October 10, 20187 yr Author HALLO MAMMMAAA!!! Testing MOSFETS... Q19,13,18,23,24,11,17,20,38,21,22,21,40,26,25,14 (left to right as you face them). ALL of them: Resistance GS: 11.7K (fine). GD 130k (manual states 250k?), DL O/L Considering I get 130k across ALL the MOSFETs and not one, I am going to assume a reading of 130k instead of 250k is sufficient Diode: SD 0.43V EXCEPT Q14 where I get a O/L This is definitely a faulty MOSFET. So MOSFETs needs to be replaced. Let's continue working our way through the service manual and see what else I can pick up. I am posting all my findings here to act as a reference to the fault(s) so that they can be discussed, and to help others with the same Error 51 condition in the hope that we can get these units replaced.
October 10, 20187 yr Author Drivers: R42, R87, R92, R92 faulty Which means we can replace all 16 resistors, and more than likely all 16 Transistors too Edited October 10, 20187 yr by Chris Knipe
October 10, 20187 yr I have a question: Why did it happen: Age? Temp? Power surges? ... could it be all three? If it is power surges then can happen again and others could also be affected in due course, maybe. Ok two: And if they are replaced, is that it or could there be more parts affected that also needs replacing later? DIY is cool but asking from a non-DIY perspective: Is it worth to fix?
October 10, 20187 yr Author Drivers: R42, R87, R92, R92 faulty Which means we can replace all 16 resistors, and more than likely all 8 Transistors too Q46, Q48, Q41, Q43 Resistance BE 26M (manual states 420k), BC 26M (manual states 420k), CE 30K (correct) Q46, Q48, Q41, Q43 Diode BE 0.6V (all fine), BC 0.6V (2 fine, 2 dead), CE (all busted) Q15, Q16, Q41, Q43 Resistance BE 26M (manual states 420k), BC (26M (manual states 420k), CE All over (should be 30K) Q15, Q16, Q41, Q43 Diode BE 0.6V (all fine), BC 0.6V (2 Fine, 2 busted), CE (all busted) Dont know why they are faulty, but the service manual seems to indicate that once they are replaced everything should be fine... Someone with a bit more knowledge should be able to explain what / why this failed, but given it's mosfets and drivers, my money would be on the fact that there was one or more massive surges that blew the mosfets, and that then caused other things to go faulty. The drivers (resistors / transistors) goes faulty when the mosfet goes, it's internal protection according to the manuals. Still testing on... Edited October 10, 20187 yr by Chris Knipe
October 10, 20187 yr 2 minutes ago, The Terrible Triplett said: Age? Temp? Power surges? Can be a combination of the three. 52 minutes ago, Chris Knipe said: So MOSFETs needs to be replaced. Internal issue? What a surprise.
October 10, 20187 yr Author 1 minute ago, Jaco de Jongh said: Internal issue? What a surprise. I know I know. You can all say "I TOLD YOU SO" right about now... Mosfets alone is going to cost me about R600.. Given all the other parts too... I'm calling it once the repair bill hits about R3K, then I must just as well buy a new inverter
October 10, 20187 yr Author BTW... Manual suggest a "Short or Explosion" as the failure status of all these components...
October 10, 20187 yr 18 minutes ago, The Terrible Triplett said: Age? Temp? Power surges? 16 minutes ago, Chris Knipe said: should be able to explain what / why this failed, The way the story normally goes. As electronics age, they deteriorate, so the components cant handle the punishment as well as before. In a lot of cases a spike or surge will hurt them, but not blow them. Components like that will normally only show under hotter conditions (higher temperatures). In short, any one of the three or any combination of the three could have caused or contributed to the current state of affairs.
October 10, 20187 yr Author Q60/Q61 Mosfets blown. I think I may just as well stop. Anything related to the MOSFETS & Drivers are dead. About to start testing the PWM controllers, and I bet there everything will test fine) Spare parts? Can one buy a new main board somewhere? Cost? Edited October 10, 20187 yr by Chris Knipe
October 10, 20187 yr Author U9 PWM CNTL dead!!!! omfg... Screw this... New main board please... anyone?
October 10, 20187 yr 2 minutes ago, Chris Knipe said: Spare parts? Can one buy a new main board somewhere? Cost? Heinz at Full Circle Solar is really clued up with the repairs on Voltronic products. I guess he is one of the best guys to speak to about spares and repairs . [email protected]011 074 4533 / 083 435 0297
October 10, 20187 yr Author Entire battery side of the main controller board is blown. Bus side components are fine.
