<HTML xmlns="http://www.w3.org/TR/REC-html40" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:v="urn:schemas-microsoft-com:vml" xmlns:w="urn:schemas-microsoft-com:office:word"><head><META content="text/html; charset=us-ascii" http-equiv="Content-Type">
<meta content="text/html; charset=us-ascii" http-equiv=Content-Type><meta content="Microsoft Word 14 (filtered medium)" name=Generator><!--[if !mso]><style>v\:* {behavior:url(#default#VML);}
o\:* {behavior:url(#default#VML);}
w\:* {behavior:url(#default#VML);}
.shape {behavior:url(#default#VML);}
</style><![endif]--><style><!--
/* Font Definitions */
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
@font-face
{font-family:Verdana;
panose-1:2 11 6 4 3 5 4 4 2 4;}
@font-face
{font-family:Consolas;
panose-1:2 11 6 9 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";
color:black;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
p.MsoAutoSig, li.MsoAutoSig, div.MsoAutoSig
{mso-style-priority:99;
mso-style-link:"E-mail Signature Char";
margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
pre
{mso-style-priority:99;
mso-style-link:"HTML Preformatted Char";
margin:0in;
margin-bottom:.0001pt;
font-size:10.0pt;
font-family:"Courier New";
color:black;}
p.MsoAcetate, li.MsoAcetate, div.MsoAcetate
{mso-style-priority:99;
mso-style-link:"Balloon Text Char";
margin:0in;
margin-bottom:.0001pt;
font-size:8.0pt;
font-family:"Tahoma","sans-serif";
color:black;}
span.HTMLPreformattedChar
{mso-style-name:"HTML Preformatted Char";
mso-style-priority:99;
mso-style-link:"HTML Preformatted";
font-family:"Consolas","serif";
color:black;}
span.E-mailSignatureChar
{mso-style-name:"E-mail Signature Char";
mso-style-priority:99;
mso-style-link:"E-mail Signature";
font-family:"Calibri","sans-serif";
color:black;}
span.EmailStyle21
{mso-style-type:personal;
font-family:"Arial","sans-serif";
color:navy;}
span.EmailStyle22
{mso-style-type:personal-reply;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.BalloonTextChar
{mso-style-name:"Balloon Text Char";
mso-style-priority:99;
mso-style-link:"Balloon Text";
font-family:"Tahoma","sans-serif";
color:black;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.25in 1.0in 1.25in;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]--></head><BODY>
<DIV><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>This all works fine, until you fire up a generator to charge batteries. If the generator remains within voltage and frequency limits, you stand a good chance of overvoltaging the batteries. In this situation it is best to disable the utility-interactive PV system while charging batteries from the generator.<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'>The SMA system gets around this limitation by using RS485 communication between the SI and the SunnyBoys. When set to off-grid mode, the Sunnyboys will limit their output power limit from 100% to 0% based on commands from the SI, so battery voltage can be limited, even when charging from the generator. <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><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1F497D'>See ya!<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1F497D'>Marv<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Director of Technology and Support, North America<o:p></o:p></span></p><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>SolarEdge Technologies, Inc.<o:p></o:p></span></b></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Tech Support North America: +877.360.5292<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Mobile: +530.392.0356<o:p></o:p></span></p></div><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";color:windowtext'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'> re-wrenches-bounces@lists.re-wrenches.org [mailto:re-wrenches-bounces@lists.re-wrenches.org] <b>On Behalf Of </b>Brian Faley<br><b>Sent:</b> Friday, September 02, 2011 5:21 PM<br><b>To:</b> Allan@positiveenergysolar.com; RE-wrenches<br><b>Subject:</b> Re: [RE-wrenches] AC Coupling<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:navy'>Hi Allen,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:navy'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:navy'>I’ll try to describe the typical AC coupled system as well as I can.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:navy'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:navy'>In such a system, a NON-grid tied battery based inverter (i.e. Magnum MS PAE) is connected as a backup inverter, only supplying AC power to consumer’s loads when the grid is down. The micro inverter(s), or string inverters are connected on the load side of the inverters transfer switch, in parallel with the inverter output so they see AC grid power (when available) or inverter power when the grid goes down. The micro inverters / string inverters in such a system are called AC coupled inverters because the point of coupling is the AC system rather than the DC system. This allows the battery based inverter to provide the grid reference to the AC coupled grid-tied inverters when the utility power is not present – Backup mode. In that mode the inverter will form the reference for the grid tied inverters and any surplus power supplied by the grid-tied inverters that is not being consumed by AC loads will charge the battery of the inverter. In this inverter mode, once the battery is full, the inverter senses it and shifts the inverter frequency by .5hz to force the grid tied inverters off, keeping them from exporting power, thereby stopping the battery from overcharging. