I agree why wouldn’t you install the generator at the Gen input? Ok if you’ve got a ac couple then that eats up the Gen input.
But yeah brings up a lot of questions as to integration. Here is another. Does the sol ark know to reduce the charge rate if the generator is not as big as the grid which I would expect? Makes the case for multiple sets of CT’s to measure and allow for control. I’ll be curious what others think/know Jay > On Oct 19, 2026, at 4:10 PM, [email protected] wrote: > > > So I've always been of mindset that solar integrated downstream > (customer-side) of a whole-house generator was a backfeeding debacle to avoid > as a solar inverter had no means to backfeed into a generator as there is no > grid to export excess solar production too. > > So while researching a possible method I come across the SolArk schematic for > integration to whole house generator integration and even though my eyes have > gone across it dozens of times, this was first time I really LOOKED at it. > Was shocked to see the whole house generator upstream of the inverter. > > Seems to me that one only wants an inverter with a whole-house generator if > you want the solar and the battery's energy management features. The always > excellent SolArk tech said in this config the inverter knows the gen is on > via the 2-wire start wires; this was eye opening to me as I had a paradigm > this was only a relay to trigger the gen on and I never considered the > two-way communication part. The CT's at the transfer switch would measure gen > output and I suppose the inverter will "know" that output via the associate > CT wires. > > So my questions are: > > Why would we ever want the inverter to produce during a grid outage when the > gen is running? > If the gen power was "clean enough" that the inverter kept on making power, > is the SolArk truly "know" via the 2-wire start that the gen is on and to not > make (any?) power? > Would the SolArk try to make power to offset the power of the Gen and reduce > that to zero or does that functionality go away because the SolArk knows the > gen is on? > > And the final question: If the SolArk is in this configuration only to > provide energy management (since the whole-house gen is providing whole house > backup) can I put this schematic in place on a house where there is a 400A > service and two 200A panels but since I'm wanting to retain the whole house > gen backup but also want the ESS energy management, one SolArk 18 provides > that in this config on just one of the panels: I have the whole house backup > but using battery power from one inverter to meet energy management needs. > > Been doing this for almost 14 years and for some reason, this schematic > nearly fried my brain to mush... > > Any thoughts or inside or knowledge you can share? > > PPS - one more question - this helps me AC couple a Fronius 12.5 onto the GEN > inputs, too and 'solves' the quandary I was having. > > <image.png> > > Howard "Scot" Arey > Owner, Solar CenTex > > NABCEP PV Installation Professional > TECL 29755 > 254-300-1228 > <image.png> > > _______________________________________________ > List sponsored by Redwood Alliance > > Pay optional member dues here: http://re-wrenches.org > > List Address: [email protected] > > Change listserver email address & settings: > https://lists.re-wrenches.org/mailman/options/re-wrenches_lists.re-wrenches.org/ > > There are two list archives for searching. When one doesn't work, try the > other: > https://www.mail-archive.com/[email protected]/ > https://lists.re-wrenches.org/pipermail/re-wrenches_lists.re-wrenches.org/ > > List rules & etiquette: > http://www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > http://www.members.re-wrenches.org
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