<html><body><span style="font-family:Verdana; color:#000000; font-size:10pt;"><div>Check out Tigo Optimizers:</div><div><br></div><div> <a href="http://www.tigoenergy.com">http://www.tigoenergy.com</a>/ <br></div><div><br></div><div>db<br>Dan Brown<br>Foxfire Energy Corp.<br>Renewable Energy Systems<br>(802)-483-2564<br><a href="http://www.Foxfire-Energy.com">www.Foxfire-Energy.com</a><br>NABCEP #092907-44</div><div><br><br></div>
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-------- Original Message --------<br>
Subject: Re: [RE-wrenches] Fwd: Charge control question<br>
From: Jeff Irish <<a href="mailto:jeff@hudsonsolar.com">jeff@hudsonsolar.com</a>><br>
Date: Thu, October 11, 2012 2:58 pm<br>
To: "<a href="mailto:Allan@positiveenergysolar.com">Allan@positiveenergysolar.com</a>" <<a href="mailto:Allan@positiveenergysolar.com">Allan@positiveenergysolar.com</a>>,<br>
RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org">re-wrenches@lists.re-wrenches.org</a>><br>
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</style> <div class="WordSection1"> <div class="MsoNormal" style="font-size:12pt;"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">Blue Sky has 15 and 30 amp, 12 and 24 volt charge controllers that are each independently MPPT that can be networked to their controller to communicate and charge a single large battery bank. <o:p></o:p></span></div> <div class="MsoNormal" style="font-size:12pt;"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">Jeff Irish<o:p></o:p></span></div> <div class="MsoNormal" style="font-size:12pt;"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">Hudson Solar<o:p></o:p></span></div> <div class="MsoNormal" style="font-size:12pt;"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D"><o:p> </o:p></span></div> <div> <div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in"> <div class="MsoNormal" style="font-size:12pt;"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext"> <a href="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a> [<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org">mailto:re-wrenches-bounces@lists.re-wrenches.org</a>] <b>On Behalf Of </b>Allan Sindelar<br> <b>Sent:</b> Thursday, October 11, 2012 1:04 PM<br> <b>To:</b> RE-wrenches<br> <b>Subject:</b> [RE-wrenches] Fwd: Charge control question<o:p></o:p></span></div> </div> </div> <div class="MsoNormal" style="font-size:12pt;"><o:p> </o:p></div> <div class="MsoNormal" style="font-size:12pt;">Wrenches,<br> I'm posting this for Carl Bickford, prof emeritus of the renewable energy training program at San Juan College in Farmington, New Mexico. I'll forward your responses to him.<o:p></o:p></div> <div> <div> <blockquote style="margin-top:5.0pt;margin-bottom:5.0pt"> <div class="MsoNormal" style="font-size:12pt;mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">I have a very interesting and talented friend who is rebuilding a blue-water sailboat for a round-the-world trip. He is well versed in solar and is trying to use a relatively large array to charge a big battery bank that will be used for propulsion as well as general electrical. The propulsion system will be backed up with a propane generator he is building himself out of a Toyota truck engine.<o:p></o:p></div> <div class="MsoNormal" style="font-size:12pt;mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">As you can imagine, there is no place on a sailboat where shading isn’t a problem. He and I were wondering if there were products out there that could MPPT either individual modules, or small groups of them for 12 V battery charging. I have seen such things for the inputs of grid-tied inverters, but nothing yet for off-grid. The other choice is to go with many small MPPT charge controllers like the ones from Solar Converters.<o:p></o:p></div> <div class="MsoNormal" style="font-size:12pt;mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Any advice you can offer?<o:p></o:p></div> <div class="MsoNormal" style="font-size:12pt;mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Take care,<br> Carl <br> <br> <o:p></o:p></div> </blockquote> <div class="MsoNormal" style="font-size:12pt;mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Carl Bickford<br> Professor of Engineering and Renewable Energy<br> San Juan College<br> 4601 College Blvd.<br> Farmington, NM 87402<br> 505-566-3503<br> <a target="_blank" href="mailto:bickfordc@sanjuancollege.edu">bickfordc@sanjuancollege.edu</a><o:p></o:p></div> <div class="MsoNormal" style="font-size:12pt;mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <br> I offered the suggestion below. Certainly open to other and better ideas.<br> Allan<br> <br> <o:p></o:p></div> <blockquote style="margin-top:5.0pt;margin-bottom:5.0pt"> <div class="MsoNormal" style="font-size:12pt;mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">I have not encountered this situation, so I have no advice from experience. At 12V, it's hardly an issue as it is with high voltage parallel strings, where a few shaded cells can cause a whole string to drop out of the inverter's MPPT. At most, a shaded cell weakens the output of that module. And since it's charging batteries, there's a greater amount of head room.<br> <br> I would suggest looking into Blue Sky Energy's "i" series - smaller MPPT controllers that can be networked. We seldom use them, as our residential applications are different. But you could put a controller on a group of modules and network several together. One advantage, I think (you'd want to check this) is that Blue Sky's MPPT algorithm is analog, unlike Outback and others: on the old Solar Boost series, the MPPT boost was set with a trim pot to a particular voltage above battery voltage; the target is to set it to where the boost was greatest. You could set this boost slightly lower than peak, and output just a little below MPP. That way the overall output would be minimally reduced, and a modest amount of shading would not cause the shaded module to drop below collective MPP as readily.<o:p></o:p></div> </blockquote> <div class="MsoNormal" style="font-size:12pt;"><br> <b>Allan Sindelar</b><br> <span style="font-size:10.0pt"><a target="_blank" href="mailto:Allan@positiveenergysolar.com"><span style="color:#000099">Allan@positiveenergysolar.com</span></a></span><br> <span style="font-size:10.0pt">NABCEP Certified Photovoltaic Installer<br> NABCEP Certified Technical Sales Professional<br> New Mexico EE98J Journeyman Electrician<br> Founder and Chief Technology Officer<br> <b>Positive Energy, Inc.</b><br> 3209 Richards Lane (note new address)<br> Santa Fe, New Mexico 87507<br> <b>505 424-1112</b><br> <a href="http://www.positiveenergysolar.com/" target="_blank">www.positiveenergysolar.com</a></span> <o:p></o:p></div> <div class="MsoNormal" style="font-size:12pt;mso-margin-top-alt:auto;margin-right:722.25pt;mso-margin-bottom-alt:auto"> <o:p> </o:p></div> </div> <div class="MsoNormal" style="font-size:12pt;margin-bottom:12.0pt"><o:p> </o:p></div> </div> <div class="MsoNormal" style="font-size:12pt;"><br> <br> -- <br> This message has been scanned for viruses and <br> dangerous content by <a target="_blank" href="http://www.hvcomputerservices.com/"><b>Hudson Valley Computer Services</b></a>, and is <br> believed to be clean. <o:p></o:p></div> </div> <hr>_______________________________________________<br>
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