October 10, 20187 yr Author @Jaco de Jongh Thanks for the contact details. Have sent Heinz an email, think it's better to just explore the options of an entire new main board, rather than go through a repair at this point. If the main board's price is too high, I guess it may just be better to get a new inverter completely. I'm hesitant with a repair given the significant and extensive damage to components - who knows what else (not covered in the service manuals) are in fact damaged at this stage. Will see what they come back with. So there you have it guys. Error 51... Your inverter's more than likely in a very, very bad state of affairs.
October 10, 20187 yr 7 minutes ago, Chris Knipe said: So there you have it guys. Error 51... Your inverter's more than likely in a very, very bad state of affairs. Can happen to any of us ... All MAKES of inverters. Worst is when the power comes back after a failure. Circulars went around, even from insurers, to switch everything off after the failure and wait for it to settle before switching stuff back on. And we all had a lot of failures at one stage. Not that easy with DB connected solar systems (all MAKES). They take hits when the power comes back on. Edited October 10, 20187 yr by Guest
October 10, 20187 yr 4 hours ago, Chris Knipe said: HALLO MAMMMAAA!!! Maybe, maybe not. 4 hours ago, Chris Knipe said: Testing MOSFETS... Q19,13,18,23,24,11,17,20,38,21,22,21,40,26,25,14 (left to right as you face them). ALL of them: Resistance GS: 11.7K (fine). GD 130k (manual states 250k?), DL O/L Considering I get 130k across ALL the MOSFETs and not one, I am going to assume a reading of 130k instead of 250k is sufficient Yes, this is just leakage from various components in the surrounding circuit, I suspect. Certainly nothing stands out so far as a problem. 4 hours ago, Chris Knipe said: Diode: SD 0.43V EXCEPT Q14 where I get a O/L This is definitely a faulty MOSFET. No, Q14 is directly paralleled with three others. You're likely being fooled by the tenacious conformal (some say confounding) coating. Unless there are substantial tracks blown, it's not possible for Q14 to be open circuit with its three paralleled devices not open. 4 hours ago, Chris Knipe said: I am posting all my findings here to act as a reference to the fault(s) so that they can be discussed, and to help others with the same Error 51 condition in the hope that we can get these units replaced. That's a great idea. But your interpretation of the results (entire battery side blown up) doesn't fit the facts, as far as I can see. Can I be clear on this: what was the status of the inverter (working or not) at last power down? The other thing I worry about is your comments about the fuse copping a beating with all the restarts. That seems to indicate a lack of pre-charge on the battery connections. In my opinion, whenever large capacitors are connected to a substantial voltage low impedance source (a 48 V nominal battery certainly qualifies), you need a pre-charge circuit to limit the switch-on current to something like 20 A instead of 2000 A. Big splats aren't just scary or blackening of fuse ends and fuse holders; they cause all sorts of problems with surge currents and transient voltages from stray inductances. I know it's expensive to add a DC rated contactor or switch/breaker, but to me it's just part of the cost of doing business. Sorry to be such a grouch. But it still seems to me that you could get away with just replacing four MOVs. These ones are thermal fuse protected, which I think could mean that they could look brand new, but the internal fuse could have blown. It's a pest to test those things, unfortunately.
October 10, 20187 yr 4 hours ago, Chris Knipe said: Drivers: R42, R87, R92, R92 faulty Which means we can replace all 16 resistors, and more than likely all 16 Transistors too Can you tell me how you reached that conclusion, please?
