[RE-wrenches] All-In-Ones / Sol-Ark fail

Tue Oct 15 11:56:40 PDT 2024

I am happy to report that these issues are resolved, and the system is
operating normally after replacing the broken MC4 and re-pulling wire for
the home run of the faulted string.

That second issue emanated from my guys pulling wire through a conduit
underground that evidently had some rocks in it, which damaged the
insulation on a wire. One thing led to another, and some bad choices led to
an issue that could have been worse. It was a good learning lesson.

I'm still fuming over how this causes non-affected inverters to shut down.
I will definitely look into how the Midnite AIO is different. I don't want
to write off the AIO concept over this one issue.

Jason Szumlanski
Principal Solar Designer | Florida Solar Design Group
NABCEP Certified Solar Professional (PVIP)
Florida State Certified Solar Contractor CVC56956
Florida Certified Electrical Contractor EC13013208

On Mon, Oct 14, 2024 at 11:18 PM Jason Szumlanski <
jason at floridasolardesigngroup.com> wrote:

> Diagnosis: No broken panels. Two different issues. We found a broken MC4
> connector, possibly due to flying debris. We also found a melted Polaris
> tap that got wet (long story, our fault).
>
> These two issues happened at seeming the exact same time during the
> hurricane, but were completely different events. The next morning it caused
> faults on two of four inverters when the sun came up, and the other two
> inverters faulted out as "parallel faults." That's a behavior that seems
> unacceptable. Neither of the initially faulted inverters were the master,
> either.
>
> One bad PV string on one out of four inverters should not cause a total
> system failure to operate.
>
> Jason
>
>
> On Fri, Oct 11, 2024, 3:59 PM Jason Szumlanski <
> jason at floridasolardesigngroup.com> wrote:
>
>> That is the exact error! But I don't think that explains how I have one
>> string over the expected voltage and one string under. It's definitely
>> worth checking, nonetheless. This array is 12 feet in the air and pitched
>> at 5 degrees, so you can't see the glass from the ground.
>>
>> It is conceivable that I have two issues. The voltage issue could be a
>> wiring issue and the inverters may have faulted out due to broken modules.
>> There were tropical force winds there at the time.
>>
>> Jason Szumlanski
>> Principal Solar Designer | Florida Solar Design Group
>> NABCEP Certified Solar Professional (PVIP)
>> Florida State Certified Solar Contractor CVC56956
>> Florida Certified Electrical Contractor EC13013208
>>
>>
>> On Fri, Oct 11, 2024 at 3:49 PM Maverick Brown <
>> maverick at mavericksolar.com> wrote:
>>
>>> Jason
>>>
>>> Which fault are you getting?
>>>
>>> This spring I was getting F23-Tz_GFCLO randomly on an upper roof array.
>>>
>>> After further investigation, I found several modules with broken glass.
>>> After replacing the mods, all is well.
>>>
>>> Thank you,
>>>
>>> Maverick
>>>
>>> Maverick Brown
>>> Off-Grid Solar Commander since 2006
>>> Maverick Solar Enterprises, Inc.
>>>  • Solar Commander Remote Power
>>>  • SunFlow Systems Cathodic Protection
>>> maverick at mavericksolar.com
>>> 512-460-9825
>>>
>>>
>>>
>>> On Oct 11, 2024, at 1:39 PM, Jason Szumlanski via RE-wrenches <
>>> re-wrenches at lists.re-wrenches.org> wrote:
>>>
>>> 
>>> By shutting off the PV disconnects on the two affected inverters we were
>>> able to make the system work successfully today. As I mentioned, we will
>>> dig into the actual faults on Monday. From the historical data, I found
>>> that this issue has actually been going on for a week before the faults
>>> started happening in the inverters. I'm not sure why the faults took so
>>> long to cause a shutdown of the inverters. Maybe it just "got worse" and
>>> finally triggered a fault. The first faults would have been  during the
>>> early band of rain from Hurricane Milton, so possibly water or wind put the
>>> issue over the top.
>>>
>>> Before the shutdown, each of the two affected inverters had one MPPT
>>> with voltages out of the expected range for the last week.
>>>
