Forgive me if I'm missing something but typically I would have sell voltage slightly higher than float and lower than absorb.. I also never use the FNDC for charge termination and instead let the charge controller do everything by voltage... this may be a slightly different logic for lifepo4 but has always worked great for me for lead acid and agms. Best of luck!
On Fri, Sep 26, 2025, 10:52 AM Dave Tedeyan via RE-wrenches < [email protected]> wrote: > To the Outback extraordinaires, > > I've got a dual radian, grid tied system that has been in service for > about 9 years. Recently, it has started this behavior where it will stop > selling to the grid on sunny days. Looking back at the data, this has > happened intermittently and very infrequently a couple years ago. But now > we are at the point where it happens every sunny day. Once the batteries > get up to fully 100% charged (not 99%), the selling stops and the system > only harvests enough solar to cover the backed up loads. > > I got a hold of the USB card data. It appears that the inverter goes from > "Sell Enabled" to "Offset" when this happens. I cannot tell whether the > inverter randomly decides to switch mode and then stop selling, or whether > it is the stopping selling that puts it in "Offset" mode. The sell voltage > is set at 52V, and float is set to 54.4V. It looks like the batteries are > generally sitting around 54V when this happens. Once the inverter enters > "offset" mode, then the battery voltage stays steady at 54.0V > > Does anyone have any idea what can be causing this to happen? > Cheers, > Dave > > -- > > [image: Logo] <https://www.sungineersolar.com/> > Dave Tedeyan, P.E. > Owner | Sungineer Solar > p: he | him | his > a: 1653 Slaterville Rd. > <https://www.google.com/maps/search/1653+Slaterville+Rd.+%C2%A0+%7C%C2%A0Ithaca,+NY+14850?entry=gmail&source=g> > > <https://www.google.com/maps/search/1653+Slaterville+Rd.+%C2%A0+%7C%C2%A0Ithaca,+NY+14850?entry=gmail&source=g>| > Ithaca, > NY 14850 > <https://www.google.com/maps/search/1653+Slaterville+Rd.+%C2%A0+%7C%C2%A0Ithaca,+NY+14850?entry=gmail&source=g> > w: www.sungineersolar.com <http://www.sungineersolar.com/> > c: (607) 270-0370 > _______________________________________________ > List sponsored by Redwood Alliance > > Pay optional member dues here: http://re-wrenches.org > > List Address: [email protected] > > 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/[email protected]/ > 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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