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

[Jason Szumlanski]

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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