>>> All MPPT strings are 14 modules with 7 in series, 2 in parallel. Each
>>> string Voc is 342V and Vmp is 297V.
>>>
>>> On the first affected inverter, I was able to observe the bad string
>>> operating consistently around 370V to 400V+, which is obviously well above
>>> the Voc (and it's hot here in Florida). The good string on this inverter
>>> operated around 260-270V during the same time, which is the expected range.
>>>
>>> On the second affected inverter, I observed the bad string operating
>>> consistently around 100V to 130V+. The good string on this inverter
>>> operated around 260-270V during the same time, which again is the expected
>>> range.
>>>
>>> Graphs are attached for those of you who like that kind of stuff. These
>>> show a typical day after the issue started to occur, but before the
>>> inverter faults occurred.
>>>
>>> Incidentally, the average voltage of the two bad strings seems to be
>>> pretty close to the normal strings, so that is a good clue.
>>>
>>> Jason Szumlanski
>>> Principal Solar Designer | Florida Solar Design Group
>>> NABCEP Certified Solar Professional (PVIP)
>>> Florida State Certified Solar Contractor CVC56956
>>> Florida Certified Electrical Contractor EC13013208
>>>
>>>
>>> On Fri, Oct 11, 2024 at 6:55 AM Jason Szumlanski <
>>> jason at floridasolardesigngroup.com> wrote:
>>>
>>>> More interesting information... When the sun went down last night, the
>>>> fault cleared and the inverters started producing power again, drawing from
>>>> the batteries, and restarting the generator. The master inverter
>>>> "remembered" the generator was in it's charging cycle and hadn't reached
>>>> full battery yet.
>>>>
>>>> It's good that the inverters started inverting again. That's a plus. I
>>>> actually wish the generator hadn't started because it was unnecessary based
>>>> on battery voltage, which was near full anyway.
>>>>
>>>> Which brings me to another annoying behavior of the Sol-Arks that I
>>>> discovered in how the GEN Charge and GRID Charge parameters work with
>>>> signaling the two-wire start. If the battery voltage is 50V and the charge
>>>> parameter is set to 49V, the generator signal will not kick on of course –
>>>> the generator start relay is open. However, if you change the charge
>>>> parameter setpoint to, say 51V, the generator should start because the
>>>> battery voltage is below the setpoint. But that does not happen. The
>>>> battery voltage must "fall through" the parameter setting for the charging
>>>> to be triggered and the relay to close. If you are in a situation where you
>>>> need to get the generator on a charge cycle and then leave the site, the
>>>> only way I have found to do this is to set it to something very close to
>>>> the battery voltage, say 49.9V, put a heavy load on to drop the voltage
>>>> below the setpoint, let the generator start, then change the setpoint to
>>>> the desired 51V.
>>>>
>>>>
>>>> Back to the original issue – I dug into the string voltage data history
>>>> remotely and narrowed down the fault to two of the four inverters. I am
>>>> sending someone to shut down the PV DC switches on these two inverters
>>>> today in hopes that we can keep the power flowing during the day and
>>>> through the weekend. I'm planning on a Monday boat ride out there to see
>>>> what caused the fault(s). I will report back.
>>>>
>>>> Jason Szumlanski
>>>> Principal Solar Designer | Florida Solar Design Group
>>>> NABCEP Certified Solar Professional (PVIP)
>>>> Florida State Certified Solar Contractor CVC56956
>>>> Florida Certified Electrical Contractor EC13013208
>>>>
>>>>
>>>> On Thu, Oct 10, 2024 at 6:00 PM Lou Russo via RE-wrenches <
>>>> re-wrenches at lists.re-wrenches.org> wrote:
>>>>
>>>>> Aloha All,
>>>>>
>>>>> Thank you Jason. This is a huge and surprising issue. So much so that
>>>>> I dropped what I was doing and called Sol-Ark to confirm. Mind you this was
>>>>> level 1 support, but I was told this is what the Sol-Arks are supposed to
>>>>> do and it is a feature not a bug. Their take is if there is any fault on
>>>>> any one string, the Sol-Ark assumes the worst and shuts everything down.
>>>>>
