<html><body><div style="color:#000; background-color:#fff; font-family:arial, helvetica, sans-serif;font-size:12pt"><div style="RIGHT: auto"><SPAN style="RIGHT: auto">I would guess that it depends upon the use cycle, you always put more electrons back in than you take out, If you are assuming a 90% recharge efficiency recharging once every three days, a few percent of the recharge excess energy could be used. BUT I strongly agree I have seen too many problems with taped battery banks so avoid is the first rule. </SPAN></div>
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<div style="RIGHT: auto"><SPAN style="RIGHT: auto">This would make an interesting measurement. <VAR id=yui-ie-cursor></VAR> </SPAN></div>
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<DIV style="BORDER-BOTTOM: #ccc 1px solid; BORDER-LEFT: #ccc 1px solid; PADDING-BOTTOM: 0px; LINE-HEIGHT: 0; MARGIN: 5px 0px; PADDING-LEFT: 0px; PADDING-RIGHT: 0px; HEIGHT: 0px; FONT-SIZE: 0px; BORDER-TOP: #ccc 1px solid; BORDER-RIGHT: #ccc 1px solid; PADDING-TOP: 0px" class=hr contentEditable=false readonly="true"></DIV><B><SPAN style="FONT-WEIGHT: bold">From:</SPAN></B> mac Lewis <maclewis1@gmail.com><BR><B><SPAN style="FONT-WEIGHT: bold">To:</SPAN></B> RE-wrenches <re-wrenches@lists.re-wrenches.org><BR><B><SPAN style="FONT-WEIGHT: bold">Sent:</SPAN></B> Thursday, September 1, 2011 3:59 PM<BR><B><SPAN style="FONT-WEIGHT: bold">Subject:</SPAN></B> Re: [RE-wrenches] unique battery bank design question<BR></FONT><BR>
<DIV id=yiv886278210>Glad I asked! Do these converters have a decent expected lifetime? If anyone has any good DC-DC converters to peddle, please contact me off list.
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<DIV>Thanks for the help. <BR><BR>
<DIV class=yiv886278210gmail_quote>On Thu, Sep 1, 2011 at 2:48 PM, Jason Szumlanski <SPAN dir=ltr><<A href="mailto:Jason@fafcosolar.com" rel=nofollow target=_blank ymailto="mailto:Jason@fafcosolar.com">Jason@fafcosolar.com</A>></SPAN> wrote:<BR>
<BLOCKQUOTE style="BORDER-LEFT: #ccc 1px solid; MARGIN: 0px 0px 0px 0.8ex; PADDING-LEFT: 1ex" class=yiv886278210gmail_quote>1a x 12V x 24hrs = 288 watt-hours on a 48,000 watt-hour battery. My math<BR>shows 0.6% of the nominal capacity. And that assumes there is no<BR>charging source present.<BR><BR>That being said, I would agree that avoiding it altogether is the wise<BR>decision, but there has to be a level at which the tapped load is<BR>inconsequential. I'm just curious what that level is!<BR><BR>Jason Szumlanski<BR>Fafco Solar<BR>
<DIV class=yiv886278210im><BR><BR>-----Original Message-----<BR>From: <A href="mailto:re-wrenches-bounces@lists.re-wrenches.org" rel=nofollow target=_blank ymailto="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</A><BR></DIV>[mailto:<A href="mailto:re-wrenches-bounces@lists.re-wrenches.org" rel=nofollow target=_blank ymailto="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</A>] On Behalf Of Hugh<BR>Sent: Thursday, September 01, 2011 4:21 PM<BR>To: RE-wrenches<BR>Subject: Re: [RE-wrenches] unique battery bank design question<BR>
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<DIV class=yiv886278210h5><BR>At 15:57 -0400 1/9/11, Jason Szumlanski wrote:<BR><BR>> A 1A @ 12V fan on a 1000aH @48V battery bank can't make any real<BR>>difference. Correct me if I am wrong!<BR>><BR><BR>Yes that is wrong, because after 4 days you have removed 10% of the<BR>nominal capacity or about 20% of the usable capacity.<BR><BR>Tapping off batteries is bad practice as universally agreed. One way<BR>to mitigate it could be to use separate shunt regulators (diversion<BR>load controllers) for each 12-volt portion. This would probably be a<BR>healthy feature for 'balancing' any 48 volt battery and would<BR>possibly rescue a tapped battery, given enough surplus energy<BR>availability (which is usually the key thing for battery health).<BR><BR>Just a thought.<BR><BR>The snag is the cost. ho hum.<BR>--<BR>Hugh Piggott<BR><BR>Scoraig<BR><A href="http://www.scoraigwind.co.uk/" rel=nofollow
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<DIV><BR></DIV>Mac Lewis<BR><BR><SPAN style="COLOR: rgb(255,153,0); FONT-SIZE: medium"><B><FONT size=3 face="Arial, Helvetica, sans-serif">
<div align=left><FONT color=#000000 face="Verdana, Arial, Helvetica, sans-serif"><SPAN style="FONT-SIZE: small"><SPAN style="FONT-FAMILY: arial; COLOR: rgb(48,90,120); FONT-WEIGHT: normal"><FONT face="'times new roman', serif">"Yo solo sé que no sé nada." </FONT><SPAN style="COLOR: rgb(104,104,104); FONT-WEIGHT: 700"><FONT face="'times new roman', serif">-Sócrates</FONT></SPAN></SPAN></SPAN></FONT></div></FONT></B></SPAN><BR></DIV></DIV><BR>_______________________________________________<BR>List sponsored by Home Power magazine<BR><BR>List Address: <A href="mailto:RE-wrenches@lists.re-wrenches.org" ymailto="mailto:RE-wrenches@lists.re-wrenches.org">RE-wrenches@lists.re-wrenches.org</A><BR><BR>Options & settings:<BR><A href="http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org" target=_blank>http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org</A><BR><BR>List-Archive: <A
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