Larry, Could you possibly sketch out a rough schematic for what you are talking about here? It would help me understand your suggestion better. Thanks, Howie
Howie Michaelson NABCEP Certified Solar PV Installer™ Catamount Solar Renewable Energy Systems Sales and Service VT Solar Electric Incentive Partner http://www.CatamountSolar.com 802-272-0004 On Sep 25, 2015 12:18 PM, "Starlight Solar Power Systems" < la...@starlightsolar.com> wrote: > Hi Gary, > > That is exactly what I am considering. Because of the inconvenience of > reset and lack of automatic shutdown, I suggest the use of solenoids with > the Classic Aux control so the system will shut down the instant arc fault > is detected. It is easily reset from the battery location or anywhere you > wire the reset circuit. By supplying the coil voltage until the controller > takes over, the entire power system will restart; no trip to the roof. I > built a reset control using a simple wireless relay with a key fob remote > to perform the reset. Cost about $20. > > The Birdhouse requires human action, my idea does not but can be still be > activated by a person. Of course the Birdhouse offers many other shutdown > features for grid tie. But for a typical off grid installation, shutting > down the PV array and battery means all power is off at the source. If > there is a reason this will not work, I would like to know it. For a couple > hundred dollars, it seems like a cost effective and desirable approach. > > Larry > > > On Sep 24, 2015, at 8:51 PM, Gary Willett <g...@icarussolarservices.com> > wrote: > > Larry: > > The MidNite Solar 250A breakers used for battery bank disconnect, and the > breakers in the "Bird House" controlled roof-top mounted disconnecting > combiners, use a "shunt-trip" mechanism inside the circuit breaker. This > requires a manual reset to restore the disconnected circuits. This can be > inconvenient if the enclosure housing the shunt-trip breaker is not easily > accessible (i.e. on a two story house with a 6:12 roof pitch. Something to > consider. > > Regards, > > Gary Willett PE > Icarus Engineering > > > On 9/24/15 7:26 PM, Starlight Solar Power Systems wrote: > > William, Ray, > > I asked Midnite about using the Aux circuit for control for ground or arc > faults. They said this will (should) be added on the next firmware update. > This means if an arc fault is detected, the Classic will shut down AND > conductors leaving the array would be de-energized by switching off the HV > relay. All automatically. A second relay could be connected to the battery > for total system shutdown. Should be easy to build a circuit to re-energize > everything after a fault. > > Wouldn't this automatic method be better than waiting for someone to throw > a switch to shut things down? You would have to run the low voltage control > wire and perhaps put the relays in an enclosure. A disconnect switch could > be in series for manual shutdown. What am I missing? > > Larry > > > > On Sep 24, 2015, at 11:03 AM, Ray Walters < <r...@solarray.com> > r...@solarray.com> wrote: > > The other option is Midnite Solar's remote controlled breakers or combiner > boxes. They make up to a 250 amp breaker, but I found on large battery > systems that we need some thing larger. Colorado is now requiring Rapid > Disconnect for the batteries as well, which is NOT the original intent of > that article. Is the Gigavac UL listed? > > R.Ray Walters > CTO, Solarray, Inc > Nabcep Certified PV Installer, > Licensed Master Electrician > Solar Design Engineer303 505-8760 > > On 9/24/2015 10:45 AM, Starlight Solar Power Systems wrote: > > William and Wrenches, > > I have pondered situations like this one and wonder the following: If a > high voltage DC solenoid were placed at the PV array and the coil was > controlled by an arc fault detector along with a means of manually > disconnecting, would that not work to satisfy shut down requirements and > safety concerns? > > We have been using 350A, 800 volt solenoids from Gigavac in our lithium > battery system on both the positive and negative terminals (controlled by a > CPU) to provide 100% disconnect if case of any battery fault. > > Larry > > > > On Sep 23, 2015, at 2:26 PM, William Miller <will...@millersolar.com> > wrote: > > Dear Fellow Wrenches > > Below is a design conundrum that may resonate with some of you: > > We are finalizing a design for an off-grid residential system. The > customer insist the PV should be on the roof and pre-installed a 1-1/4” PVC > conduit from his roof to a crawl space, in anticipation of a solar > install. This created real problems, because we all know we can’t pull PV > source or output circuits in (or now, on) the envelopes of habitable > buildings. > > There was no practical way to replace the PVC. We contrived a method to > sleeve ¾” liquid-tight through the 1-1/4” PVC to the crawl space, > continuing on with EMT. This is the largest metallic conduit we could > fit. The distance was greater than 10 feet so we couldn’t use EMT. Due to > the conduit size restriction, we upgraded to Morningstar 600 volt charge > controllers, allowing us to reduce conductor size. > > (As a sidebar, although the Morningstar is listed as a 600 volt charge > controller, we have found no circumstance were we could take advantage of > that high a voltage. With the currently available high wattage modules, by > the time we added enough in series to get to 600 volts, we were well beyond > the wattage capabilities of the controller. For sake of design > considerations, I suggest one regard these units as ~300 volt charge > controllers.) > > We now have plans for 300 volt PV feeders running down an interior wall > and under the house, with no roof-top disconnecting means. It is my > understanding none are required. I am not comfortable with this. In this > scenario, there is no safe way to replace either of the two Morningstar > controllers. Should someone drill through or damage the EMT in the wall or > under the floor, there would be no way to turn off the feeder. > > I don’t like putting HU361RBs on a roof. They must remain vertical and so > they stick up too high and are hard to provide mounting for. Sola-deck > units are another option, but they require integrating with shingles, not > practical on this job or many others. I finally settled on a DC-Sunvolt > PV-X16A-4X-RG disconnect as a possible solution. At $216 it is not out of > range. The unit will provide means to turn off the feeders for service. I > will report back on my impressions of the unit. > > To distill this scenario, I don’t believe the code requires a disconnect, > but I feel morally obligated to install one. I’d be interested in > verification of the code interpretation and others response to similar > situations. > > I found no other options for rooftop disconnecting means that would be > small, reasonably priced and not present a high profile. If there are > products I don’t know about, I would be most grateful to receive your input. > > While researching the hardware I stumbled upon this article, linked > below. It seems to present a real dilemma, but I am not convinced. Please > remain skeptical as you read. It appears all of the links direct you to > the same source. > > > https://www.linkedin.com/pulse/greatest-debacle-solar-pv-australias-rooftop-dc-isolator-lucas-sadler > > Thanks again to all of you for helpful advice and expertise. I learned > about Sunvolt here, just one of many great suggestions. > > Sincerely, > > William Miller > > > <image002.jpg> > Lic 773985 > millersolar.com <http://www.millersolar.com/> > 805-438-5600 > > > > > > > > _______________________________________________ > 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 > > >
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