A possible fix. You could run a DC relay on the SB PV input that would be voltage triggered to prevent the battery volts from getting higher than you want.
The SI has 2 aux relays I think? Or could do a tristar with RD-1 relay that has 4 channels. Just a thought jay > On May 7, 2024, at 11:11 PM, William Miller via RE-wrenches > <re-wrenches@lists.re-wrenches.org> wrote: > > Friends: > > I am still wrestling with problems integrating a Sunny Island / Sunny Boy AC > coupled system to a set of 5 E-vault Max battery cabinets. > > As a refresher, with closed loop comms, the Frequency Shift Power Control > system is not working, or not working quickly enough, and when nearing full > charge, the voltage can spike up to 66 volts and the SI system shuts down. > Fortress has told me in a roundabout way that they agree this is a real > problem and they are working on a solution. > > Another problem has reared its head: If the E-Vaults do not get charged > fully every 5 to 7 days, the BMS units SOC value becomes radically out of > calibration. The E-vault will report a higher SOC than is realistic. The SI > system starts the generator based on SOC and if the SOC is reported as high > the generator don’t start. Sooner rather than later the battery voltage gets > too low and the system shuts down. > > I have been tweaking on the settings like days-since-full-charge to attempt > to get this cycle to stop. No definitive answer yet. > > Here is the reason I am writing: Yesterday I could not get the Sunny Islands > to start. The battery voltage was 46 which should have been enough but for > some reason they just would not start. Because of this I could not charge > the batteries from generator or from AC coupled solar. I called SMA but they > told me they could not advise because of the non-compatible batteries. I > asked about the emergency charging procedure in the manual but I was told > this does not work with lithium batteries. The process is pretty scary > anyway so I was not inclined to try. > > SMA told me I may need an external 48 volt charging system. I have heard of > this being required in certain scenarios by wrenches. This would be a huge > pain in the ass: ordering one, waiting for it, hooking it up, etc. > > Here is what I did: I initiated the Quick Start Configuration mode and told > the SI system there was a new battery bank. I told it the bank was a very > small VRLA battery. The SI system accepted the 46 volts, started up and > allowed a generator charge. After an hour or so we reprogrammed the system > for lithium and problem resolved, at least for now. > > Hopefully this trick may help one of you some day. If it does, it was worth > my time typing it out. > > William > > Miller Solar > 17395 Oak Road, Atascadero, CA 93422 > 805-438-5600 > www.millersolar.com <http://www.millersolar.com/> > CA Lic. 773985 > > > _______________________________________________ > List sponsored by Redwood Alliance > > Pay optional member dues here: http://re-wrenches.org > <http://re-wrenches.org/> > > List Address: RE-wrenches@lists.re-wrenches.org > <mailto:RE-wrenches@lists.re-wrenches.org> > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > <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/ > <https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/> > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org> > > List rules & etiquette: > http://www.re-wrenches.org/etiquette.htm > <http://www.re-wrenches.org/etiquette.htm> > > Check out or update participant bios: > http://www.members.re-wrenches.org <http://www.members.re-wrenches.org/>
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