[RE-wrenches] GT w/ BB

[Jason Szumlanski]

I like the Sol-Ark idea having had a few dual-unit successes recently. In
terms of combining them, the Sol-ark manual has a good triple unit wiring
diagram on page 53. You would have to use two 400A panelboards with three
200A breakers for each to follow this diagram. However, I don't see the
point of a combining load center on the load side of the paralleled units.
The Sol-Arks each have a 200A integrated load breaker, so why not just
combine the outputs in a multi-tap connector or busbar? I think there is a
code-compliant way to make that work, but I haven't studied it with three
units.

I would definitely ditch the SolarEdge inverters and just make it DC
coupled to the Sol-Arks. You don't need these to be a failure point in the
system, and the AC coupling will reduce the energy production in backup
scenarios.

It sounds like you would have to get the six 200 feeders out of the
meter/main and into a new panelboard on the load side of the Sol-Arks. So
that's another required load center.

And if money is truly no object, I would consider a manual transfer switch
to bypass the inverters for service. I'm afraid to look up what a 400A DPDT
switch costs.


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


On Mon, Sep 18, 2023 at 1:14 PM Michael Morningstar via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:

> I've been asked to build a back up system for a grid connected estate. We
> haven't done many of these and I thought it best to ask those who have some
> questions before I go about reinventing the wheel.
>
> Here's the existing infrastructure.
> 1) 400amp Metered Main Distribution Panel with six 200amp feeders to
> various sub-panels on the property
> 2) 400amp ATS and 100kw Kohler rapid response generator
> 3) 20kw ground mount array with (2) SE Inverters located at the array.
> Feeder from array is 1,000 ft to Service. Six years old and wiring is janky.
> 4) Data logging for the last year shows peak demands of almost 40kw. This
> could increase as several of formerly vacant  guest residences could be
> occupied.
>
> My go to is almost always Schneider, however in this instance when I
> looked into a quad stack, or more It seems like some type of controller is
> needed to prevent imbalanced current passing through the relays during
> transfer. That left me a bit concerned. Has anyone successfully stacked 4
> or more XWPROs?
>
> Then there is the matter of AC or DC coupling? I really want no part in
> having anything to do with SE. The inverters are already looking pretty
> weathered taking the brunt of the prevailing winds and storms (they are
> mounted to one of the ground mount poles). Seems like a great waste to pull
> out the 4/0 feeders and replace strings. My other hesitancy with AC
> coupling is that we would lose PV monitoring and control.
>
> I've also considered Sol Ark 15's, like three of them. We've got some SA
> systems under are belt now and the only thing I can say that I like is the
> speed of installation and the 200amp pass through. Other than that, they
> leave me uninspired. One very large system continues to have glitches that
> SA just shrugs their shoulders about. If we were to do three 15's, *what's
> the preferred combining method?* All that I can come up with is a custom
> 400a panelboard w/ three 200a breakers.
>
> Price is not a consideration for this project. The new owners of this
> property (which is plagued with outages) have tasked me with building
> something that is ultra reliable and good take over in a situation where
> the grid is no longer available.
>
> Any suggestions or tips are appreciated.
>
> Michael
>
> --
>
> Michael Morningstar
>
>
> Morningstar Electric
>
> PO Box 1494
>
> Mount Shasta, CA 96067
>
> 530-921-0560
>
> mjmorningstar at gmail.com
>
>
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