February 17, 20206 yr On 2019/12/31 at 1:29 PM, Oros said: What i have seen is on the tag of the inverter it shows Max. Solar Voltage (VOC): 115 VDC I just noticed that at least some new inverters are shipping with a Vmp figure, instead of the more useful Voc figure. And it also happens to be 115 VDC. My guess is that it makes them look more like they are Extra Low Voltage compliant (under 120 Vdc) so they don't need insulation monitoring in many jurisdictions. It doesn't explain your problem, however.
March 6, 20206 yr Hi guys - I'm experiencing the same problem. Solar PV stops supporting the load and does not charge the battery around 10:30 onwards. Voltex Axpert MKS 5kw inverter. System PV config is 2S3P - 380w PV panels. - Most PV voltage noted on the display is 91V.
March 6, 20206 yr Until - Sun goes down then it changes to Utility. Problem is should load shedding come soon after then the battery will be low.
August 26, 20205 yr That's weird. When I read trough this topic I thought that I found the answer to my problem that is the same: "The problem remains that when battery is full and reaches around 52V the inverter first reduces charging current, then switches the PVs off and on again several times in some 15 seconds intervals. It does this for a while and then it remains in PV off condition until the battery reaches approx 90% of charge. I vent trough the manual over and over again but cannot find any clue." Now that Oros writes that it occurs even at 80V it tells me that this is not a PV over voltage problem. So what is it? I suspect a firmware problem. My firmware is: U1 74 40, U2 04 12. Does anyone have a clue? By the way, in the attempt to analyze the problem with my laptop I connected the battery monitoring USB to RS232 cable to the battery and at the same time the USB cable to the inverter. That damaged my inverter communication board. Apparently there is a ground potential difference. So I advise never to do that. I now have to get a new board. Luckily it did not any harm to the battery communication interface nor to the laptop. Edited August 26, 20205 yr by Beat
October 11, 20205 yr On 2020/08/26 at 2:17 PM, Beat said: The problem remains that when battery is full and reaches around 52V the inverter first reduces charging current, then switches the PVs off and on again several times in some 15 seconds intervals. It does this for a while and then it remains in PV off condition until the battery reaches approx 90% of charge. I vent trough the manual over and over again but cannot find any clue." It is even worse. After the PV were cut off they remained disconnected until the next morning at sunrise. But I found the solution. I followed @Coulomb's recommendation in another thread to set 26 the bulk charging voltage to 52.2V and 27 floating voltage to 52.5V. I monitor the inverter thanks the remote control pane and the battery BMS with the RS232 cable on my laptop with PbmTools in my office. When coming up with the charge of a sunny day it slightly overshoots and then gradually comes down to 52.5V. It remains there by adjusting the PV input to what is needed for the actual load. Battery input remains at 0A and the BMS shows SOC remaining at 100%. When increasing the load, IE the vacuum cleaner or kettle, it adjusts the PV input to satisfy the load, provided the PV input power is available. That is exactly the behavior I expect the inverter to do. The PV voltage at full power is approx 124V. When power is reduced it rises to approx 129V. That is well below 1he 145V OCV limit according to specs. A word to measuring values. I read different voltages between the battery voltage given by the inverter and the values displayed at the BMS of the 3 packs. This is physically impossible since they are interconnected with 25mm2 cables and there is no current. The problem lies in the measuring circuits. First there is the inaccuracy of the analog voltage divider with resistors and then the possible inaccuracy of the A/D converter. Therefor the display of 4 to 5 digits is absolute nonsense if already the second digit is doubtful. The same goes for the digital multi meters. I got 2 of them. One of them displays IE 51.7V the other 52.7V at the same terminals. So don't believe the 3rd and 4th digit on your meter, its nonsense. The resolution (last digit) of a display has nothing to do with the accuracy of a meter. I have professionally worked with metreology (measuring technology), I know what I'm talking about. The main challenge and bottom line of metreology is to know how much error you may have in your measuring result. Edited October 11, 20205 yr by Beat
October 12, 20205 yr 18 hours ago, DaveSA said: Never heard of this before - can you please elaborate - or do you mean metrology? Where you are right you are right. That comes out when writing far from home in a foreign language. Who ever finds an error in my writing may keep it. Anything to the issue? Edited October 12, 20205 yr by Beat
April 3, 20224 yr Good Day My inverter stated to act up this Morning. I noticed that the inverter is displaying much higher voltage than what the PV is pushing out. I then connected just 1 panel which is 48 volts I noticed Inverter displays around 80..if I connect 2 panels the inverter solar voltage goes over the 145Volts and cuts out the solar charging.. I measured the voltage from solar and its not the same as what the inverter is displaying. Please help...
