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Nick,<br><br>
Where did you put the relay? I had problems breaking the AC out of
Sunny Boy inverters. <br><br>
Thanks,<br><br>
Drake<br><br>
<br>
At 07:58 PM 8/3/2009, you wrote:<br>
<blockquote type=cite class=cite cite="">Aloha Solar Bozos:<br>
I haven't posted here in ages, and I hope I am cutting
out the appropriate stuff? Probably not, but I will give it a
try. I want to reply to Topic 3 regarding backfeeding an off-grid
inverter with a grid-tied inverter.<br>
In 2004, I back-fed a SWR-2500U into an Outback FX
inverter's back-up power panel. It required a transformer to step
down to 120VAC and a voltage controlled relay to shut the Sunny Boy off
when the batteries were charged. Greg at OB said that the inverters
would regulate the AC output voltage at ~120V, so when the voltage would
rise up from the Sunny Boy's production, the FX was forced to take the
power in, resulting in the batteries being charged. You probably
realize that the Sunny Island controls the grid-tied inverter's output
but fluctuating the Hertz, which eliminated that issue for them.<br>
<br>
<font face="Tahoma" size=2><b>From:</b>
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<re-wrenches-request@lists.re-wrenches.org><br>
<b>To:</b> re-wrenches@lists.re-wrenches.org<br>
<b>Sent:</b> Monday, August 3, 2009 6:47:22 AM<br>
<b>Subject:</b> RE-wrenches Digest, Vol 2, Issue 818<br>
</font><br>
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<br>
Today's Topics:<br><br>
1. Re: AC Backfeed Battery Over-Charging (Jeff Yago)<br>
2. Broken Modules (Doug Wells)<br>
3. Re: AC Backfeed Battery Over-Charging (Tump)<br>
4. Re: Broken Modules (Jeff Yago)<br><br>
<br>
----------------------------------------------------------------------<br>
<br>
Message: 1<br>
Date: Mon, 3 Aug 2009 06:21:56 -0700<br>
From: "Jeff Yago"
<<a href="mailto:jryago@netscape.com">jryago@netscape.com</a>><br>
Subject: Re: [RE-wrenches] AC Backfeed Battery Over-Charging<br>
To: RE-wrenches
<<a href="mailto:re-wrenches@lists.re-wrenches.org">
re-wrenches@lists.re-wrenches.org</a>><br>
Message-ID:
<<a href="mailto:20090803062156.CD9B16AE@resin17.mta.everyone.net">
20090803062156.CD9B16AE@resin17.mta.everyone.net</a>><br>
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------------------------------<br><br>
Message: 2<br>
Date: Mon, 3 Aug 2009 09:32:08 -0400<br>
From: Doug Wells
<<a href="mailto:dwells@thesolarspecialists.com">
dwells@thesolarspecialists.com</a>><br>
Subject: [RE-wrenches] Broken Modules<br>
To:
<a href="mailto:RE-wrenches@lists.re-wrenches.org">
RE-wrenches@lists.re-wrenches.org</a><br>
Message-ID:<br>
<<a href="mailto:D6573665-38CE-4E54-A70F-F7AC8F630DF3@thesolarspecialists.com">
D6573665-38CE-4E54-A70F-F7AC8F630DF3@thesolarspecialists.com</a>><br>
Content-Type: text/plain; charset=US-ASCII; format=flowed<br><br>
Wrenches,<br><br>
I am curious what other installers are doing with broken modules?<br>
I know some manufacturers are starting recycling programs.<br><br>
<br>
Doug Wells<br>
The Solar Specialists<br>
Morrisville, VT 05661<br>
(p) 802-223-7014<br>
(c) 802-498-5856<br>
<a href="http://www.thesolarspecialists.com">
www.thesolarspecialists.com</a><br><br>
<br><br>
<br><br>
<br><br>
------------------------------<br><br>
Message: 3<br>
Date: Mon, 3 Aug 2009 09:39:21 -0400<br>
From: "Tump"
<<a href="mailto:tump@hughes.net">tump@hughes.net</a>><br>
Subject: Re: [RE-wrenches] AC Backfeed Battery Over-Charging<br>
To: <<a href="mailto:jryago@netscape.com">jryago@netscape.com</a>>,
"'RE-wrenches'"<br>
<<a href="mailto:re-wrenches@lists.re-wrenches.org">
re-wrenches@lists.re-wrenches.org</a>><br>
Message-ID: <CAFB0B2FF97B4386BB4EF00DF46766F9@tumpdggfbh2yn6><br>
Content-Type: text/plain; charset="us-ascii"<br><br>
Hey Jeff this was something that Greg @ OB was working on summer of
06.....<br>
Should have it tump, almost got it little problem .... Ahhh sorry we are
no<br>
longer working on that! I was in the middle of a large AC Coupled system
&<br>
had been waiting for 4 months for this "trick" soft ware to
come on line.<br>
Perhaps CF might be able to update us on this software. Kinda of a
no<br>
brainier perhaps, John B & the boys @ SMA patented this
"trick" software.<br><br>
<br>
<<a href="mailto:Tump@swnl.net" eudora="autourl">
mailto:Tump@swnl.net</a>>
<a href="mailto:Tump@swnl.net">Tump@swnl.net</a>
<<a href="http://www.swnl.net/" eudora="autourl">
http://www.swnl.net/</a>><br>
<a href="http://www.SWNL.net">www.SWNL.net</a><br>
Solarwinds
Northernlights <br>
Serving Mid Coast Maine & Northern California<br>
Me.# 207-832-7574 Cl.#
610-517-8401<br><br>
Blair "TUMP" May<br>
