started again. It's a nasty error to have. My poor battery fuse's contacts are so burned I would more than likely need to replace the fuse by the time that this is finished.

Hi Chris, Yes Cape Town... I'm in Bothasig (Milnerton / Panorama / Welgelegen area). Eskom supply, not CoCT. That, is VERY helpful now indeed... Have you found out anything useful about this? What are the options? Just to restart the inverter every single time, or did you actually start to replace units? Sorry guys, I pulled an all nighter last night with some other stuff that I was busy with, so didn't get the time today as I hoped to get into the unit and see what's going on inside. Will try to do so on Monday.

@plonkster, great idea - thank you. Will give it a go tomorrow as well

The thing is, without knowing what causes, and what happens when a error 51 is triggered, I don't think anyone is going to know what the problem is. If it is the battery current sensor (and heaving forbid, why can't it be the PV current sensor too for that matter), why does it only occur during day time, under heavy sunlight? Why, absolutely never ever at night (for argument's sake). Why only between +- 11AM and 3PM on excessively warm (30C+) days? If this was battery related the fault condition should occur at any time, day or night... That's just what makes logically sense to me, and that is why I am hammering on PV, instead of Inverter. Hypothetically speaking (again, we wont know the answer as we cant reproduce the error on demand), but it could be the inverter's own internal temperature causing the sensor(s) to go way wire? Every time I get to the inverter to restart it for example, fans are ramming air as fast and loudly as possible. Now, this COULD be because the inverter overheated, or it could be a result of the error whereby the inverter after the error occurred, increase the fan speed to max. The fact is, we simply do not know. I don't think any one knows. Not you, not I, not @Coulomb, and I doubt a reseller / distributor will know either. I know that much, the one or two resellers / distributors I know in Cape Town, I will be wasting my time, money, and energy to go to them for assistance. It's a bit late now, but I think first things first I'm opening the Inverter tomorrow to inspect for visible damage, and failing that I will try to put it to the test without PV for a while to see if the error reoccurs. At least then, the problem can be pin pointed and it can be said with surety it is SOMETHING on the PV side, or it isn't.

Yup. I've read it all. And the second post I posted a link to, actually states that the problem did NOT re-occur when the PV was disconnected. Going to try run a few days / weeks without PV and see what happens (not that doing that will solve anything as it defeats the whole purpose)... At the end of the day, regardless of what the issue / cause, it does look like a new inverter will need to be purchased at the end of the day. No point in continuing here with the he said / she said thing... Fact is, no one knows definitively what the cause is, and no one knows definitively what the resolution is. We can sit here and speculate and argue until kingdom come, but it ain't going to help anyone.

https://forums.aeva.asn.au/viewtopic.php?t=4332&start=1600#p64122 Assuming that there aren't such currents about, even for short periods of time, the fault would seem to be associated with that current measurement. So some current shunt (which may be an area of printed circuit trackwork), or filter components associated with that measurement. Likely there is also an op-amp to amplify the small shunt voltages to the three volts or so that represent full scale on the DSP analogue inputs. Any components around this op-amp could cause such trouble. --- @Coulomb Your own words... https://forums.aeva.asn.au/viewtopic.php?t=4332&start=1600#p64350 I have a MPP Solar branded 4048 with an Error 51, for me it must be related to PV input current - as the error doesnt re-occur with PV input switched off, but all other connections active. (and now re-occurs within an hour if PV input is on, even with half the panels disabled)My setup is 2x 3KW arrays of PV connected to 2x parallel PIP-4048MS into 24x 2v 800AH SLA batteries. --- Pretty much also maxed out like me. Think I'm going to remove my PV from the Inverter and see whether the problem persists over a period of a day or three, and then gradually bring PV back. Long and short of this, we can BOTH be right, we can BOTH be wrong. It's a very rare error (from what I can gather), and there isn't a lot of information available about it. So yes, the idea with me coming here was to try and pick the brains of those that may know just that little bit more than me... Nothing more, nothing less. Don't mean any harm or foul.

Jaco, Not wanting to argue with you, but I've got the service manuals here too. Not even the service manuals, have any reference to the Error 51. Taking it in to the supplier (out of warrantee too, might I add), they aren't going to do jack because the manuals don't tell them what to do. The fault is also VERY intermittent, and we all know the inverter is just going to be tested, after which it's going to be "oh there's nothing wrong with it." We all know how this works, especially in South Africa... If I have to buy a new unit, then everything is just frankly going to be placed on hold until I have time and money to upgrade the entire system and go off-grid (Eskom is making that SO easy these days). 13 & 14 that you posted above, is an Error condition. 51 that I am talking about, is a Fault condition. I hear what you are saying however. Surges (and especially Overloads), comes from somewhere. They don't magically invent themselves. Something is causing, and triggering this. No, I'm sure no one would deliberately exceed Voc, and sorry if it came out that way. However, there must be someone that has previously (whether deliberately, or by accident) exceeded Voc? And what happened in those cases? As you say yes, I can (and more than likely will) re-wire things myself and see whether the problem persists or not. One of the reasons one comes to a forum (and the benefits thereof), is to find out whether someone ELSE experienced something similar or not, and whether there is meaningful inputs that can be delivered. I guess, that is obviously not the case. No worries then... You and I aren't going to get anywhere TBH as you've pretty much up your mind it's the inverter, and I've pretty much made up my mind it isn't. So unless there is someone else with some inputs, that's it then I suppose. No point in going around in circles.