October 10, 20187 yr Author 2 minutes ago, Coulomb said: Can I be clear on this: what was the status of the inverter (working or not) at last power down? The other thing I worry about is your comments about the fuse copping a beating with all the restarts. That seems to indicate a lack of pre-charge on the battery connections. In my opinion, whenever large capacitors are connected to a substantial voltage low impedance source (a 48 V nominal battery certainly qualifies), you need a pre-charge circuit to limit the switch-on current to something like 20 A instead of 2000 A. Big splats aren't just scary or blackening of fuse ends and fuse holders; they cause all sorts of problems with surge currents and transient voltages from stray inductances. I know it's expensive to add a DC rated contactor or switch/breaker, but to me it's just part of the cost of doing business. Sorry to be such a grouch. But it still seems to me that you could get away with just replacing four MOVs. These ones are thermal fuse protected, which I think could mean that they could look brand new, but the internal fuse could have blown. It's a pest to test those things, unfortunately. State at last actual usage (with supply, load, PV & batteries) - worked, 100% except for the occasional Error 51 (2 or 3 times per day, only during day time, online during warm ambient temperatures). I am by no means an expert here either, so please rest assured your input and feedback is appreciated. Batteries - I find this strange as well. There is HUGE arching when the batteries are connected (I use an external 100A fuse for a disconnect). Even with the inverter switched off (nothing connected to supply, PV, or load), there is arching when connecting the batteries. This never used to happen before. The batteries are also EXTENSIVELY cooking, which never happened before. Yesterday, I connected batteries & PV and switched the inverter on. Supply & load was disconnected as this was still by-passed. According to the Inverter's panel, there was a load of some 300W being pulled, yet nothing was connected to the inverter at all. At about 9PM after sun set and PV didn't generate any power, I actually got battery low alarms, and the inverter shut down because the batteries was flat. So, what was pulling loads, and why did the batteries drain? MOVs... Anyway to test them? Again, I am not saying that there is / isn't anything wrong with them (I don't have the knowledge to make that call), but I also don't want to just blindly go replace things and potentially, break things even further in the process... Re Resistors & Transistors - they where tested. Some faulty, some not. I figured as they recommend in the service manual to replace all MOSFETs in the case of one being faulty, I may just as well replace all the transistors too. Transistors are cheap enough to just replace them. Given the extent of my testing though, the list of components (potentially) to replace is becoming too significant for me personally at this stage. For me faulty means not getting a reading as it is suggested in the service manual. More than that I don't know unfortunately. So if the service manual tells me I must get a SD of 0.43V on Q14, and I don't get it - I have no reason to believe other than that Q14 is faulty. Not saying that YOU are wrong of course I'm saying that if you are right, the service manuals is wrong...
October 10, 20187 yr Author Im actually also very curios, why virtually every single error condition (EXCEPT Error 51) and this includes replacing the MOVs too, is covered in the service manuals... Edited October 10, 20187 yr by Chris Knipe
October 10, 20187 yr Must say, I was reading this and thinking... there is no way all that stuff is blown and the inverter still sort of works with only the occasional error. I've looked at the service manual of that inverter, and a lot of it seems to be preliminary high-level tests for resistance levels. As an example, you cannot test a FET in circuit and conclude that GS is shorted... it might well be the driver that's shorted and not the FET. And so on and so forth...
October 10, 20187 yr Author Again I am not arguing, just stating... Page 15, in terms of testing D32/D35/D33/D34, they explicitly say that R90/R99/R94/R97 must be removed for the test (they do that for quite a few tests, granted it's all diodes that is being tested). Why state on one test that components must be removed for the test to be accurate, but they don't state it on the other tests? I know too little here other than to follow the instructions of the manual and the instructions in the manual does not state that components must be removed (yet, I know what @plonkster is saying may very well hold true with my limited understanding of micro electronics). I'm no electrical engineer though. MOVs can't be tested at all either from what I am seeing. Oh Error 51, why must you have entered my life... I'm baffled as to how few occurrences, and now little knowledge / information is out there about this specific error. It's almost like you've hit one in a million here...
October 10, 20187 yr 2 hours ago, Chris Knipe said: I'm no electrical engineer though. Neither am I, but I've had enough fun with MPPTs in prior years, on this very forum. One of them blew a driver...
October 10, 20187 yr 8 hours ago, Chris Knipe said: For me faulty means not getting a reading as it is suggested in the service manual. Updating a service manual properly is an expensive process. It seems like they handed this to a very junior engineer, perhaps even a work experience student, and said "Here, use this multimeter on these components and record the readings in this file". There doesn't seem to be any consideration of how repeatable the measurements would be. Quote So if the service manual tells me I must get a SD of 0.43V on Q14, and I don't get it - I have no reason to believe other than that Q14 is faulty. Just be aware that an open circuit reading means that it might be open circuit, or it might be particularly thick conformal coating, and you just need to push or scrape a little harder with the multimeter leads. Experience really helps here, and it's difficult to convey all the experience via a forum like this. Top marks for trying though. With the 300 W mystery load, that could fit the MOV story, except that the MOVs can only handle 1 W each continuously. 300 W into one or two of them would cause them to burn up spectacularly. So now it looks more like a measurement error. Unless you are looking at the VA screen instead of the power (Watts) screen; with no load, there is considerable apparent power (VA) running back and forth between the inverter and the large smoothing capacitor (C33 on the one I have here, a rectangular black capacitor about 50 x 40 x 30 mm). My recollection is that it's usually some 10-60 VA at no load, not 300 VA.
