Power-One solar Inverter driving me NUTS!!!

[sam_sam_sam]

I tested between the first and third legs in my photo. Here are the results.

500vdc test

#1
175 mOhms

#2
205 mOhms

#3
215 mOhms

#4
239 mOhms

Did you do the test procedure that is outlined in this maintenance manual
Did you follow it exactly or did you deviate from what they have and if you did please explain how you did it differently
Also if you did run the test as they outlined in the manual what were your results for each section of tests
https://www.badcaps.net/filedata/fetch?id=3153508

[CapLeaker]

I tested between the first and third legs in my photo. Here are the results.

500vdc test

#1
175 mOhms

#2
205 mOhms

#3
215 mOhms

#4
239 mOhms

I also tested the two blue ones on the AC side and those tested over 4000 mOhms. (full scale on megger)

Not sure what these results mean. Could all 4 of them be bad?

I hope you mean MOhm not mOhm. There is a huge difference between Mega and Milli

See, MOVs degrade with time and how often the get zapped. The insulation layer will break down each time it gets hit, to a point of leaking or total failure (basically a short). A 175 Mega Ohms is not a failure, but it's getting time to change it out. All depends on what the rating of this MOV is and how much voltage you use with the Megger,
Let's say you hit a 375V MOV with 500V from the Megger, it will hurt the MOV each time you press the test button.

[mitsu2k]

Did you do the test procedure that is outlined in this maintenance manual
Did you follow it exactly or did you deviate from what they have and if you did please explain how you did it differently
Also if you did run the test as they outlined in the manual what were your results for each section of tests
https://www.badcaps.net/filedata/fetch?id=3153508

I have not seen any test in any maintenance manual. Where are you seeing this?

[mitsu2k]

I hope you mean MOhm not mOhm. There is a huge difference between Mega and Milli

Yes I meant MegaOhms

[petehall347]

troubleshooting is page 49 onwards

[mitsu2k]

troubleshooting is page 49 onwards

OK I think I know what you are referring to now. Please see attached. This is the only test that I can see that would be relevant. And I did perform this test in the following manner:

tested between positive and earth ground and got over 50 MegaOhms.

got approximately the same results from negative to earth ground.

I did not short the positive and negative together because it was daytime and I didn't think that would be a good idea being that there's about 256 V there. However, I wouldn't expect to see any different results if I shorted them being that they were both over 50 mega anyway. I suppose I can do this test at night, but I am just afraid of blowing the diodes on the panels and I don't really want to go up on the roof being that I am afraid of heights

[mitsu2k]

from what i can make out its behaving correctly its only the "A" models that dont halt at this fault . unless yours is an "A" model

HI Pete, I now know what you are talking about "A" models. Mine is not an "A" model. I found the manual that you must have been looking at. It appears that these have a built in Arc detection feature as well as some other features. For example, the "Autotest" feature is non existent in my inverter. I even looked under the service menu. I was able to find a key generator in order to access this menu.

[mitsu2k]

Ok I did the test outlined in the manual. (Positive shorted to Negative) at 250v on the megger to earth ground.

result= >4000 MegaOhms on the megger (full scale). All good here.

[CapLeaker]

Yours isn't an A model. It doesn't have that fat ass clamp contraption. When you hook that inverter back up to test, you put one or both strings to it? Are you using both DC ports? The solar panels face all in the same direction?

[mitsu2k]

Yours isn't an A model. It doesn't have that fat ass clamp contraption. When you hook that inverter back up to test, you put one or both strings to it? Are you using both DC ports? The solar panels face all in the same direction?

I only have one string. All panels face the same direction. I am using only one DC port but I have tried connecting to the second one as well, and got the same results

[sam_sam_sam]

I would mega ohm the cables from the solar panels to the inverter with out the cable being attached to the solar panels or the inverter especially if the positive and negative cables are connected to together as one cable run and or are in conduit because I ran into a situation where water had introduced into the installation of wires and were shorting out in the conduit so do not rule this one out I use a mega ohm tester to figure out why this device was blowing fuses ( how you test for this is you have one meter lead on positive wire and the other meter lead on the negative wire )

On the same note are you using outside rated cable that you are using for the wiring from the solar panels to the inverter if not you should be and should be outside rated conduit or if I was doing this I would be doing it this way

Your results should be the highest mega ohm reading that the meter ohm meter has and any thing else would be suspicious at least to me it would be or you have something wrong with inverter showing a voltage leaking situation

[CapLeaker]

I did notice that there is a switch on your inverter, next to the AC connection. That is to pair or not to pair them DC inputs. I think the switch isn't set for them 2 DC ports as paired. Also there support to be a jumper between the 2 DC ports going from positive to positive and negative to negative. Putting the inverter on the DC port into paired, supposed to handle more current or something. Can't remember. Got to read that manual again.