3 x 3 Strings 2 x 5 Strings PV Watts 2700W 3000W PV Watts (Hot) 2580W 2867W Voc 134V 90V Vmp 110V 73V PV Current 24.6A 41.0A Voc (Cold) 140V 93V Vmp (Cold) 116V 77V Inverter Ratings (5KVA-48-PAR-A): Rated Current: 60A Voc: 145V I am thus very, very close to max with a 3 x 3 configuration. A 2 x 5 not only gives me an additional 300W, but the numbers are much further from the max ratings than with a 3 x 3 configuration. Oh choices, choices (and might I add, I feel like an idiot for not realizing this when I did the initial installations).

Hi Guys, As summer is starting, it's now starting to happen more and more - so much so that my Inverter is currently switched off, and in bypass (tripped 3 times yesterday, and after firmware upgrades it also tripped once today which prompted me to for now, bypass). I am drawing close to a conclusion however I think, and I am FAR from convinced that there is any malfunction and/or damage to my Inverter. The Overload/Surge isn't caused by the load. I've tested this and by putting on excessive load on the Inverter, I get the appropriate fault code 4, and the Inverter correctly goes into bypass. This leaves me with one possibility... The PV power coming into the Inverter. I remember from the past when I did the installation, I am VERY close to the maximum in terms of PV that the Inverter can handle. I also observe these overload faults only during times when there are exceptional sunlight (extremely warm / sunny days). I have a 3 x 3 configuration, with the old ReneSola Virtus II 300W panels (http://www.renesola.com/file/Global/product/pdf/Virtus II 305-320(4035) 4BB 1000V US 1606.pdf). Plugging these numbers into @Chris Hobson 's PV String excel spreadsheet, I exceed Cold Voc and Cold VMP. Inverter and MPPT Voc is also exceeded according to the spreadsheet. 1) Has anyone here any experience in terms of what precisely the Axperts do when/when the PV Input is exceeded? Does it by any chance, generate a error 51? Can anyone test this perhaps, and confirm? We all "assume" the overload condition is related to the load, but I am (and enlighten me here please) assuming that the overload is being caused by PV input. This also means then that the fuses that I have on my PV strings, are too big and aren't providing the required protection quick enough / at the low enough rate to prevent it from exceeding Voc to the Inverter. 3) As things age (specifically PV), what happens in terms of power generation on aged PV panels, vs. new PV panels? Could the fact that my panels are a bit older now mean that they provide less stable power to the Axpert, and that these fluctuations from time to time, now start to exceed Voc more than what the Inverter would like? Again, I can understand the Inverter going into an error condition (assuming error 51) when such an overload occurs, but to date (and from what I could google), there's very little if anything, confirming what precisely the error 51 is referring to technically. 2) If my assumptions here is correct, instead of going 3 x 3, I should (theoretically) be OK to go with a 5 x 2 configuration (I have one additional spare panel sitting in my wendy house waiting for better days). Before I go down this route to rewire / reconfigure everything however, I would appreciate it if someone can please just double check the math and confirm my findings - especially in terms of what the Axpert does in an overload on the PV side. I am possibly asking a lot here, but yes. I am asking someone to exceed Voc on their inverter and confirm whether they get an Error 51 or not. I can now that I think about it, maybe run in 2 x3 for a few days, and see if the problem persists. That's a easy matter of just removing a fuse temporarily. Whilst I am not qualified per say, I do have a fairly decent understanding of what is going on here and what everything means and does. By all means, there's no need to handle me (or the situation) with baby gloves. I am FAR from convinced the error is a faulty inverter, and I am much more likely to buy into the suggestion of a overload being created / caused by circumstances (such as sunlight / PV). I am unfortunately, one of those people that needs a sound technical explanation before just "accepting" something and I am here searching for an explanation as to what is happening, and why. Some assistance please, and let's see if we can get to the bottom of this.

Coulomb, Would you still not recommend upgrading SCC firmware in the event that it is very old? I'm on 1.24 currently. Main has successfully been upgraded to 72.40.

Touch wood... Hasn't happened again since the 2nd trip (+-2PM local). If one can only find out WHERE the over current / surge occurred or came from, then at least it gives some indication of where to look. Unless of course it's internal to the unit. Given the inverter isn't under significant load and properly earthed, I doubt any damage to the inverter itself TBH. And thank you Jaco. Significant planing and protection went into the designing of the system and it only run on batteries when needed (no PV nor supply available). So my cycles are really limited. Day time my load is from PV completely, night time it's back to Eishkom keeping the batteries on standby only to be used in the case of a power failure. After 7/8 years, I still get a solid 2 to 3 hours run-time on my lead acids, just as the day when I put them in, and what I planned for (load shedding). Maybe next year or the year after, I think it's time for some upgrades and keep the grid purely for a standby.

Load on the inverter is also only at +- 20% / 25%. Very light system.

Hi, 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...