Stuart:
Thank you for the follow up. Valuable information. A generator vendor just today proposed the use of an RDT unit to place between two generators and the input to an off-grid inverter/charger system. The idea is to have an automated means to start a secondary generator if the primary generator fails to start. I read the RDT manual and I don’t believe the RDT will do what I describe above. The RDT can only automatically transfer if the primary voltage source becomes de-energized. I did think of a way to make the RDT work for us because we will connect it to a Sunny Island system: We could connect Relay 1 to start generator 1 if the SOC goes below a certain value, let’s say 30%, hypothetically. We could then program Relay 2 in load shed mode (Lod1SocTm1Str) to close at a lower SOC, let’s say 20%. This way if the primary generator does not start at 30% SOC the secondary starts at 20%. Once the Secondary generator starts the RDT will transfer. Does this seem feasible? By the way, I recall there are upper and lower limits to the values one can enter into Lod1SocTm1Str and Lod1SocTm1Stp. Is my memory correct and does anyone know what those limits are? That information is not in the manual that I can find. Thanks in advance. 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-boun...@lists.re-wrenches.org] *On Behalf Of *Stuart Kriendler via RE-wrenches *Sent:* Friday, January 17, 2025 7:29 AM *To:* Mac Lewis *Cc:* Stuart Kriendler; RE-wrenches *Subject:* Re: [RE-wrenches] ATS models to bypass GT hybrid inverters for maintenance/faults Many thanks again Mac and Wrenches, This is now put to bed with confirmation the only listed 200A ATS that will work without a 12V switching controller that I could find around the $1k mark is indeed the Kohler RDT series. (All currently manufactured Generac, Briggs & Stratton and Cummins ATS options require a controller to talk to the same name brand gene to switch/transfer, or a Mcgiver move.) I found a supplier in Florida who gave a slight volume discount and seems solid. Here is a link to the product, pricing, specs and manual through them: https://bnhgenerators.com/product/kohler-200-amp-rdt-ats-rdt-cfnc-0200a-qs7/ And another supplier option with similar pricing, and the 100A version readily available in case helpful: https://www.electricgeneratorsdirect.com/Kohler-RDT-CFNC-0200A-QS7/p2202.html Best to all and thanks again. Sunniest regards, Stuart 441 599 2105 On Tue, 14 Jan 2025 at 21:02, Mac Lewis <maclew...@gmail.com> wrote: Hi Stuart, The Kohler RDT switch is a much better switch for what you are doing; it is a power seeking switch with no accessory device communication needed. It is more expensive than the RXT switch because it has its own brain board. A Kohler tech can adjust the delays for you if needed but the defaults are good. We have a few of them out there with no issues. They have them available as service entrance rated/indoor/outdoor etc. Good Luck! On Tue, Jan 14, 2025 at 2:55 PM August Goers via RE-wrenches < re-wrenches@lists.re-wrenches.org> wrote: Hi Stuart, Got it, now I see you're working with the MidNite AIO. This ATS topic came up not too long ago and I posted that we used to have success with Briggs & Stratton ATS units back when we were installing SMA Sunny Island systems. The Briggs unit does not need a control from an external source, it just switches over automatically (with a few second delay) once utility power is lost. We never had a single problem with these transfer switches. You might check them out: https://www.nationwidegenerators.com/briggs-stratton-071270-200-amp-se-rated-120-240v-1ph-ats/?srsltid=AfmBOorCds2ktOcsHUf3GWmX5ba70K-ynjOcm1iizzIW6X-9OkSVpfHA I know that Briggs went through a bankruptcy a few years ago, but maybe they're still alive and kicking now. August On Tue, Jan 14, 2025 at 1:29 PM Stuart Kriendler <stuartkriend...@gmail.com> wrote: Much appreciated August, Yes, that fancy Enphase System Controller is a nice piece of kit, overseen a few of those and it is nice they pass through the grid power if there is an issue, most of the time. ;-) I'm in love with the MN AIO, the build quality is impressive and great value for money, with the CBI breakers and features mentioned earlier etc. all built in. Now seen an engineering sample do the business in an rugged off-grid scenario for a few months and feel confident it will be a great GT hybrid option, one catch is the need for a 3rd party ATS though. (Hoping Midnite will make one of their own in time, as well as a wireway to marry the PowerFlo 16 and AIO, both such nicely built solid equipment). Hopefully the Kohler RXT or Generac can work to keep the ATS cost below $1k! Sunniest regards, Stuart 441 599 2105 On Tue, 14 Jan 2025 at 16:02, August Goers <aug...@luminalt.com> wrote: Hi Stuart - Many grid tied PV/ESS manufacturers (Enphase, SolarEdge, Franklin, Tesla to name a few) now have a Microgrid Interconnect Device (MID) that essentially acts as a smart transfer switch thus eliminating the need for a 3rd party automatic transfer switch. What brands equipment are you looking at? Best, August On Tue, Jan 14, 2025 at 11:10 AM Stuart Kriendler via RE-wrenches < re-wrenches@lists.re-wrenches.org> wrote: 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 _______________________________________________ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-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 _______________________________________________ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-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 -- Mac Lewis "Yo solo sé que no sé nada." *-Sócrates*
_______________________________________________ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-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
