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<DIV><SPAN class=640213313-03082009><FONT face=Arial color=#0000ff size=2>Hey
Jeff this was something that Greg @ OB was working on summer of 06..... Should
have it tump, almost got it little problem .... Ahhh sorry we are no longer
working on that! I was in the middle of a large AC Coupled system & had been
waiting for 4 months for this "trick" soft ware to come on line. Perhaps CF
might be able to update us on this software. Kinda of a no brainier perhaps,
John B & the boys @ SMA patented this "trick" software.</FONT></SPAN></DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV align=left> <A
href="mailto:Tump@swnl.net"><STRONG>Tump@swnl.net</STRONG></A><FONT
face=Arial> <SPAN class=597035700-05092007><FONT
face="Times New Roman"> <FONT
color=#0000ff><U><A
href="http://www.swnl.net/"><STRONG>www.SWNL.net</STRONG></A></U></FONT></FONT></SPAN></FONT><BR> <FONT
color=#0000ff><SPAN
class=597035700-05092007> </SPAN><SPAN
class=597035700-05092007><FONT size=5>Solarwinds
Northernlights</FONT></SPAN></FONT> </DIV>
<DIV align=left><STRONG><EM> Serving Mid Coast Maine & Northern
California<BR> Me.# 207-832-7574 Cl.#
610-517-8401</EM></STRONG></DIV>
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<DIV
align=left><EM><STRONG>
<FONT color=#0000ff>Blair "TUMP" May</FONT></STRONG></EM></DIV>
<DIV align=left><STRONG><EM> ********
MAINE'S CHARTER ********<BR> <FONT
color=#008000> <U>
NABCEP "Certified PV
Installer"</U></FONT></EM></STRONG><STRONG><EM><U> <BR></U>
<BR> ******** MAINE'S CHARTER
********<BR> </EM></STRONG><STRONG><EM><FONT color=#008000><U>Trace
Xantrex "Certified" Dealer / Installer"<BR></U></FONT>
</EM></STRONG></DIV>
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<DIV></DIV>
<DIV class=OutlookMessageHeader lang=en-us dir=ltr align=left><FONT
face=Tahoma size=2>-----Original Message-----<BR><B>From:</B>
re-wrenches-bounces@lists.re-wrenches.org
[mailto:re-wrenches-bounces@lists.re-wrenches.org] <B>On Behalf Of </B>Jeff
Yago<BR><B>Sent:</B> Monday, August 03, 2009 9:22 AM<BR><B>To:</B>
RE-wrenches<BR><B>Subject:</B> Re: [RE-wrenches] AC Backfeed Battery
Over-Charging<BR><BR></FONT></DIV>
<DIV style="FONT-SIZE: 10pt; FONT-FAMILY: Arial, sans-serif">
<DIV>I have a question that may be one of those that everyone wants to know
the answer but feel they are the only one that doesn't know the answer, or
perhaps I am the only one that doesn't know!. </DIV>
<DIV> </DIV>
<DIV>In an AC-coupled system, i.e. the 240 VAC output solar inverter mounted
at a distant array (240 VAC out to reduce long line loss) is wired
to the 120/240 VAC output emergency panel supplied from a
battery based inverter. This allows the solar inverter to stay
up when the grid goes down since it thinks the grid is still up on the load
side of the battery based inverter. The battery based inverter will
use any excess backfed power from the solar inverter that is in
excess of the other supplied loads to re-charge the battery.
However, when this happens the battery charging process can boil the batteries
when there are no other loads running. </DIV>
<DIV> </DIV>
<DIV>I have been told this is because the battery based inverter does not
regulate its charging of the battery when using backfed power from
its output panel, but I still don't understand why. If the battery
charger in the inverter can provide regulated 3-stage battery charging when
the power is supplied from the grid or a generator, why does it suddenly
become a full output un-regulated battery charger when power is supplied
from backfeed and will keep charging regardless of reaching a high
battery voltage? </DIV>
<DIV> </DIV>
<DIV>I would have assumed the battery charger section would charge the same
way regardless of where the power is being supplied from, or perhaps just
shutdown on some kind of backfeed safety. As far as I know, this
over-charging problem in an AC coupled dual inverter system is true for all
battery-based inverters. Any inverter techs out there that can
explain why? Perhaps this would be a nice feature in future
high-end battery-based inverters so we no longer need the custom power relay
field wiring to provide this high voltage cut-out?.</DIV>
<DIV> </DIV>
<DIV>Thanks,</DIV>
<DIV> </DIV>
<DIV>Jeff Yago</DIV><BR> <BR>
<HR>
Netscape. Just the Net You Need.</DIV></BLOCKQUOTE></BODY></HTML>