******** MAINE'S CHARTER
********<br>
NABCEP "Certified PV Installer" <br>
<br>
******** MAINE'S CHARTER
********<br>
Trace Xantrex "Certified" Dealer / Installer"<br>
<br>
<br><br>
-----Original Message-----<br>
From:
<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org">
re-wrenches-bounces@lists.re-wrenches.org</a><br>
[<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org" eudora="autourl">
mailto:re-wrenches-bounces@lists.re-wrenches.org</a>] On Behalf Of Jeff
Yago<br>
Sent: Monday, August 03, 2009 9:22 AM<br>
To: RE-wrenches<br>
Subject: Re: [RE-wrenches] AC Backfeed Battery Over-Charging<br><br>
<br>
I have a question that may be one of those that everyone wants to know
the<br>
answer but feel they are the only one that doesn't know the answer,
or<br>
perhaps I am the only one that doesn't know!. <br><br>
In an AC-coupled system, i.e. the 240 VAC output solar inverter mounted
at a<br>
distant array (240 VAC out to reduce long line loss) is wired to the
120/240<br>
VAC output emergency panel supplied from a battery based inverter.
This<br>
allows the solar inverter to stay up when the grid goes down since it
thinks<br>
the grid is still up on the load side of the battery based
inverter. The<br>
battery based inverter will use any excess backfed power from the
solar<br>
inverter that is in excess of the other supplied loads to re-charge
the<br>
battery. However, when this happens the battery charging process
can boil<br>
the batteries when there are no other loads running. <br><br>
I have been told this is because the battery based inverter does not<br>
regulate its charging of the battery when using backfed power from
its<br>
output panel, but I still don't understand why. If the battery
charger in<br>
the inverter can provide regulated 3-stage battery charging when the
power<br>
is supplied from the grid or a generator, why does it suddenly become a
full<br>
output un-regulated battery charger when power is supplied from backfeed
and<br>
will keep charging regardless of reaching a high battery
voltage? <br><br>
I would have assumed the battery charger section would charge the same
way<br>
regardless of where the power is being supplied from, or perhaps
just<br>
shutdown on some kind of backfeed safety. As far as I know,
this<br>
over-charging problem in an AC coupled dual inverter system is true for
all<br>
battery-based inverters. Any inverter techs out there that can
explain<br>
why? Perhaps this would be a nice feature in future high-end
battery-based<br>
inverters so we no longer need the custom power relay field wiring
to<br>
provide this high voltage cut-out?.<br><br>
Thanks,<br><br>
Jeff Yago<br><br>
<br><br>
_____ <br><br>
Netscape. Just the Net You Need.<br><br>
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------------------------------<br><br>
Message: 4<br>
Date: Mon, 3 Aug 2009 06:47:21 -0700<br>
From: "Jeff Yago"
<<a href="mailto:jryago@netscape.com">jryago@netscape.com</a>><br>
Subject: Re: [RE-wrenches] Broken Modules<br>
To: RE-wrenches
<<a href="mailto:re-wrenches@lists.re-wrenches.org">
re-wrenches@lists.re-wrenches.org</a>><br>
Message-ID:
<<a href="mailto:20090803064721.CD9B1303@resin17.mta.everyone.net">
20090803064721.CD9B1303@resin17.mta.everyone.net</a>><br>
Content-Type: text/plain; charset="UTF-8"<br><br>
We have only had one broken module due to shipping damage and this was
the bottom 200 watt module in a shipment where each 2 modules on the
pallet were in heavy cardboard shipping boxes. Of course this not
discovered for several weeks until we worked our way down the
stack. However, since suppliers like Evergreen have switched to the
plasic corners that allow stacking modules without any cardboard
packaging, we have had no more breakage in shipment. I assume the
fork truck drivers now see a large stack of glass and take a little more
care whenre thay ram the forks. <br><br>
As far as what we did with our broken module (which taught a very
expensive lesson about checking shipments), we keep it to show students
in our training classes what happens when things go wrong.<br><br>
Jeff Yago<br><br>
_____________________________________________________________<br>
Netscape. Just the Net You Need.<br><br>
<br>
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<x-sigsep><p></x-sigsep>
<font color="#0000FF">Drake Chamberlin<br>
Athens Electric<br>
OH License 44810<br>
CO License 3773<br>
NABCEP </font><font size=1 color="#0000FF">TM
</font><font color="#0000FF">Certified PV Installer <br>
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Mobile - 740-856-9648 </font></body>
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