>>>>> I wonder what solutions could be implemented on future installs to
>>>>> prevent this from happening?
>>>>>
>>>>> Aloha,
>>>>>
>>>>> Lou Russo
>>>>> Owner
>>>>> lou at spreesolarsystems.com
>>>>> Office - 808 345 6762
>>>>> Spree Solar Systems LLC
>>>>> CT-34322
>>>>>
>>>>>
>>>>>
>>>>> On Thu, Oct 10, 2024 at 11:45 AM Jason Szumlanski via RE-wrenches <
>>>>> re-wrenches at lists.re-wrenches.org> wrote:
>>>>>
>>>>>> I think it's more likely water in a J-box or possibly physical
>>>>>> damage, but someone passed by the property and did not observe any physical
>>>>>> damage to the array.
>>>>>>
>>>>>> Jason Szumlanski
>>>>>> Principal Solar Designer | Florida Solar Design Group
>>>>>> NABCEP Certified Solar Professional (PVIP)
>>>>>> Florida State Certified Solar Contractor CVC56956
>>>>>> Florida Certified Electrical Contractor EC13013208
>>>>>>
>>>>>>
>>>>>> On Thu, Oct 10, 2024 at 5:41 PM Jay <jay.peltz at gmail.com> wrote:
>>>>>>
>>>>>>> Jason
>>>>>>> What’s the possibllity it was a lighting strike?
>>>>>>>
>>>>>>> Jay
>>>>>>>
>>>>>>> On Oct 10, 2024, at 2:57 PM, Jason Szumlanski via RE-wrenches <
>>>>>>> re-wrenches at lists.re-wrenches.org> wrote:
>>>>>>>
>>>>>>> 
>>>>>>> We have been talking a lot recently about all-in-ones. I just had a
>>>>>>> massive fail during Hurricane Milton with a quad Sol-Ark 15K off-grid
>>>>>>> system that deserves some discussion about whether AIO is a good idea if it
>>>>>>> can't build in some resilience to errors. I'm not sure if the new Midnite
>>>>>>> unit is better in this respect, but this is what happened to the Sol-Ark
>>>>>>> system...
>>>>>>>
>>>>>>> Four inverters, each with 4 strings of PV paralleled to 2 MPPT per
>>>>>>> inverter. One of the slave units developed some sort of PV DC fault during
>>>>>>> the storm. This caused the slave inverter to shut down and throw an error,
>>>>>>> which in turn caused a parallel fault across all four inverters. Power
>>>>>>> output ceases at that point. Apparently the system keeps resetting because
>>>>>>> I have a cell modem that uploads data to Sol-Ark, but that cell modem is
>>>>>>> powered by the inverter outputs, so it must be getting power at least
>>>>>>> intermittently. The rest of the loads are basically flatlined according to
>>>>>>> the Sol-Ark data. It's mostly air conditioners, so they probably can't turn
>>>>>>> on fast enough before the PV fault causes another shutdown.
>>>>>>>
>>>>>>> So, in essence, one of 16 strings of PV develops a fault, and that
>>>>>>> causes all four inverters to malfunction? What is the point of redundancy
>>>>>>> if a fault of one results in a fault of all?! If there is a true PV input
>>>>>>> fault, shouldn't that just shut down that MPPT, or perhaps all of the PV DC
>>>>>>> input to that inverter? And why can't this inverter continue to invert
>>>>>>> power from the batteries and charge from a generator when there is a DC
>>>>>>> input fault that could be programmatically isolated and ignored?
>>>>>>>
>>>>>>> This is a bad design in my opinion, and something I hadn't
>>>>>>> considered. If the faulted inverter can't function with a DC input fault,
>>>>>>> it should just take itself out of the game. (This is 120/240 split phase,
>>>>>>> BTW). Is this how all AIO inverters work? One inverter fault on the DC side
>>>>>>> kills all paralleled units' AC output? Not good.
>>>>>>>
>>>>>>> This is a completely off-grid system on a remote island with no
>>>>>>> vehicle access, so it's not exactly easy to do a "truck roll" on this one,
>>>>>>> especially post-hurricane. To make matters worse, the generator was running
>>>>>>> at the time of the fault, as it was being signaled to run because the
>>>>>>> battery had reached the assigned charge voltage. The fault also killed the
>>>>>>> 2-wire start signal from the master, so the system also stopped passing
>>>>>>> through generator power to the loads. The house is dark.
>>>>>>>
>>>>>>>
>>>>>>> Jason Szumlanski
>>>>>>> Florida Solar Design Group
>>>>>>>
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>>>>> <Slave 2.jpg>
>>> <Slave 1.jpg>
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