Hi Nick,

Yes I have done this.  Not often but I did a site with a whole home
generator with an SMA inverter using the 50A version.  This homeowner is a
techie and would let me know immediately if it had failed (with
spreadsheets and second by second data!).  In this case, it was a Generac
generator brand as well.  I'd look closely at the relay ratings.  Perhaps
the downstream load exceeded the relay ratings in some way (inrush etc).
You could consider using one as a pilot relay for an appropriate relay
rating if that was overlooked originally.

Also, was it a logic board failure or a contactor failure?

I don't see a reason why this wouldn't work fine but I'm not surprised that
Generac tech support was confused.  For an inverter output, it should be
programmed for full lockout.  This should be a fairly simple operation
since the inverter shouldn't try to reconnect for a few minutes after a
power outage, no current should be flowing during the lockout.

Another company is doing a similar product that I've looked into as well,
but I've never used:

https://www.pspproducts.com/load-management/sak-60-wireless-load-management/

This looks pretty good and not generator brand specific (although I may
want to see what products they have tested with it).

It's kind of too easy not to try...

On Thu, Jun 20, 2024 at 11:45 PM Nick Lucchese via RE-wrenches <
re-wrenches@lists.re-wrenches.org> wrote:

> Greetings Mac,
> Have you personally had success with this by chance? I inherited
> maintenance of a system for a friend whose original installer went out of
> business and this was their original approach as well however they and they
> had used the 100 amp version (even though the system produces just 24
> amps). When I originally inspected 3 years ago the system was fine but the
> SMM failed last fall and the homeowner missed out on a few months of
> production before noticing. Since this was the first time I had come across
> this combo I reached out to Generac for approval and two
> different technical support departments seemed puzzled it was used for this
> purpose and advised against it. I'm now seeking a similar solution like
> William but replacing the SMM with a new one sure would make my life
> easier. Couldn't really tell if I was speaking to new employees at Generac
> and they just weren't willing to look into it deeper or if it's truly a bad
> equipment pairing. Looks like it worked for about 5 years before failing
> and I was able to determine the failure occurred the last time the
> generator had ran during a grid outage. Another local electrician had said
> there had been a bad run of the SMM's which adds additional justification
> to perhaps try it out again. If you've used the SMM's for this purpose have
> you used the 50 as well as the 100 amp version?
>
> Thanks for the input, Nick
>
> On Thu, Jun 20, 2024 at 4:28 AM Mac Lewis via RE-wrenches <
> re-wrenches@lists.re-wrenches.org> wrote:
>
>> Hi William,
>>
>> I don't want to hijack this thread but I want to give you another idea
>> for disconnecting the Enphase circuit.
>>
>> Generac makes a very convenient load shed device called Smart Management
>> Module SMM50.  This may be a good option for you.  Instead of having a
>> signal wire/trench etc, it is a pass through relay with a board that
>> samples the line voltage.  If it senses that the voltage is supplied by a
>> generator, you can program it to lock out the load.  You could place it on
>> the interconnection of the enphase circuit.  They only guarantee it will
>> work with a Generac generator, but I suspect it will work with other brands
>> as well.  This could be worth considering.
>>
>> Good luck!
>>
>>
>>
>> On Thu, Jun 20, 2024 at 12:35 AM William Miller via RE-wrenches <
>> re-wrenches@lists.re-wrenches.org> wrote:
>>
>>> Friends:
>>>
>>>
>>>
>>> I have an installation of 12 Enphase IQ inverters that is downstream
>>> from a generator transfer switch.  During power outages the generator will
>>> run poorly when the Enphase is on and the sun is shining.  The problems go
>>> away when the Enphase is shut off.  No surprises about this.
>>>
>>>
>>>
>>> The Enphase is installed on a barn about 150 conduit feet from the
>>> generator transfer switch.  My plan is to create a low voltage signal when
>>> the generator is running and send it to a coil on a contactor in the barn.
>>> Said contactor will disconnect the 12 micro-inverters.
>>>
>>>
>>>
>>> There is existing one 26 AWG pairs of a Cat 6 cable running between the
>>> buildings.  I have found a two pole, 30A contactor that draws 7 watts on
>>> the coil.  The voltage drop calcs on 150 feet of 26 AWG wire shows a 24
>>> volt signal will not cause excessive voltage drop (~4%).
>>>
>>>
>>>
>>> Here is where I am uncertain:  Should I run 24 volts AC or DC?  My
>>> concern about DC is if there are any damp connections, electrolysis will
>>> occur that might erode the 26 AWG conductors.  We’ve all seen powder where
>>> copper used to be.  Is AC less susceptible to electrolysis?  My research
>>> has turned up no pertinent conclusions.
>>>
>>>
>>>
>>> Thanks in advance.
>>>
>>>
>>>
>>> William Miller
>>>
>>>
>>>
>>> Miller Solar
>>>
>>> 17395 Oak Road, Atascadero, CA 93422
>>>
>>> 805-438-5600
>>>
>>> www.millersolar.com
>>>
>>> CA Lic. 773985
>>>
>>>
>>>
>>>
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>>
>> --
>>
>>
>>
>> Mac Lewis
>>
>> *"Yo solo sé que no sé nada." -Sócrates*
>> _______________________________________________
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-- 



Mac Lewis

*"Yo solo sé que no sé nada." -Sócrates*
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