My Solaredge system dead. How to figure if it's an optimizer or inverter that's bad?

[kny]

Actual strings are 13 and 9. Logical layout is wrong. I don't care about that, not an issue.

Today, AC volts rose from 244.85 to 252.12 (7.3) across 5 minute data points. This is at 8am when the system then shut down until evening. Note system is already "broken" at this point.

Attached is the AC Volt, DC Volt, AC Power for Friday, showing behavior when whatever happened to "break" the system. You will see my SE6000 was producing 6.68kw at 1:17pm, well above its 6kw max. That 6.68kw is the greatest output I can find anywhere in the 18 month history. It also seems to have broken my inverter. DC Volts has always been around 370 up until that moment in time. That 6.68kw wreaked havoc, shot DC Volts up to 440 and DC Volts now are always up in the 400s anytime more than the system is putting out more than about 1kw.

Maybe I have bad AC connections. Maybe I have undersized wiring. Maybe my optimizers aren't grounded properly. But, that has all been like this for 18 months and the system has performed properly. But, once we had a 55 degree bright sun May 25th putting out 6.68kw from my 7.2kw array, and something went haywire from that point forward. Bad AC connection cannot explain that.

[kny]

Man, this is crazy. I get that little 7-8 volt hiccup every morning. I don't think it's at all related to the solar. I wonder if it could even be external to my house. I think that 8 volt rise is a red herring. Weird stuff.

[ButchDeal]

We have had cooler clear days in the past 18 months than may 25th. The system has multiple issues, no grounding on optimizers, undersized ac wires, likely poor ac connections.
Likely the optimizers got some ground for a while till the rails corroded enough to prevent good grounding.

The inverter tried to compensate and the optimizers tried to compensate but with out proper grounding and small wire forcing higher voltages, things fell apparent quickly. It is clear that the inverter and optimizers were trying to compensate with the higher DC voltages.

This should fall under inverter warranty but you also have underlying install problems that need to be addressed as well or the replacement inverter is going to be in the same shape soon. I would send a note to support@solaredge.com and have them investigate. Give them the date and issue and as much information as you have. Your installer should also have an install warranty that covers whatever solaredge doesn't cover.

[ButchDeal]

Man, this is crazy. I get that little 7-8 volt hiccup every morning. I don't think it's at all related to the solar. I wonder if it could even be external to my house. I think that 8 volt rise is a red herring. Weird stuff.

No it is not. Your inverter is trying to push amps down a wire that is too small with poor connections. It is related. I don;t see that kind of voltage rise on any system we monitor even ones with 150 yard connections but they are on properly sized cables. You can see even in the best case you would have a 5 volt rise when pushing 25 amps with this inverter on that gauge wire.

http://www.calculator.net/voltage-drop-calculator.html?material=copper&wiresize=3.277&voltage=240&phase=ac&noofconductor=1&distance=100&distanceunit=feet&amperes=25&x=81&y=18

[kny]

My inverter is bad. Back in April on consecutive days I noticed that the inverter was putting out zero at times. Then it went away and I thought nothing more of it. Now that I pull up the chart data on those two days and it looks like the attached. The inverter was on the fritz way back in April 11/12. No voltage rises. No extraordinary draws. Nothing to explain that behavior. And now it's toast. And now I'm also pissed at my installers. Definitely will get solaredge involved.

[solarix]

I keep harping on inverter reliability.... Here the event that steered me away from SolarEdge. Blown Capacitors.pdf

[solardreamer]

I keep harping on inverter reliability.... Here the event that steered me away from SolarEdge. [ATTACH]n351290[/ATTACH]

Is this picture for a recent SolarEdge inverter? The OP's story makes more convinced in my decision to choose microinverters as a key reason was avoid total shutdown.

Regarding excessive inverter output causing AC voltage to become too high, shouldn't the inverter first shutdown some optimizers to try to reduce total power generation before shutting down the whole inverter? When I was shopping for solar, I was told SolarEdge with optimizers would behave pretty much like microinverters.

[bcroe]

Is this picture for a recent SolarEdge inverter? The OP's story makes more convinced in my decision to choose microinverters as a key reason was avoid total shutdown.

Regarding excessive inverter output causing AC voltage to become too high, shouldn't the inverter first shutdown some optimizers to try to reduce total power generation before shutting down the whole inverter? When I was shopping for solar, I was told SolarEdge with optimizers would behave pretty much like microinverters.

I suppose, the number of micro inverters remaining on line could be viewed as a way to handle excessive AC
line voltage.

