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

Fri Oct 11 03:55:57 PDT 2024

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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