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

Fri Oct 11 15:11:59 PDT 2024

I don't think that's how LBCO works exactly with AIOs. If the Sol-Ark
reaches the "Shutdown" voltage parameter, it stops inverting, but when PV
is available again it does charge the battery and will start inverting
again when the "Restart" voltage is reached. The Shutdown parameter doesn't
actually "shut down" the inverter. It just stops inverting. I will continue
to send performance data via the comms dongle during this time as well.

Of course, the draw from the inverter itself can cause the battery to
continue to get depleted and a LiPO battery could eventually reach a point
where it's BMS shuts down. This is more problematic with small battery
banks relative to the idle consumption of the inverter. For large battery
banks this is a non-issue as long as the voltage parameters are set
conservatively.

But for sure the old school systems are hard to beat for reliability, or
maybe better put, resiliency and redundancy. Unfortunately they require
more hands on maintenance and "tinkering" than newer options, and there are
more components to fail. They are also harder to design and install. With
time being so valuable, it's getting impossible to support older systems in
a profitable way.

We need to challenge the AIO makers to understand the resilience and
redundancy that off-grid systems need. The flexibility to use them on or
off-grid is great, but we need them to be great at both, not just good if
they want to play in both markets.

I reject the "listing requirements made us do it" argument. There must be a
workaround to ensure that a ground fault on a single PV string connected to
one inverter would cause an AC output failure on all paralleled inverters.
That doesn't pass the logic test because you could simply turn off that
inverter without physically changing any wiring to resume power production.
In fact, I proved that today by simply turning off the DC input switch.
That should happen automatically!

Jason Szumlanski
Florida Solar Design Group

On Fri, Oct 11, 2024, 5:26 PM Ray Walters via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:

> Another reason to do separate charge controllers is Low battery. If the
> AIO inverter hits its LBCO, then it takes out the PV input as well. Then
> the draw of the BCM takes what's left in the battery, and you're into a
> dark start.  Generator won't even help.  AIOs are easy to install, but not
> as full proof as DC coupled PV systems.  Also, the inter communication is a
> major issue.  I've seen inter connected charge controllers take each other
> out, which really defeats the redundancy of having multiple units.  I'm
> sure many on the list will question my wisdom; but I usually don't
> interconnect any of the equipment from a comms stand point.  I use open
> loop charging based on voltage.
>
> I once had a pinched temp sensor, that thought the batteries were at 5000
> deg Kelvin.  It shut all 4 inverters down.  My most reliable multiple
> inverter setup is a four SW4048 system that is now 24 years old.  Each
> inverter feeds one leg of two load centers.  No comms, No 240 vac loads.
> No shut downs.  That is the gold standard, and none of the AIO stuff, nor
> the module level rapid shutdown etc, can even get close to the level of
> reliability we had in the past.  In the off grid world, shut downs can be
> life threatening, and all the additional "safety" stuff added to the code
> since, has actually made my off grid customers less safe.
>
> You have to think what happens if the battery gets low, and no one is
> home?  Can it recover on its own, like a traditional DC coupled Lead acid
> system?  Basically, If the system can't hit LBCO, recharge the next day,
> and automatically turn loads back on, we've gone backwards in our designs,
> and equipment selection. AIOs are inferior if they can't achieve this basic
> functionality.  If UL standards are causing this, then those standards are
> incorrect for critical off grid and backup applications.
>
> Ray Walters
> Remote Solar
> On 10/10/2024 4:02 PM, Eric Smiley via RE-wrenches wrote:
>
> Install stand-alone charge controllers. That is the only way to get
> redundancy.
>
> Eric Smiley (he/him) - Design Manager
>
>  250.703.6004
>  eric at vecoop.ca
>  888.386.0116
>  3-4997 Polkey Rd, Duncan BC, V9L 6W3
> <https://www.google.com/maps/search/4997+Polkey+Rd,%0D%0A++++++++++++++++++++++++++Duncan+BC,+V9L+6W3?entry=gmail&source=g>
>  viridiansolar.ca
> <https://www.google.com/url?q=https://viridiansolar.ca&source=gmail-html&ust=1702155901939000&usg=AOvVaw3SHpXB-WRSlzWmjpz4htqG>
>
>
>
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> services, recognising that these lands are unceded Indigenous territory. We
> are steadfast in our commitment to reconciliation and acknowledge the rich
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>
>
>
> On Thu, 10 Oct 2024 at 14:59, 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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