Hey Michael, Sorry to hear about your problems.
We have gone through several SMA SI issues that can be very difficult to narrow down but found most of the time the issues are founded on miss understanding the affects that different set points have on the over all system operation. In your system, I assume but want to confirm that the Sunny boys are set to off grid mode? And they have hardwired communications with Sunny Islands with the proper piggy back cards installed? We have two SMA SI offgrid system that we replaced lead acid batteries with LFP and are successfully operating both in open loop communications. Both are working well with minimal variation in SOC between SMA and batteries, both do have separate DC charging sources and therefore have external shunts enabled for monitoring the external charging sources (not sure if this plays a factor). Both are properly regulating the AC coupled PV, but took some adjustments to the SI charging parameters boost, full charge, float and equalize, to get it working well, as well as we found VRLA default battery SOC algorithm works better with LFP replacements. Also one point of note is on any new battery programing the system attempts to do a full charge and automatically sets battery SOC to 50%, how ever if everything is programmed correctly it should just raise the battery to its full voltage and hold it there, and it will then slowly auto correct the SOC. What did you set the max charge current for the batteries at? Have the batteries discharged over a night and does this still happen when the batteries are at a discharged state? If you want to talk through details, you can reach me on my cell, just be mindful of hawaii time. Aloha, Roland Shackelford President / Owner NABCEP PVIP #091209-162 O 808.775.7410 | M 808.938.9239 | 45-487 Lehua St Honokaa, HI 96727 Power Solutions for Generations Renewable Energy Services, Inc. <https://www.renewablenergy.com/> " Where there is integrity, there will be trust. Where there is trust, there will be an atmosphere for success." - Sadhguru On Tue, Oct 24, 2023 at 4:31 AM William Miller via RE-wrenches < re-wrenches@lists.re-wrenches.org> wrote: > Friends: > > > > This situation is as yet unresolved. It is complicated enough I created a web > page > <https://millersolar.com/MillerSolar/case_studies/36_SIFortress/36_SunnyIslandFortressIntegration.html> > to describe the scenario so I did not have to explain it over and over. I > submitted this to Fortress tech support. They said they had likely not > tested the Fortress compatibility with SI in an AC-Coupled system. > > > > While Fortress technicians and/or engineers ponder the situation I am > brainstorming solutions. One idea is to convert to a DC coupled system. > DC Charge controllers will have intrinsically better voltage control. The > charge controller most likely suitable is the Schneider 600 volt 100 amp > unit. I would need two of them. It is compatible with the existing string > wiring. In researching it many questions came up about that product’s > suitability. There is an integration guide for a Schneider system and > Fortress but this would be a mixed system of Schneider and SMA. Would I be > able to apply closed loop communication to both systems? Could the charge > controllers work in open loop? Has anyone tried anything like this? > > > > I will keep you apprised. > > > > William Miller > > > > Miller Solar > > 17395 Oak Road, Atascadero, CA 93422 > > 805-438-5600 > > www.millersolar.com > > CA Lic. 773985 > > > > > _______________________________________________ > 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 > >
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