[RE-wrenches] ATS models to bypass GT hybrid inverters for maintenance/faults

[david quattro]

I’ve been doing this for a few years now, but not on every install. They’re
pretty expensive, more labor, one more component to fail, and takes up
significant wall space/aesthetic factor.
    GENERAC transfer switch requires you to rig a separate 12v power
supply, (normally this 12vdc comes from the generator start battery)  to
triggers transfer you have to trick the control module by shorting
“23Transfer” to Ground. Here is an excellent YouTube video demonstration.
https://youtu.be/rT_3JYZS9Mg?si=7EarqHXTddLSpKXe
    KOHLER:  use their RDT model !  Don’t use the RXT model, as their RXT
really does need a complex computer handshake signal from a true Kohler
generator.  The  _RDT_  is sweet - senses primary versus secondary, and
switches back and forth automatically.
David Q



On Tue, Jan 14, 2025 at 11:36 AM William Miller via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:

> Stuart:
>
>
>
> I understand the concern and appreciate the consideration to provide more
> reliability.  The approach you suggested sounds like a band-aid, not a
> cure.
>
>
>
> I do not know if this complete shutdown is required by the listing (a
> feature) or is just a bug.  Does anyone have information on this?  If it is
> not required, the manufacturers should certainly correct these problems.
>
>
>
> This may be a case against All-in-on inverters.  If there is a PV arc
> fault on systems with separate charge controllers the inverter will not
> curtail operation and it’s pass-through capabilities.
>
>
>
> William Miller
>
>
>
> Miller Solar
>
> 17395 Oak Road, Atascadero, CA 93422
>
> 805-438-5600
>
> www.millersolar.com
>
> CA Lic. 773985
>
>
>
>
>
> *From:* RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] *On
> Behalf Of *Stuart Kriendler via RE-wrenches
> *Sent:* Tuesday, January 14, 2025 11:09 AM
> *To:* re-wrenches at lists.re-wrenches.org
> *Cc:* Stuart Kriendler
> *Subject:* [RE-wrenches] ATS models to bypass GT hybrid inverters for
> maintenance/faults
>
>
>
> Good day Wrenches,
>
>
>
> 2025 looks to be the year for installing more grid tied (GT) battery back
> up hybrid inverters on new and existing GT PV systems in a whole house
> backup scenario
>
> i.e. Utility - Hybrid Inverter - House Loads
>
>
>
> With these newer GT hybrids so 'sensitive', any fault on the PV side can
> cause them to shut down, thus stopping power to the house.
>
> To minimise this it seems sensible to add an ATS to the system such that
> if/when the hybrid faults, the ATS w switch to grid power, bypass the
> hybrid, and power the house.
>
> This could save an emergency truck roll or late night phone call for
> installers.
>
>
>
> Anyone have experience on good value-for-money Listed automatic transfer
> switches that would do the job, 200A, 120/240V?
>
>
>
> Two name brand options that came up on the less expensive end of the
> spectrum are:
>
> - Generac RXSW200A3 (
> https://www.generac.com/residential-products/standby-generator-transfer-switches/automatic/rxsw200a3/
> )
>
>
>
> - *Kohler 200-amp, Service Entrance RXT ATS | RXT-JFNC-200ASEQS4 (*
> https://www.kohler.com/content/dam/kohler-com-NA/Lifestyle/PDF/PDF-g11152.pdf
> )
>
>
>
> However, they each say their ATSs must be used with the corresponding
> generator.
>
>
>
> I would imagine a simple 'grid sense' functionality would mean that if the
> hybrid's output was connected to the Grid/Normal lugs and the grid was
> connected to the Gene/Backup lugs in the ATS it should work.
>
> However I don't want to end up with an expensive surprise in a relatively
> remote location where I operate!
>
>
>
> Would appreciate any feedback with experience with the above or other ATS
> models or how people are future proofing for this scenario?
> To do future maintenance/torque checks etc. in a GT hybrid whole home
> backup situation, it would be nice to bypass the inverter and keep the
> house powered for safety and homeowner convenience in general.
>
>
>
> Thanks and best.
>
>
>
> Sunniest regards,
>
> Stuart
>
> 441 599 2105
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