October 11, 20187 yr Author So spoke to Full Circle Solar as @Jaco de Jongh suggested. Except for the normal "ventilation, be sure it's grounded, surge protection, etc" something interesting came out... They had a fair amount of customers, suffering from Error 51s. ONLY during 12:00 and 13:00 (Note, they are in JHB, I am in CPT). In ALL these cases, they reduced the PV generation on the Inverter and the issue went away, immediately. Never to return. This is caused by surges on the PV side (as I have originally suspected), it is caused by surges in wattage and voltages due to extreme solar conditions. I am 6V away from Voc in a NORMAL day. On a day with extreme sun, I will MOST DEFINITELY exceed Voc. It's nothing for 9 x 300W panels, to fluctuate and generate that additional 6V and by doing so generate an overload / surge condition on the Inverter as it is exceeding the max ratings of the inverter. It also explains why it ONLY happens when it's hot, warm and sunny. Not quite sure when I'll get to this, as the re-wiring required is extensive, but I will be moving from 3x3x300W to 2x5x300W to reduce my Volts & increase my Amps on my PV supply. That should solve my issues.... There's no damage, there's nothing broken. This is WEATHER together with my PV being EXTREMELY close to Voc, and me generating too much power over PV on hot warm days for the Inverter to handle. Nothing more, nothing less. Edited October 11, 20187 yr by Chris Knipe
October 11, 20187 yr 1 hour ago, Chris Knipe said: ONLY during 12:00 and 13:00 (Note, they are in JHB, I am in CPT) That is very strange Chris, I also had a lengthy discussion with them, and our conversation went in a totally different direction. The problems they had was blown MPPT's around that time. We had a discussion of what the cause could be as they are receiving more BLOWN Axperts than normal. Their question to me was, could solar flare have any effect in this, and we discussed a few different possibilities. They did mention having to deal with error 51 in the past, and from their experience, error 51 normally shows that something internally is failing and are more than often followed by a more serious error like error 9 over a period of time. When I saw this post, I phoned them again to make sure I have my facts correct. 1 hour ago, Chris Knipe said: I am 6V away from Voc in a NORMAL day. On a day with extreme sun, I will MOST DEFINITELY exceed Voc 1 hour ago, Chris Knipe said: It also explains why it ONLY happens when it's hot, warm Chris you need to understand that heat is not good for production, the hotter it gets, the less your panels produce, in your setup it is virtually impossible to exceed your panel wattage when its hot and the panels are under load. Voltronic will definitely build in some kind of safety factor to absorb accidental VOC, it will not just blow components once it senses 146VOC, I guess it needs 10 to 15% more before you should start damaging stuff, and then there is the build n safety that I will touch later. If however it was 2 degrees outside and you experienced cloud edge effect you might exceed the wattage of your panels, but not when it is excessively hot. 1 hour ago, Chris Knipe said: There's no damage, there's nothing broken. This is WEATHER together with my PV being EXTREMELY close to Voc, and me generating too much power over PV on hot warm days for the Inverter to handle. Nothing more, nothing less. Just one question, you have never experienced similar conditions over the last 7-8 years, its only this year that the weather does this? 1 hour ago, Chris Knipe said: as the re-wiring required is extensive, but I will be moving from 3x3x300W to 2x5x300W to deduce my Volts & Amps on my PV supply. That should solve my issues.... I agree, two in series is the safer option and will take some strain/stresses of your components. It is even one of the recommendations FCS makes to all their Axpert users. --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- My last thought on this. Maybe the years of running that close to max VOC took its toll and combined with age weakened one or two components. As mentioned by a few, electronic components that is busy failing normally acts up under hotter conditions. So, now 7-8 years down the line only, because of a weakened component the Array voltage is to much for the machine to handle, and under hot conditions this component flashes over causing error. Reducing your PV array volts treats the symptoms, not the problem. Please remember Axpert didn't only create fault messages, it also gave you error messages to act as warning to warn you of conditions before it reaches Fault conditions or failures. Your inverter has these two warnings related to your suspicion. This warning tells me that The inverter firmware would stop the working of the MPPT when it detects and overload / over voltage condition, and I guess they do this to protect the other components from getting damaged. If error 51 occurred because of a true PV overload/overvoltage condition, I would at least expect one of these conditions being present in your log files before an error 51 gets issued. I truly hope you find the thing that is pestering your inverter.
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