<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD><TITLE>Off-Grid Sizing Case</TITLE>
<META content="text/html; charset=iso-8859-1" http-equiv=Content-Type>
<META name=GENERATOR content="MSHTML 8.00.6001.18852">
<STYLE></STYLE>
</HEAD>
<BODY bgColor=#ffffff>
<DIV><FONT face=Calibri>The rate of charging is not the real problem in most
undersized systems, it is the fact that the batteries seldom, if ever, get fully
charged. Given the ratio of PV vs battery capacity, I would suspect that their
batteries have been chronically undercharged for ages. We usually recommend
around 1 watt of pv per AH for a 12 volt system, 2 watts for 24 volt
etc.</FONT></DIV>
<DIV><FONT face=Calibri></FONT> </DIV>
<DIV><FONT face=Calibri>A generator is not usually the answer, because it may
have to run for hours to get that final 5-15% of charge into the batteries.
Generators are good for equalizing, not so much for general
charging.</FONT></DIV>
<DIV><FONT size=2 face=Calibri></FONT> </DIV>
<DIV>..................................................................................................<BR>Northern
Arizona Wind & Sun - Electricity From The Sun Since 1979<BR>Solar Discussion
Forum: <A
href="http://www.wind-sun.com/ForumVB/">http://www.wind-sun.com/ForumVB/</A><BR>..................................................................................................</DIV>
<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B>From:</B>
<A title=markf@berkeleysolar.com href="mailto:markf@berkeleysolar.com">Mark
Frye</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=re-wrenches@lists.re-wrenches.org
href="mailto:re-wrenches@lists.re-wrenches.org">'RE-wrenches'</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Thursday, December 03, 2009 10:56
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [RE-wrenches] Off-Grid
Sizing Case</DIV>
<DIV><BR></DIV>
<DIV dir=ltr align=left><SPAN class=531035617-03122009><FONT color=#0000ff
size=2 face=Arial>So being able to achieve C10 charging from the PV is not so
important?</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=531035617-03122009></SPAN><BR><SPAN
lang=en-us><FONT size=2 face=Arial>Mark Frye</FONT></SPAN> <BR><SPAN
lang=en-us><FONT size=2 face=Arial>Berkeley Solar Electric
Systems</FONT></SPAN> <BR><SPAN lang=en-us><FONT size=2 face=Arial>303 Redbud
Way</FONT></SPAN> <BR><SPAN lang=en-us><FONT size=2 face=Arial>Nevada
City, CA 95959</FONT></SPAN> <BR><SPAN lang=en-us><FONT size=2
face=Arial>(530) 401-8024</FONT></SPAN> <BR><SPAN lang=en-us></SPAN><A
href="http://www.berkeleysolar.com"><SPAN lang=en-us><U><FONT color=#0000ff
size=2 face=Arial>www.berkeleysolar.com</FONT></U></SPAN></A><SPAN
lang=en-us><FONT size=2 face=Arial> </FONT></SPAN> </DIV>
<DIV> </DIV><BR>
<DIV dir=ltr lang=en-us class=OutlookMessageHeader align=left>
<HR tabIndex=-1>
<FONT size=2 face=Tahoma><B>From:</B> <A
href="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</A>
[mailto:re-wrenches-bounces@lists.re-wrenches.org] <B>On Behalf Of </B><A
href="mailto:Windsun@wind-sun.com">Windsun@wind-sun.com</A><BR><B>Sent:</B>
Thursday, December 03, 2009 9:51 AM<BR><B>To:</B>
RE-wrenches<BR><B>Subject:</B> Re: [RE-wrenches] Off-Grid Sizing
Case<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV><FONT size=2 face=Calibri>I would go with #1. The solar is obviously
undersized for the battery bank he has. Another panel + MPPT should give him
about 25-40% more, depending on temps etc.</FONT></DIV>
<DIV><FONT size=2 face=Calibri></FONT> </DIV>
<DIV>..................................................................................................<BR>Northern
Arizona Wind & Sun - Electricity From The Sun Since 1979<BR>Solar
Discussion Forum: <A
href="http://www.wind-sun.com/ForumVB/">http://www.wind-sun.com/ForumVB/</A><BR>..................................................................................................</DIV>
<P>
<HR>
<P></P>_______________________________________________<BR>List sponsored by
Home Power magazine<BR><BR>List Address:
RE-wrenches@lists.re-wrenches.org<BR><BR>Options &
settings:<BR>http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org<BR><BR>List-Archive:
http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org<BR><BR>List
rules & etiquette:<BR>www.re-wrenches.org/etiquette.htm<BR><BR>Check out
participant
bios:<BR>www.members.re-wrenches.org<BR><BR></BLOCKQUOTE></BODY></HTML>