April 3, 20224 yr Voltage from PV Good Day My inverter stated to act up this Morning. I noticed that the inverter is displaying much higher voltage than what the PV is pushing out. I then connected just 1 panel which is 48 volts I noticed Inverter displays around 80..if I connect 2 panels the inverter solar voltage goes over the 145Volts and cuts out the solar charging.. I measured the voltage from solar with multi meter and its not the same as what the inverter is displaying. Please help...
April 4, 20224 yr 13 hours ago, Brian Chetty said: I measured the voltage from solar and its not the same as what the inverter is displaying. Then your Solar Charge Controller is faulty. Have it fixed under warranty, get it repaired, or repair it yourself. It's likely to be one of four SMD resistors, worth about US1¢ each. See this post. Edit: the above assumes that you have a 145 V max Solar Charge Controller, as per the subject of this topic. If you have a 450+ V max SCC, then it's probably different. Edited April 4, 20224 yr by Coulomb
April 4, 20224 yr Thank you Columb Can you please send me a link if you have or know of.. how to disassemble axpert inverter. And yes 145V max controller. Thank you very much Columb. I'm going to attempt to repair myself.
April 4, 20224 yr 17 minutes ago, Brian Chetty said: Can you please send me a link if you have or know of.. how to disassemble axpert inverter. My disassembly/assembly instructions to remove the main board. But you likely won't need to remove that much. The service manual: Edited April 4, 20224 yr by Coulomb
April 5, 20224 yr Hi Columb My main board seems different from the pic you sent to me. Even the resistors are numbered different. See the picture attached. I'm not sure if the 4 resistors are the voltage divider circuit. Please help
April 6, 20224 yr 13 hours ago, Brian Chetty said: My main board seems different from the pic you sent to me. Sorry, I did not make myself clear. These PV measurement resistors are on a separate PCB where the MPPT lives; follow the PV in connector. Usually the SCC board is on top as you open the case, or sometimes on its side right at the top. You do have an MKS model, right?
April 6, 20224 yr Yes its Mks. Will the resistors be under the board? Because theres something preventing the board from lifting up after I removed most of the screws.
April 6, 20224 yr 4 hours ago, Brian Chetty said: Will the resistors be under the board That is the SCC board, so hopefully yes. But that's the old style SCC, so it may not be exactly the same. 2 hours ago, Brian Chetty said: Maybe a circuit diagram will help if you have one please https://forums.aeva.asn.au/viewtopic.php?p=89289#p89289 It looks like the parts designators (like U1) may not be the same between the two models of SCC, sadly. Until this year, there were no SCC partial schematic traces at all. Though perhaps the circuit on that daughter board in your second photo may not exist in the newer models. Edited April 6, 20224 yr by Coulomb
April 6, 20224 yr I need to locate the circuit to determine if resistors are blown or faulty. Can it be just a software Problem Columb?
April 7, 20224 yr 13 hours ago, Brian Chetty said: I need to locate the circuit to determine if resistors are blown or faulty. It appears to be a rather different circuit to the one I traced. But my trace is the best you'll find, I suggest. 13 hours ago, Brian Chetty said: Can it be just a software Problem Coulomb? I very much doubt it. I'd check the 200 kΩ resistors outlined in red, and possibly the ones in yellow. The board looks very dusty; maybe if/when the dust gets wet it conducts across the high valued resistors? So it might be worth cleaning up the board, and spraying that area with PCB conformal coating. But wait till you've fixed it for the coating. Edit: as a point of interest, what do the two 2-pin green terminal blocks in the corner connect to, if anything? Edited April 7, 20224 yr by Coulomb
April 7, 20224 yr Hi Columb I found a discrepancy in the R130 and R140 resistors R130 measures 0.226 R140 measures. 067 Yet both resistors are the same. Could this mean a Problem with resistors? Also the board is not dusty..it seems like the coating has faded.
April 7, 20224 yr 5 hours ago, Brian Chetty said: R130 measures 0.226 R140 measures. 067 Yet both resistors are the same. Could this mean a Problem with resistors? It could be, but desolder them and measure them out of circuit to be sure. There are other components that could affect the reading when in-circuit. They should both be 330 kΩ (you didn't mention any k or M with your readings), which sounds about right for the measurement circuit. As does the two tracks that carefully parallel each other; that's commonly done to minimise induced voltage differences. This could be the circuit that measures the battery voltage, but looking at the PCB traces, it seems more likely to be the measurement for the PV voltage. I think you're getting warmer.
April 8, 20224 yr Hello Columb Yes the resistors measured in kΩ I took the R140 out of the circuit and it measured 330 kΩ do you think its necessary to remove other resistors and measure or rather look elsewhere for a Problem?
April 8, 20224 yr Just now, Brian Chetty said: Hi Columb I took out R130 and found it to also be 330k ohms Is it worth taking out the others that measures 330k ohms in line?
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