I definitely understand that I can't prevent it 100%, but I can surely mitigate the likelihood. It's highly unlikely that all 10 refrigerators will all start simultaneously based on temperature with the well pump and two air conditioners except when power is first applied. Moreso than the ATS changeover, I'm concerned about scenarios where everything is completely off at the property and the inverter breakers are flipped on. Then I'm essentially guaranteed I'll have 15 motors all trying to start at the same time. I'm planning 27-32kW of capacity, which may well be enough depending on how gentle the HVAC units start, but I want to have a strategy in case things don't go as planned.
I was thinking that the ATS would be a good strategy to trigger time delays because it would be implemented whether it was a startup from no power source or during power source transfer. The challenge here is that more than half of these loads will be used maybe a few weeks a year. I'm tasked with designing a system that will operate efficiently with both high and low occupancy levels, and it's only responsible of me to investigate ways to reduce the budget requirement for the total system. Money is probably not a factor here, but bigger, bigger, bigger also means bigger headaches when you have 8 inverters to maintain rather than 6 or 4. I do have some other thoughts like ensuring the well pump doesn't turn on while the Air Conditioning is running. Since it's on a float switch with ample at-grade storage, I don't really care if it runs only at periods of light load. You do have a point about turning refrigerators on and off by switching power. I might look into ways to cut the compressor using controls in the refrigerators instead. That will be a conversation with Sub-Z to see if they care that power is cycled during operation. On Wed, Sep 11, 2019 at 8:16 PM Jay <[email protected]> wrote: > You’ve got to plan on them all starting at once anyway. You can’t expect > that it’ll never happen. > > And really how do you prevent it. The refrigerators and AC’s are on all > the time waiting for the thermostat to activate. And it’s not good to turn > a working fridge on/off especially is the compressor is running. > > Bigger loads, bigger inverters, bigger dollars. > > Jay > > > > On Sep 11, 2019, at 4:24 PM, Jason Szumlanski < > [email protected]> wrote: > > That is what I was thinking, but how will the contactor coils "know" when > the ATS switches to inverter power. I'm thinking I need to use an AUX relay > or a series of relays to produce the desired result. I don't think it will > be necessary when going from solar to generator in this case, but maybe. I > guess the question is how to activate the time delay any time the ATS > switches over. That would be the easiest solution maybe. > > I'm probably looking at a quad Conext XW+ system here. Even at over 100A @ > 240V continuous rating I'm anticipating some startup issues with all those > motors (I forgot to mention well and pressure pumps also!) > > Jason > > > > On Wed, Sep 11, 2019 at 5:50 PM Michael Morningstar < > [email protected]> wrote: > >> Put the loads on contractors, control the contractors with adjustable >> time delay relays. Stagger the timing. >> >> On Sep 11, 2019, at 2:41 PM, Jason Szumlanski < >> [email protected]> wrote: >> >> In an off-grid situation I'm looking for a strategy to manage transfer >> from generator power to inverter power because I have a lot of high startup >> load appliances planned for a system. Think 8 mini-refrigerators, one sub-z >> large refrigerator, and an under-cabinet ice maker, not to mention air >> conditioning. I would like to start these loads in stages if they all call >> to start up immediately upon system startup or during ATS switch over. Any >> ideas? >> >> I guess while I'm on the subject I should ask about my eye-roll, >> keep-me-up-a-night, giving-me-heartburn problem with this ice maker. It's >> going to be outdoors in Florida and they expect it to make 25-50 pounds of >> ice per day. I am finding it really hard to estimate energy use for this >> appliance. Any ideas (other than the obvious "don't do it" answer)? >> >> >> Jason Szumlanski >> Florida Solar Design Group >> >> _______________________________________________ >> List sponsored by Redwood Alliance >> >> List Address: [email protected] >> >> Change listserver email address & settings: >> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> >> List-Archive: >> http://www.mail-archive.com/[email protected]/maillist.html >> >> List rules & etiquette: >> www.re-wrenches.org/etiquette.htm >> >> Check out or update participant bios: >> www.members.re-wrenches.org >> >> _______________________________________________ >> List sponsored by Redwood Alliance >> >> List Address: [email protected] >> >> Change listserver email address & settings: >> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> >> List-Archive: >> http://www.mail-archive.com/[email protected]/maillist.html >> >> List rules & etiquette: >> www.re-wrenches.org/etiquette.htm >> >> Check out or update participant bios: >> www.members.re-wrenches.org >> >> _______________________________________________ > List sponsored by Redwood Alliance > > List Address: [email protected] > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/[email protected]/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org > > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: [email protected] > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/[email protected]/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org > >
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