I agree with everything Ray has said when you're using a system with lead-acid batteries, however this doesn't apply to lithium-ion. Li batteries don't need multistage charging like LA batteries do so they would be a perfect fit for a retro-fit battery backup system that can only bulk charge.
I'd also suggest people check out the Enphase IQ8 system which allows the inverters to operate without the grid with no storage. They should also be able to black start an AC coupled system with no grid unlike other AC coupled designs. I haven't seen it in person but two of my co-workers toured their demo project and it seems to live up to everything Enphase is claiming. Thanks, Will On Wed, Sep 12, 2018 at 8:38 PM Ray <r...@solarray.com> wrote: > I didn't watch the whole thing, but it looked like a standard AC couple > set up with an Outback Radian. My understanding is that Outback no longer > supports AC Coupling, BTW. I would never use that for an off grid system > or for longer outages. In a very brief explanation, it essentially > bypasses any charge controlling to the batteries, and puts full Array power > into the batteries until a relay (or phase shifting) disconnects the > array. No three stage charging, no taper charging, no float, no temp > compensation. Its like trying to fill a 5 gal bucket with a fire house, or > drive a car with a throttle that's either off or at full throttle, no in > between. The other issue is that if the batteries get low and the inverter > shuts off, the system will not recharge, and after a couple of weeks the > batteries will be sulfated beyond recovery. > > My guess is that manus that advocated this approach got into trouble from > end users that fried expensive battery banks during longer outages. I > would consider it the equivalent of cheap backup generators: a great backup > system for folks that don't need it. There are probably thousands of > those out there with happy customers and installers, because its never > actually been used for more than a few hours, and the batteries are > properly charged from the grid 99.8% of the time. > > Ray Walters > Remote Solar > 303 505-8760 > > On 9/12/18 6:11 PM, Ken Schaal wrote: > > https://www.youtube.com/watch?v=eyhkIfS5Z-Q > > > _______________________________________________ > List sponsored by Redwood Alliance > > 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 > > List-Archive: > http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html > > List rules & etiquette:www.re-wrenches.org/etiquette.htm > > Check out or update participant bios:www.members.re-wrenches.org > > > _______________________________________________ > List sponsored by Redwood Alliance > > 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 > > List-Archive: > http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org > > -- *Will White* Curriculum Developer e: w...@solarenergy.org w: www.solarenergy.org p: 802-272-3092 PV Installation Professional # 093006-34 *FACT: If we covered 0.33% of the earth with solar panels, we could power the world with renewable energy.* Do you envision a world powered by renewable energy? Be the change <http://solarenergy.org/donate>.
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