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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:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'>To All,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'> Great insight on the lithium movement. I do am looking for anyone dealing with the new Aquion batteries. I’ve got a couple of potential clients that have inquired about them. Saw them at a NABCEP training session last spring and while the idea is moving I wasn’t impressed. Perhaps it’s time to start a new thread, “Aquion batteries”.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Thanks,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Christopher<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","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 [mailto:re-wrenches-bounces@lists.re-wrenches.org] <b>On Behalf Of </b>don@energysolarnow.com<br><b>Sent:</b> Friday, 29 January, 2016 00:49<br><b>To:</b> Dan Fink<br><b>Cc:</b> re-wrenches@lists.re-wrenches.org<br><b>Subject:</b> Re: [RE-wrenches] LiFePO4; WAS Availability of Powerwall Batteries<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";color:black'>Thanks for sharing your experience with these batteries, Dan.<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";color:black'>I have similar SOC issues with an off-grid customer who has the Aquion Hybrid Ion batteries.<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";color:black'>It has difficulty reaching full charge from solar, requiring the genny to kick on each morning even in the summer.<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";color:black'>This is even worse in cold winter weather.<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";color:black'>Your explanation of the change in Peukert's exponent above 80% SOC with NiFe batteries sounds like what is happening here as well. <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";color:black'>Do you have any experience with Aquion batteries that you can share?<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";color:black'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";color:black'>Thanks<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";color:black'>Don Barch <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";color:black'>Energy Solar<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";color:black'><a href="mailto:don@energysolarnow.com">don@energysolarnow.com</a><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";color:black'><o:p> </o:p></span></p></div><blockquote style='border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in 6.0pt;margin-left:6.0pt;margin-top:5.0pt;margin-bottom:5.0pt' id=replyBlockquote><div id=wmQuoteWrapper><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";color:black'>Message: 2<br>Date: Mon, 25 Jan 2016 15:51:26 -0700<br>From: Dan Fink <<a href="mailto:danbob88@gmail.com">danbob88@gmail.com</a>><br>To: RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org">re-wrenches@lists.re-wrenches.org</a>><br>Subject: Re: [RE-wrenches] LiFePO4; WAS Availability of Powerwall<br>Batteries<br>Message-ID:<br><<a href="mailto:CAF+3LndeD2av3Ji9CPRZi1mrw04ohFCk2UgMtu=RoWLPr3REKw@mail.gmail.com">CAF+3LndeD2av3Ji9CPRZi1mrw04ohFCk2UgMtu=RoWLPr3REKw@mail.gmail.com</a>><br>Content-Type: text/plain; charset="utf-8"<br><br>Hello Mark;<br>My NiFes went in last March, I'm almost at a year living with them off the<br>grid.<br>To avoid writing a novel here I'll group my comments into Oddities,<br>Advantages and Disadvantages.<br><br>Advantages:<br>~ at least 25 year lifespan<br>~ 10 year warranty<br>~ Can add more parallel strings at any time/age, just drain and replace<br>electrolyte of old batteries<br>~ 80% depth of discharge no problem, so can size smaller amp-hour capacity<br><br>Oddities:<br>~ alkaline electrolyte, neutralize spills and clean tops with white vinegar<br>~ Specific gravity of electrolyte does not change with state of charge so a<br>hydrometer is useless<br>~ Charge / discharge efficiency changes greatly with state of charge.<br>Sometimes my Magnum ME-BMK amp hour meter matches the Midnite Whizbang Jr<br>exactly, sometimes they are way off from each other. For ground truth, the<br>state of charge vs. voltage curve from the battery manufacturer seems right<br>on, not counting false readings when the batteries are not at rest for a<br>couple hours.<br>~ Fooling PV MPPT charge controllers into dealing with NiFes involves<br>setting a very long and high Absorb voltage<br>~ Charge efficiency is great up to 80% state of charge, but after that<br>drops way off. Above 80% SOC these batteries want to see 1.65v per cell to<br>really fill up. No problem for modern MPPT PV controllers, but-<br>~ Some inverter / chargers (Magnum here) freak out and shut down at 1.6v<br>per cell, so the solution from the battery manufacturer is-<br>~ Run fewer cells during times of year when charging is frequent from the<br>generator, put the extra cells back in the string during times of year when<br>the charging is mostly PV. Sitting uncharged does not damage these "extra"<br>cells.<br>~ So I am running a 10.8v battery bank right now, will bring it back to 12v<br>this spring. No big deal, but does affect inverter surge capacity. Would<br>not be as much of a problem at 24v or 48v.<br>~<br><br>Disadvantages:<br>~ The high Absorb voltage to get that last 20% SOC efficiently bubbles<br>through a lot of distilled water. My schedule is 1-2 gallons every 40 days,<br>and the company sends a reminder email at that interval.<br>~ The bubbling gets the tops dirty fast. A cleaning every 40 days is about<br>right.<br>~ High cost<br>~ Twiddling with string voltages semi-annually. This would not be an issue<br>if most charging is from PV.<br><br>My thoughts:<br>My overall impression of being married to NiFes way off the grid has so far<br>been <a href="http://favorable.In">favorable.In</a> a grid standby situation, I think string voltage<br>twiddling would be a non-issue, who cares about the last 20% of SOC charge<br>efficiency in that situation? Off the grid with daily cycling, generator<br>use, etc, I would not consider these to be batteries for off-grid<br>beginners. But anyone who has been off grid for a few years with lead acid<br>batteries will immediately appreciate the advantages and only occasionally<br>curse the quirks of Nife.<br>Plans here: Increase my PV by about 30%. Cheap and easy, no more taking<br>cells in and out of the string, and less winter generator run time. Get 'em<br>to 80% on genny during tough snowbound times and let PV do the rest. Figure<br>out some Arduino solution for monitoring when Peukert's exponent changes<br>depending on SOC. Complain to inverter/charger manufacturers to make them<br>work better with NiFe.<br><br>Best regards;<br><br>Dan Fink<br>Adjunct Professor, Ecotech Institute<br>IREC Certified Instructor? for:<br>~ PV Installation Professional<br>~ Small Wind Installer<br>Executive Director, Buckville Energy<br>NABCEP Accredited Continuing Education Providers?<br>970.672.4342<br><br><br><br><o:p></o:p></span></p></div></blockquote></div></body></html>