Design Challenge (Was Sunny Island Experience?) [RE-wrenches]

[Jeff Clearwater]

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Hey Jay,

Yes, I've been following this configuration for a while now (Dave K., 
Sam V.and many others), just wanted to make sure you were not talking 
some specific limitation of the VFX as opposed to a GTFX when in 
off-grid mode.

And yes one must use the software modified SB - usually modified for 
the Sunny Island - with the higher voltage and frequency parameters.

And with more than one SB feeding into a FX stack, one could 
accomplish the rough equivalent of staged charging by having 
different VFX relays control each SB shutoff at slightly higher 
voltages as a charge limit set parameter.  Anyone see any problems 
with this?  Anyone try it and have pointers?

What relays are you using?  With SB2500s you are just switching 12 
amps at 240VAC - but I would want higher reliability than many of the 
DIN Rail mounted relays out there.  Suggestions?  I'll have about 
750' between my SBs and FXs - so I'll probably go with 120 or 240 
volt relay coils.  What did you use?

Thanks again!

Jeff C.


>-
>
>HI Jeff,
>
>No I'm talking full off grid.
>The system works pretty much the same way as the sunny island.
>
>You hook up the ( for example ) sonny boy into the output leads of 
>the VFX off grid version.  The power from the SB will go either to 
>the loads and/or battery charge by running the VFX backwards.
>
>The reason for changing the setpoints on the SB's is big motor 
>starts might drop the "grid voltage" below its connect point and so 
>it will drop off line.  But you can get them modified with, wider 
>voltage and hz windows, reduced time off line to make the system 
>work much better.
>
>The SB's will go off line if the VFX's shut down, no ac to sink to.  
>So the only concern is that the batteries are all full.  So you want 
>to turn off the SBs.  Best way is with  a solid state relay, between 
>the output of the SB and the connection to the VFX/power center.  It 
>shuts off when the batteries are too full, thats it.
>
>jay
>
>
>On Feb 4, 2006, at 9:07 PM, Jeff Clearwater wrote:
>
>>Hey Jay,
>>
>>Thanks for that,  However you said grid-tied version - did you mean 
>>the SB or in a grid-tied system?.  This is off-grid.  No utility on 
>>the other side of that isolation relay!.  Still work?
>>
>>Thanks again!
>>
>>Jeff
>>
>>
>>>
>>>Hi Jeff,
>>>
>>>I have talked to J. Berdner at SMA, and Chris F. at Outback  and 
>>>there is no problem with using the Sunny Boy into the Outbacks.  
>>>Should work with any grid tie version, but the folks at SMA can 
>>>work with you to tweek some of the settings so the line tie 
>>>inverters don't trip off line unnecessarily.
>>>( I've looked into this for a similar project)
>>>
>>>The only problem would occur if the batteries were full and there 
>>>was nowhere for the power to go.
>>>To get around this use some solid state relays, controlled via the 
>>>VFX's to shut off the SB's if the battereis get too full.
>>>
>>>Given that you are now at 500v from the array, better to move the 
>>>inverters to where you want them.
>>>
>>>Good luck,
>>>
>>>jay
>>>
>>>peltz power
>>>
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>>
>>
>>--
>>~~~~~~~~~~~~~
>>Jeff Clearwater
>>Village Power Design Associates
>>Sustainable Energy & Water Solutions for Home & Village
>>http://www.villagepower.com
>>gosolar at villagepower.com
>>
>>530-470-9166
>>877-SOLARVillage
>>877-765-2784
>>425 Nimrod St.
>>Nevada City, CA 95959
>>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~`~
>>
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-- 
~~~~~~~~~~~~~
Jeff Clearwater
Village Power Design Associates
Sustainable Energy & Water Solutions for Home & Village
http://www.villagepower.com
gosolar at villagepower.com

530-470-9166
877-SOLARVillage
877-765-2784
425 Nimrod St.
Nevada City, CA 95959
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~`~

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