Id recommend taking the generator start duties away from the sunny Island if you don't have a BMS that can communicate.
Id recommend using a Victron Ekrano (or whichever gx device) coupled with a smart shunt to measure current flow and calculate state of charge. This can calculate soc nicely and start your generator. It can also be accessed remotely. As far as I know, there is no setting that can allow the soc on the Sunny Island to be accurate with lithium. Good luck Mac Lewis *"Yo solo sé que no sé nada." -Sócrates* On Fri, Sep 11, 2026, 4:38 PM Jerry Shafer <[email protected]> wrote: > Wrenches, > I've done a few SI to Li set ups, One must do is to eliminate the BTS with > resistor to get 75⁰F > Funtimes > > On Fri, Sep 11, 2026, 10:15 AM Lou Russo <[email protected]> > wrote: > >> What brand of batteries are you using? >> >> There is no way to get an accurate SOC on an SI paired with lithium >> batteries without closed-loop comms nor is there a means to adjust voltage >> setpoints for generator start. >> >> Every decision the SI makes is based on SOC. >> >> As far as I can tell, when selecting the battery type >> when commissioning the SI, it loads pre-determined setting (none of which >> are documented) that SMA has decided on and they can not be changed. So if >> you select FLA or VRLA and use lithium it will never work quite right. >> >> The only lithium batteries I have every used with a SI is Discover Energy >> lithium batteries and their Lynk 2. So my experience is limited in this >> regard but the combo works well for me. >> Lead-acid batteries also work great. >> >> The SI is a unique beast. Programming it is very different from other >> inverters from that time period. >> >> Lou Russo >> Owner >> [email protected] >> Office - 808 345 6762 >> Direct Line - 808 731 1907 >> Spree Solar Systems LLC >> CT-34322 >> >> >> >> On Fri, Sep 11, 2026 at 4:04 AM Jim Gowdy <[email protected]> >> wrote: >> >>> Good Morning, >>> I've integrated some lithium battery cells to a single Sunny Island >>> inverter (model SI4548-US-10) and I'm having an issue with the Sunny >>> Island's SOC. My batteries will be at pretty much full charge and the >>> inverter will show something like 50% SOC and it's causing me problems of >>> starting the generator prematurely and one time it shut the system down. I >>> am still looking through the manual, but I was wondering if there is a way >>> to calibrate the state of charge or use battery voltage for my setpoints. >>> I'm timid to call their tech support because these batteries are not on >>> their approved list. Any input would be appreciated. >>> >>> -- >>> Jim with Gowdy Electric >>> Cambria, Ca 93428 >>> business 805 927 2630 <(805)%20927-2630> >>> cell 805 975 5279 <(805)%20975-5279> >>> _______________________________________________ >>> 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 >>> >> _______________________________________________ >> 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 >> > _______________________________________________ > 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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