<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:x="urn:schemas-microsoft-com:office:excel" xmlns:p="urn:schemas-microsoft-com:office:powerpoint" xmlns:a="urn:schemas-microsoft-com:office:access" xmlns:dt="uuid:C2F41010-65B3-11d1-A29F-00AA00C14882" xmlns:s="uuid:BDC6E3F0-6DA3-11d1-A2A3-00AA00C14882" xmlns:rs="urn:schemas-microsoft-com:rowset" xmlns:z="#RowsetSchema" xmlns:b="urn:schemas-microsoft-com:office:publisher" xmlns:ss="urn:schemas-microsoft-com:office:spreadsheet" xmlns:c="urn:schemas-microsoft-com:office:component:spreadsheet" xmlns:odc="urn:schemas-microsoft-com:office:odc" xmlns:oa="urn:schemas-microsoft-com:office:activation" xmlns:html="http://www.w3.org/TR/REC-html40" xmlns:q="http://schemas.xmlsoap.org/soap/envelope/" xmlns:rtc="http://microsoft.com/officenet/conferencing" xmlns:D="DAV:" xmlns:Repl="http://schemas.microsoft.com/repl/" xmlns:mt="http://schemas.microsoft.com/sharepoint/soap/meetings/" xmlns:x2="http://schemas.microsoft.com/office/excel/2003/xml" xmlns:ppda="http://www.passport.com/NameSpace.xsd" xmlns:ois="http://schemas.microsoft.com/sharepoint/soap/ois/" xmlns:dir="http://schemas.microsoft.com/sharepoint/soap/directory/" xmlns:ds="http://www.w3.org/2000/09/xmldsig#" xmlns:dsp="http://schemas.microsoft.com/sharepoint/dsp" xmlns:udc="http://schemas.microsoft.com/data/udc" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:sub="http://schemas.microsoft.com/sharepoint/soap/2002/1/alerts/" xmlns:ec="http://www.w3.org/2001/04/xmlenc#" xmlns:sp="http://schemas.microsoft.com/sharepoint/" xmlns:sps="http://schemas.microsoft.com/sharepoint/soap/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:udcs="http://schemas.microsoft.com/data/udc/soap" xmlns:udcxf="http://schemas.microsoft.com/data/udc/xmlfile" xmlns:udcp2p="http://schemas.microsoft.com/data/udc/parttopart" xmlns:wf="http://schemas.microsoft.com/sharepoint/soap/workflow/" xmlns:dsss="http://schemas.microsoft.com/office/2006/digsig-setup" xmlns:dssi="http://schemas.microsoft.com/office/2006/digsig" xmlns:mdssi="http://schemas.openxmlformats.org/package/2006/digital-signature" xmlns:mver="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns:mrels="http://schemas.openxmlformats.org/package/2006/relationships" xmlns:spwp="http://microsoft.com/sharepoint/webpartpages" xmlns:ex12t="http://schemas.microsoft.com/exchange/services/2006/types" xmlns:ex12m="http://schemas.microsoft.com/exchange/services/2006/messages" xmlns:pptsl="http://schemas.microsoft.com/sharepoint/soap/SlideLibrary/" xmlns:spsl="http://microsoft.com/webservices/SharePointPortalServer/PublishedLinksService" xmlns:Z="urn:schemas-microsoft-com:" xmlns:st="" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 12 (filtered medium)"><title>Re: [RE-wrenches] AGM battery charging, more details</title><style><!--
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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Hugh, .25 x C20 would be a C80 rate, and with flooded batteries, C100 was the cutoff point at which you could do without a controller. All controllers that I’ve ever worked with make adjustments in current to meet the transitions between bulk-absorption-float. PWM controllers do it by adjusting the width of the current pulse - but by basing the point of transition on reading voltage instead of counting current. I agree that a $450 controller is a lot to add into a small system bid. I’ve generally steered clear of sealed batteries, believing that the trade-off between maintenance and the fragility of plates made with calcium instead of antimony favors adding water occasionally. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Bill Dorsett<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Sunwrights<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Manhattan, KS<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> re-wrenches-bounces@lists.re-wrenches.org [mailto:re-wrenches-bounces@lists.re-wrenches.org] <b>On Behalf Of </b>Hugh<br><b>Sent:</b> Thursday, April 28, 2011 12:59 AM<br><b>To:</b> RE-wrenches<br><b>Subject:</b> Re: [RE-wrenches] AGM battery charging, more details<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>At 22:38 -0500 26/4/11, William Dorsett wrote:<o:p></o:p></p></div><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><p class=MsoNormal><o:p> </o:p></p></blockquote><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><p class=MsoNormal>OK, I can see how you could input the amphr capacity of a given set of new batteries, but would someone explain how a controller which counts amps can adjust as the battery bank ages? As the capacity of the bank drops over time, and this varies by different manufacturers, it still seems that a controller which measures voltage would track the SOC of the bank better than current counting.<o:p></o:p></p></blockquote><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><p class=MsoNormal> <o:p></o:p></p></blockquote><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Keeping track of SOC by counting Ah is a challenge in itself, but the battery manufacturers' instructions don't require this. Fullriver and Surrette require the you make a transition between Absorption and Float charge regimes/stages at a certain point where the charging current drops to a given level (although the Rolls FAQ is puzzling in its wording there - suggesting that you can charge at 0.25 x C20 indefinitely!). Most stand alone RE system controllers do not possess the ability to monitor the battery current, so they cannot follow these instructions. This is my concern. <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><p class=MsoNormal>At 10:54 -0700 26/4/11, Rick Cullen - Blue Sky Energy, Inc. wrote: <o:p></o:p></p><p class=MsoNormal>There has been some discussion in the past few days regarding AGM batteries and charge control switching to Float based on net battery charge current matched to battery size and that our IPN-ProRemote product can provide this.<o:p></o:p></p></blockquote><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Rick's Blue Sky product fits the bill but it seems expensive in the context of very small systems. Phil Smith of Barden Batteries in the UK has told me that a correctly programmed Tristar controller will do a good job even though it does not 'know' the battery current. This is good news.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>I am still deeply puzzled about sealed batteries as I learn that you must not make them gas but you have to be sure to charge them well (like any other lead acid battery) or they will fail prematurely. That's why I would like to be able to fit controllers that monitor the battery current and use this to determine the transition to a float charge. <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Maybe it would help if somebody told me what sort of charging would actually damage a sealed battery. Then I would simply charge them as hard as the wind/sun allows while avoiding doing that.<o:p></o:p></p></div><pre>-- <o:p></o:p></pre><div><p class=MsoNormal>Hugh Piggott<br><br>Scoraig<br>http://www.scoraigwind.co.uk<o:p></o:p></p></div></div></body></html>