I like where your going with this Jason On Sat, Feb 22, 2025 at 5:08 AM Jason Szumlanski via RE-wrenches < [email protected]> wrote:
> I have been thinking a lot recently about the reasons off-grid systems can > shut down, and working on strategies to prevent these nuisances that > require manual intervention. > > Ideally, a BMS should never shut down due to low voltage/SOC because a > properly programmed inverter should reach it's cut off well before the BMS > decides it needs to protect the battery, especially where there is closed > loop communication. But let's say that happens, where the BMS does make the > DC battery output go to zero. > > It seems to me like the inverter should be able to start a generator, and > then signal to the BMS that a charging source is available. But I'm not > aware of any system that actually does this. The inverter should be able to > wake up the battery. I can see this being particularly possible where one > manufacturer is writing the code (I'm thinking Midnite AIO/Powerflo). > > Of course, the inverter would have to have power in order to do that, so > if it's nighttime and there is no PV, the inverter power would need to come > from somewhere. I have two thoughts. First, someone could manually start > the generator, waking up the inverter, but they would not have to reset the > BMS if the inverter told it to wake up. The second way would be for the > inverter to somehow close the 2-wire start circuit upon inverter shutdown, > restoring power to the inverter automatically. > > If those are not options, an external NO relay powered by the inverter > output could be added to the 2-wire start circuit, perhaps with a time > delay to return to the NO position to allow the generator to remain powered > until the inverter does it's thing and starts charging the batteries. > > Anyway, my question is whether any inverter/battery combination out there > works in a way that the inverter tells the battery there is a charging > source available to wake up the BMS and reconnect DC power. And if not, why? > > Jason Szumlanski > Florida Solar Design Group > _______________________________________________ > 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 > > -- Michael Morningstar Morningstar Electric Inc PO Box 1494 Mount Shasta, CA 96067 530-921-0560 CSLB 1116835 [email protected]
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