Re: [RE-wrenches] Dual radian system stopping selling on sunny days

[Maverick Brown via RE-wrenches]

Great!  I was driving yesterday, and couldn’t find this document.  I had this issue pop up on a dual stack and found out the inverter charger had been turned off. Turned it back on via the Charger button on the MATE3S and BAM! Offset changed to Selling.  I set: SellRE = 53.6 CC.FLT = 54.4 CC.ABS = 55.2 I measure these at the battery and make adjustments (either in calibration settings or by changing the above numbers). Thank you, Maverick Maverick Brown Off-Grid Solar Commander since 2006 Maverick Solar Enterprises, Inc.  • Solar Commander Remote Power  • SunFlow Systems Cathodic Protection  maver...@mavericksolar.com 512-460-9825 On Sep 26, 2025, at 10:40 PM, Tyrone Houck via RE-wrenches <re-wrenches@lists.re-wrenches.org> wrote:  It's also worth considering temperature compensation and how that may affect the dynamic...also the CCs float and absorb should be set slightly higher than the inverters. Regarding offset behavior, here is an application note that may help.. https://outbackpower.com/downloads/documents/appnotes/offset_tech_note_correc.pdf     On Fri, Sep 26, 2025, 8:23 PM Tyrone Houck <tyroneho...@gmail.com> wrote: 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 <re-wrenches@lists.re-wrenches.org> 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  -- Dave Tedeyan, P.E. Owner | Sungineer Solar p: he | him | his a: 1653 Slaterville Rd. | Ithaca, NY 14850 w: www.sungineersolar.com c: (607) 270-0370 _______________________________________________ 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

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