APV

That is bad news @charlez :( If (and only if) moisture is part of the problem, it could be that the cables were not completely dry after laying on the roof. So maybe there still was some leakage in your case... I have to tie mine up like you did in any case, since rain causes my earth leakage to trip. So my system is even worse than yours :)

OK, so now there are 3 of us with the same type of installation and the same issue - I smell a rat

@rddkrn Are your connectors laying on the roof, or are they tied up?

Hallo @charlez I believe that simply lifting them from the surface of the roof with cable ties (or whatever) should be fine. It will be quite a mission for me to modify my wiring, since I have grouped the panes in a chunk of 8x2 with only a 1cm gap between them. Hopefully I can reach the cables from the lower and upper sides of the array... My problems only occur in fairly heavy rains. I use the CANADIAN SOLAR 405W SUPER HIGH POWER POLY PERC HIKU panels with MC4 connectors, so it is the same brand...

It is very likely that the panel wires get wet. The connectors between the panels are currently just lying on the roof. Even though they are supposed to be waterproof, there probably is a bit of leakage when the roof gets wet. So firstly, I shall have to try and lift the connectors off the roof, where possible. If that does not solve the problem, I guess I shall have to build a 1:1 isolation circuit myself

I have encountered another issue. Every time it rains, the earth leakage unit on my house DB trips. This morning when it did it, I measured the AC voltage between ground and the PV input - 130VAC!!!! The source of the floating voltage is the inverter, not the panels. Why would this happen? I thought the PV input was 100% isolated from the rest of the circuit!!! This is probably part of my problems with the Error 08 issue...

I can confirm that my unit also shutdown in the early morning hours. It was raining then. I disconnected the solar panels and it did not happen again (as would normally be the case)

I don't think you should spend time on increasing the time to 200ms. The fact that the bus voltage goes so high, is by itself the problem. So whether it goes above 500V for 1ms or 400ms, is irrelevant. I feel safer with the system shutting down rapidly when the fault occurs (even though it should not occur at all). But thank you for the offer

OK, point taken Thank you for all the feedback - much appreciated. Then I guess we have to look at Voltronics for the proper solution

Like in physically disconnected, or only when it is dark? In my case, it is dark and the inverter is in bypass mode when Error 08 occurs. Only by physically disconnecting the panels, was I able to get the bus voltage to return to normal...

I would like to hear if the following works for other people. When error 08 appears, disconnect the solar panels. Hopefully you have isolator boxes installed between the panels and inverter!!! It worked for me - the bus voltage dropped to its normal level of about 372V in a matter of 30 seconds. If it works for you too, I think a quick fix would be to connect the panels via a diode. I am waiting for the next cloudy day to test my theory... I know it is not the "proper" solution, but what the heck. If it solves my problem, it is a quick, effective way to prevent a power disruption from a device that is suppose to prevent power loss Even if (big if) Voltronic fixes the problem, I don't think it is too bad an idea. You do not even have to open the inverter to apply the modification. All of this is dependant on positive feedback , of course...

When the panels are disconnected in this state, there is a voltage of about 50V at the panel connector on the inverter. I am going to insert a diode between the panels and the inverter and see if it makes any difference...

Here is something extremely interesting!!! The inverter currently is in its bad mood. When you switch it off at the bottom, the bus voltage goes to zero. When you switch it on again, the voltage quickly goes to 380V and then rises quite fast until it trips. Out of sheer curiosity / desperation, I switched off the solar panels. The bus voltage dropped to 380V in a matter of 30s!!! Now remember - the unit is in bypass. It is pitch dark outside. I have measured the solar panel input - just about 0V. So why the heck would removing the panels, "solve" the problem???

It is a pity the Service Manual does not provide the circuit diagram - it would be so helpful (for me at least)...

Yes, mine did it as well. At 19h00! Around 18h20 it switched to bypass (as normal). It was raining all afternoon, with an overcast morning. I did try killing the soft start oscillator - however that kills the output as well! So unfortunately stopping the oscillator is not an option. I did oscilloscope traces on the control pin (from the CPU) of the soft start circuit when the problem was absent, as well as now., there is no difference. The pin floats high in both cases. So I guess I must start looking elsewhere for the problem. As a final test, I am going to compare the waveforms of the soft start MOSFET in the two cases. Just to be 100% that it is not the soft start circuit causing the bus voltage to go so high...

Just for interest sake, what are you using to convert the HEX code to some readable form?

Sadly, the problem reoccurred tonight after a cloudy day! I guess @BvR will have to take it up with Voltronic again

@Charlez: Did you use a multimeter to check that you made the correct connections on your RS232 converter? Based on your initial post, you need to have connectivity as follows: USB-RS232 RJ45 => PIP RJ45 5 => 8 3 => 1 6 => 2 Remember to align the PIP RJ45 as in my photo - it should just work. If it doesn't, try swopping 3 and 6 of the USB converter. Also when I look at your photo of your keystone conversion, it does not look right. Use a multimeter to verify that 3 and 6 of the RJ45 goes to the correct pins on the keystone...

Also RS485 is a differential mode protocol (no ground), while RS232 is relative to ground...

No, you cannot mix RS485 and RS232. Different voltage levels...

I presume watchpower is working now. I am impressed to see that you are using a keystone to modify the pinout! I actually wanted to suggest that (instead of cutting the cable).

If you are willing / able to cut off the RJ45 connector and crimp your own RJ45 connector onto the cable, it will work, I believe. I have done that with my USB-RS232 adapter from Banggood....

Great work BvR! I don't know how you managed to communicate with Voltronic, but I am very impressed! So now my inverter is running 7.80. We now have to wait for a cloudy day to see if the issue is resolved....

On 2019/12/18 at 2:00 PM, APV said: The voltage differs by 1-2V between my multimeter and what the script says... The bus voltage is changing very slowly, only by 10V per hour and not by 10V per socond as you wrote. So yes - it charges very quickly to 380V, and then it starts creeping. Since the unit is in bypass and it is at night, what else can cause the bus voltage to rise than the soft start oscillator? Last night when I experienced the problem, I just hit the panic button and the unit did not shutdown again. I shall delve deeper into the circuit, since the partial circuit diagrams that you have drawn up, are not up to date - - at least the component numbers have changed. They do give me a good idea of how things interact, though...