Regarding the DC disco issue, we have identified the 3-pole, 600Vdc rated, 200A Crouse-Hinds CH364R ( http://www.crouse-hinds.com/crousehinds/newproducts/relatedinfo/Solar%20Combiner%20Brochure%20110309.pdf) as a replacement for the Square D version. Its a little pricey but it looks like the best available option these days. We are also looking at the SolarBOS disconnecting combiners - does anyone have any experience with them?
Andrew Truitt Standard Solar Inc. On Wed, Apr 14, 2010 at 3:07 AM, Philip Boutelle <philboute...@gmail.com>wrote: > Kirpal and Wrenches, > > Can you describe your battery setup with the four Sunny Islands? SMA > recommends using two parallel 1/0 conductors to each SI DC disconnect, for > three reasons: wire fill limitations with the 1.5" knockouts they provide, > ease of landing in the breaker, and because the 125A breaker is > double-barreled and rated for 125A on each leg with the current flow not > necessarily symmetric, so you need a rating of approx. 200A on the parallel > conductors (I'm quoting Martin and Antonio at SMA here, this detail is not > in the manual but what they recommended to me as best practice. The manual > at one point lists "2 x 1AWG" for the DC connections, nothing further). > > With four SIs, that's eight positive and eight negative 1/0 conductors to > be bussed from the battery bank, or at least to the SIs. I have a similar > project coming up and am looking at a custom fuse/bus block from Deltec > <http://www.deltecco.com/>to arrange/distribute those wires, but would > love to hear other ideas and experiences on how to go from a single string > of 48V batteries, through a fused DC disconnect, and then land in the 4 SIs. > > > The fused DC disconnect is also an issue; with 20kW of rated continuous > power at a worst-case of 41V (numbers from the spec sheets), that's 487A > *1.25 = 610A. I could break that up into four parallel conductors, enabling > me to use a 4-pole 200A disconnect w/ 175A fuses (space is an issue on the > mechanical wall). But do I need to pass the DC conductors through two > switches on the disconnect to maintain the DC rating on the switch? And if > so, should I instead use a 4-pole 400A disco with 350A fuses and double > pass-through on the two positive conductors connecting to the battery bank? > Or.... ? > > Phil Boutelle > > Project Engineer > NABCEP Certified Solar PV Installer TM > Real Goods Solar, Inc. > > 831.477.0943 office > 831.359.5268 mobile > > 831.477.0944 fax > www.RealGoodsSolar.com <http://www.iesolar.com/> > > > > On Sun, Apr 11, 2010 at 7:44 PM, Kirpal Khalsa <solarwo...@gmail.com>wrote: > >> Dave----this is exactly what the sunny island is capable of.....supply the >> house panel from the sunny island output, and the main panel in the barn to >> the input side, the house panel will run full time via the sunny islands, >> install a MANUAL transfer switch for times when the sunny islands may need >> to be turned off or removed for maintenance, I can't remember all the >> parameters of the programable relays in the sunny island but more than >> likely one of them is a warning, possibly to notify of no AC source. also >> you can pass power thru the relays in the sunny islands so no external relay >> is required. the beautiful thing about the sunny island/sunny boy set up >> is you actually are able to get a full multi stage charge process on your >> batteries during a power outage unlike most other AC coupled combinations >> which are simply a charge or no charge, taper not included. >> there are 2 programmable relays on each sunny island so in a dual inverter >> system you still have other relays available for other things like battery >> room fan control, or gen start. >> we have a similar system to yours up and running using 4 sunny islands >> and 4 sunny boys, flawlessly so far...... >> good luck.. >> For technical help or advice for your system I strongly recommend talking >> to Tucker in the service department over at SMA.......he knows the ac >> coupling set up, and system commissioning steps really well and will be able >> to make your job easy..... >> >> -- >> Sunny Regards, >> Kirpal Khalsa >> >> NABCEP Certified Solar PV Installer >> Renewable Energy Systems >> www.oregonsolarworks.com >> 541-218-0201 m >> 541-592-3958 o >> >> >> 2010/4/11 Richard L Ratico <richard.l.rat...