[petehall347]

what is the history of this thing ? like did it work then suddenly this fault ? any other factors that may have happened just prior to this particular fault ?

[mitsu2k]

I would mega ohm the cables from the solar panels to the inverter with out the cable being attached to the solar panels or the inverter especially if the positive and negative cables are connected to together as one cable run and or are in conduit because I ran into a situation where water had introduced into the installation of wires and were shorting out in the conduit so do not rule this one out I use a mega ohm tester to figure out why this device was blowing fuses ( how you test for this is you have one meter lead on positive wire and the other meter lead on the negative wire )

On the same note are you using outside rated cable that you are using for the wiring from the solar panels to the inverter if not you should be and should be outside rated conduit or if I was doing this I would be doing it this way

Your results should be the highest mega ohm reading that the meter ohm meter has and any thing else would be suspicious at least to me it would be or you have something wrong with inverter showing a voltage leaking situation

SAM, this is good thinking about wires shorting out inside the conduit. I do not think this will be the case but I will check it at night. It may shed light on that small transient voltage either way.. They are coming through my attic in a flex conduit. 12awg I believe. I have not seen any signs of water or moisture when I went up in the attic. The panels were installed by the builder or builder's contractor when the house was built so the wiring should all be the proper type there..

[mitsu2k]

I did notice that there is a switch on your inverter, next to the AC connection. That is to pair or not to pair them DC inputs. I think the switch isn't set for them 2 DC ports as paired. Also there support to be a jumper between the 2 DC ports going from positive to positive and negative to negative. Putting the inverter on the DC port into paired, supposed to handle more current or something. Can't remember. Got to read that manual again.

CapLeaker, The "PAR' switch according to my understanding of the manual is used to parallel more inverters together.

[mitsu2k]

what is the history of this thing ? like did it work then suddenly this fault ? any other factors that may have happened just prior to this particular fault ?

Pete, the history of this unit is as follows. The inverter was probably installed around 2014 based on the date code. About 3 years ago it got the E031 error which is where the relay contacts on the PCB arc and burn out. At that time I repaired it by reflowing the solder joints on the relay in question. about a year later same thing happened but on a different relay. I repaired it same way. Several months later, it happened a third time and again on a different relay. This time I decided to reinforce the traces using some copper wire to allow more current to flow so the contacts would not arc and burn out. This seemed to work very well however I neglected to add the copper wire on one of the relay contacts. a couple months after that, I noticed that the inverter was not working and the red GFI light was on. So again I opened it up and found that the one relay contact that I did not reinforce with wire had burned out. However, this time that relay was melted pretty good and was not functional. I replaced all 4 relays at that time and reinforced all the pads/contacts with wire. Reinstalled it and the GFI light did not go away. So here we are today.

I would like to add that the very last time I mentioned above, there were no error messages on the display. The 3 previous times I had the E031 error on the display and the alarm led was lit but no GFI light.

[petehall347]

so it looks like gfi coincides with the 4th relay then . what is that relay for ?
maybe set your meter on megohms and check between the ground and around that 4th relay looking for leakage on the board . it does look as if the inverter is seeing leakage from somewhere .

[mitsu2k]

so it looks like gfi coincides with the 4th relay then . what is that relay for ?
maybe set your meter on megohms and check between the ground and around that 4th relay looking for leakage on the board . it does look as if the inverter is seeing leakage from somewhere .

the 4 relays are on the AC side. During normal operation, you can hear the relays cycling on/off.

[mitsu2k]

I have a question about those 4 MOVs. When I measure voltage between positive and earth ground, I get about 145V. When I remove the MOVs and measure without them, the voltage increases to around 194V. So the MOVs are suppressing some voltage. I am wondering if these MOVs are getting weak and they should be suppressing more. I did find that the middle leg of the MOVs of the positive input is connected directly to earth ground. On the negative the middle leg is connected directly to the GRP terminals that goes to that second board. I have went ahead and ordered some new MOVs and I should have them tomorrow. So I guess time will tell if this is the problem. The thing that strikes me odd is the blue MOVs on the AC side both test greater than 4000 MegaOhms with my megger. But these red ones are far below that. I know this is not a proper test but the specs of these MOVs are similar, at least close enough so I would think the results shouldn't be that far off. Just my crazy brain thinking without the proper expertise and experience. What if these MOVs are actually there for GFCI purposes rather than surge? Any thoughts?

[ssrkh]

listen you guys most of the times Ground fault comes with the CT what u need to do is just bypass CT by jumpering ground to Output of the CT so u will know where the fault is comming from and after that if u have again same fault of not performing initialization completely then watchdog is getting the bit High from the EC embedded controller so replace the controller fault will gone thanks me later bye