I don't think any private level grid tie inverter has provision to lower output to limit AC line voltage. Since every
installation has a different impedance and voltage situation, a one-fits-all solution might be difficult. Maybe the
mfrs could be convinced to come up with a gradual power reduction vs AC voltage, but that could cost a lot of
production if trip out isn't likely. Remember, this isn't even supposed to happen. Bruce Roe

[tyab]

(this may have been already answered, have not read every post after my vacation)

From the specs, the SE6000A-US has a max output of 25amps. That means with the 1.25% safety factor and rounding up the the next trade size you need a 40amp OCPD, which #10 wire cannot be used unless every terminal and conduit is 90C rated. At max output of 25 amps the 100' of #10 is about 2.6% voltage loss at that 90C temperature. One would have to do the adjustments for temperature to see if you could still get away with #10 at the 90C rating. My guess is the #10 wire is contributing to the overvoltage conditions - reducing the margin of tolerance the inverter has to work with. This is also assuming that your inverter is directly connected to the service panel (ie, not to a feeder on another sub-panel) so there are no significant additional losses.

[ButchDeal]

Is this picture for a recent SolarEdge inverter? The OP's story makes more convinced in my decision to choose microinverters as a key reason was avoid total shutdown.

Regarding excessive inverter output causing AC voltage to become too high, shouldn't the inverter first shutdown some optimizers to try to reduce total power generation before shutting down the whole inverter? When I was shopping for solar, I was told SolarEdge with optimizers would behave pretty much like microinverters.

This is an improperly installed system. I am fairly certain that a similarly installed micro setup would have failed earlier, if not imediatly. Try removing your grounding on all the micros then connect them with a 100 foot AC wire that is two sizes too small forcing nearly 3% voltage rise and see what happens.

[kny]

(this may have been already answered, have not read every post after my vacation)

From the specs, the SE6000A-US has a max output of 25amps. That means with the 1.25% safety factor and rounding up the the next trade size you need a 40amp OCPD, which #10 wire cannot be used unless every terminal and conduit is 90C rated. At max output of 25 amps the 100' of #10 is about 2.6% voltage loss at that 90C temperature. One would have to do the adjustments for temperature to see if you could still get away with #10 at the 90C rating. My guess is the #10 wire is contributing to the overvoltage conditions - reducing the margin of tolerance the inverter has to work with. This is also assuming that your inverter is directly connected to the service panel (ie, not to a feeder on another sub-panel) so there are no significant additional losses.

Thanks. Wire length is closer to 50 feet than the 100 feet I stated previously. ~2 foot run from inverter to AC disconnect and then about 50' run to back-fed breaker at main panel. More direct route than I thought.

I have identified the power optimizer that the inverter reports as "Non-reporting". This optimizer, however, does show in the monitoring portal with data and recent "last measurement" timestamp. So, it is alive and at least reporting data via ip, but the inverter does not see it.

[ButchDeal]

Thanks. Wire length is closer to 50 feet than the 100 feet I stated previously. ~2 foot run from inverter to AC disconnect and then about 50' run to back-fed breaker at main panel. More direct route than I thought.

I have identified the power optimizer that the inverter reports as "Non-reporting". This optimizer, however, does show in the monitoring portal with data and recent "last measurement" timestamp. So, it is alive and at least reporting data via ip, but the inverter does not see it.

it is still too small of a wire.

The optimizers do not report via IP. they send their data to the inverter and the inverter sends the data to the cloud.

[sensij]

I think Butch mentioned it in an earlier post, but re-pairing the optimizers should be an early step in the troubleshooting when not all are reporting.

I'm using 8 awg for a 40 ft run on a 7600 W inverter, almost went with 6 awg. 10 is too small.

[sensij]

... which #10 wire cannot be used unless every terminal and conduit is 90C rated.

90 deg terminals don't exist in this application. 60 or 75 deg for any consumer or commercial equipment. 10 awg is not code compliant for this inverter. Hopefully the installer at least used only a 30 breaker with it, at least then the conductor is protected, and the violation shifts toward having an undersized breaker for the supply.

[sensij]

I suppose, the number of micro inverters remaining on line could be viewed as a way to handle excessive AC
line voltage.

I don't think any private level grid tie inverter has provision to lower output to limit AC line voltage. Since every
installation has a different impedance and voltage situation, a one-fits-all solution might be difficult. Maybe the
mfrs could be convinced to come up with a gradual power reduction vs AC voltage, but that could cost a lot of
production if trip out isn't likely. Remember, this isn't even supposed to happen. Bruce Roe

There is no reason to take individual panels off line in an mppt system. The mppt is capable of moving off of the maximum power point to limit power output. This functionality already exists as "clipping", and can be set to any arbitrary power output maximum withing the inverters rating. When a Solaredge system is provided data from a revenue grade meter, it can do more advanced power management like zero backfeed into the grid, if desired.