@valley.net> >> >> Hi Dave, >>> >>> Depending on the house loads, you might very well do without an >>> additional (very >>> expensive) auto transfer switch. The inverters, of course, already have >>> one. >>> Just leave the Sunny Islands connected 24/7. The transfer from grid to >>> battery >>> is then milliseconds and flawless. The 56 amps continuous, and deep SI >>> surge >>> capacity will most likely, comfortably, handle the whole shebang. I've >>> got a >>> single SI5048 doing this now through a transformer. Works great. >>> >>> Put a manual transfer switch at the barn in the event there's ever a >>> problem >>> with the SI's. But, Iota makes a 100 Amp auto transfer switch, if you >>> decide >>> you've got to have one. It is attractively priced compared to anything >>> else I >>> could find. Beware, it may not be UL listed. I've got one, haven't used >>> it yet. >>> Let me know if you're interested :-) >>> >>> During a recent severe weather event, our customer's utility was down for >>> 5 >>> days. Battery lasted 24 hours before shutting down the system to >>> self-protect, >>> as designed and programmed. We had to round up a generator in a hurry to >>> "backup >>> the backup". A previously installed a manual transfer switch, with the >>> exterior >>> generator inlet, made that relatively painless, but it was something we >>> hoped >>> would never be needed. As you know, you also need SMA communication >>> boards and >>> the SMA programming cable to get the Sunny Boy to work with the SI's when >>> the >>> grid is down. >>> >>> Regards, >>> Dick Ratico >>> Solarwind Electric >>> >>> >>> I >>> >>> --- You wrote: >>> We have a new (for us) application for grid connected net-metered PV with >>> battery back-up as follows. The twist is that the entire load center in >>> the >>> house will be the "protected loads panel". >>> >>> - 5kW PV ground mount located 250 feet East of their barn. >>> >>> - Will utilize AC Coupled SB5000US inverter to (2)Sunny Island >>> 5048's for 120/240VAC back-up capability with 24.5kWh back-up battery >>> bank. >>> All inverters/batteries to be located in barn. >>> >>> - Barn has 200A service from grid (PV system AC point of >>> connection >>> will be there), house is located 175 feet West of barn and has a 100A >>> load >>> center (sub panel from barn). >>> >>> - Intention is to back up house as the protected loads panel fed >>> by >>> the Sunny Islands in case of grid failure. >>> >>> - The Sunny Islands will be able to pass through up to 56 Amps >>> at >>> 240VAC. >>> >>> - I want to supply the 100A house load center with up to 100A >>> during normal operation with grid available. I am proposing to use an >>> automatic contactor/transfer switch to feed the 100A house load center. >>> Normally Closed contacts from grid power, N.O. contacts fed by Sunny >>> Island. >>> Therefore normal operation will be for grid to be connected directly to >>> house 100A load center and under grid failure the transfer switch will >>> connect the Sunny Islands to power the 100A house load center. Under grid >>> failure condition we will have an LED signal light come on to warn the >>> homeowners that they are on battery power. >>> >>> Questions for wrenches: >>> >>> 1) Is that whole thing a viable idea? >>> >>> 2) 100 Amp automatic transfer switch recommendations? >>> >>> 3) LED signal light recommendations? Or is there another method to >>> warn homeowner of grid down status? >>> >>> >>> >>> Thanks, >>> >>> >>> >>> Dave >>> >>> >>> >>> David Palumbo, NABCEP Certified PV Installer >>> --- end of quote --- >>> _______________________________________________ >>> List sponsored by Home Power magazine >>> >>> List Address: RE-wrenches@lists.re-wrenches.org >>> >>> Options & settings: >>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >>> >>> List-Archive: >>> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org >>> >>> List rules & etiquette: >>> www.re-wrenches.org/etiquette.htm >>> >>> Check out participant bios: >>> www.members.re-wrenches.org >>> >>> >> >> >> >> >> _______________________________________________ >> List sponsored by Home Power magazine >> >> List Address: RE-wrenches@lists.re-wrenches.org >> >> Options & settings: >> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> >> List-Archive: >> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org >> >> List rules & etiquette: >> www.re-wrenches.org/etiquette.htm >> >> Check out participant bios: >> www.members.re-wrenches.org >> >> >> > > _______________________________________________ > List sponsored by Home Power magazine > > List Address: RE-wrenches@lists.re-wrenches.org > > Options & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out participant bios: > www.members.re-wrenches.org > > > -- "Don't get me wrong: I love nuclear energy! 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