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:navy'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:navy'>On a large system, a DC diversion load is usually added in parallel with the battery to reduce the on/off cycling of the grid tied inverters, which once the frequency shift happens, will try to reconnect every five minutes without it. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:navy'>Using the frequency shift method only is rather crude, because it essentially is a bang/bang controller – off or on. Its not a matter of our lack of confidence in the approach, the question is do you want the battery voltage swinging around by several volts. In a DC diversion mode system, the surplus energy from the grid tied inverters can be put to work as a useful dump load rather than just off lining several kw of PV. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:navy'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:navy'>We had a white paper describing the AC couple mode. I’ll see what we can do to make it more widely available, since the interest in such systems seems to be increasing.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:navy'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:navy'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:navy'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:navy'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:navy'><o:p> </o:p></span></p><div><p class=MsoAutoSig><span style='color:navy'>Brian Faley<o:p></o:p></span></p><p class=MsoAutoSig><span style='color:navy'>Chief Engineer<o:p></o:p></span></p><p class=MsoAutoSig><span style='color:navy'>Magnum Energy<o:p></o:p></span></p><p class=MsoAutoSig><span style='color:navy'>2111 W Casino Rd<o:p></o:p></span></p><p class=MsoAutoSig><span style='color:navy'>Everett, WA 98204<o:p></o:p></span></p><p class=MsoAutoSig><span style='color:navy'>425-353-8833<o:p></o:p></span></p><p class=MsoAutoSig><span style='color:navy'><a href="mailto:bfaley@magnumenergy.com">bfaley@magnumenergy.com</a><o:p></o:p></span></p></div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:navy'><o:p> </o:p></span></p><div style='border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in 4.0pt'><div><div align=center class=MsoNormal style='text-align:center'><span style='color:windowtext'><hr align=center size=2 width="100%"></span></div><p class=MsoNormal><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'> re-wrenches-bounces@lists.re-wrenches.org [mailto:re-wrenches-bounces@lists.re-wrenches.org] <b>On Behalf Of </b>Allan Sindelar<br><b>Sent:</b> Friday, September 02, 2011 4:45 PM<br><b>To:</b> RE-wrenches<br><b>Subject:</b> Re: [RE-wrenches] AC Coupling</span><span style='color:windowtext'><o:p></o:p></span></p></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Brian,<br>Could you speak a bit more to this, please? My understanding is that the need with a string (or, I suppose, micro-) inverter and a battery-based inverter is for a way to disconnect full batteries from being overcharged when the grid is down and sell is disabled. The SMA approach is to shift frequency to reduce string inverter output. I thought that the battery-based (Outback, Magnum) approach is to use a contactor to open string inverter AC based on voltage (crude, but effective). <br><br>So what I understand is that the PAE inverters shift frequency: do you mean it simulates the shift that a Sunny Island would do? And if so, why is a diversion load recommended, and how is it configured into the system? And where can we read more about how this is designed to work?<br>Thank you,<br>Allan<br> <o:p></o:p></p><div><p class=MsoNormal><b>Allan Sindelar</b><br><span style='font-size:10.0pt'><a 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><b>Positive Energy, Inc.</b><br>3201 Calle Marie<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></p></div><p class=MsoNormal><br>On 9/2/2011 4:39 PM, Brian Faley wrote: <o:p></o:p></p><pre>Hi Larry, <o:p></o:p></pre><pre>Magnum MS PAE inverters do indeed shift the inverter output frequency<o:p></o:p></pre><pre>when the battery is full in order to disconnect grid-tied inverters used<o:p></o:p></pre><pre>in AC coupled systems. It was designed to work in conjunction with a DC<o:p></o:p></pre><pre>diversion load - which is recommended if the system is larger than a<o:p></o:p></pre><pre>couple panels.<o:p></o:p></pre><pre><o:p> </o:p></pre><pre>Regards,<o:p></o:p></pre><pre><o:p> </o:p></pre><pre>Brian Faley<o:p></o:p></pre><pre>Chief Engineer<o:p></o:p></pre><pre>Magnum Energy<o:p></o:p></pre><pre>2111 W Casino Rd<o:p></o:p></pre><pre>Everett, WA 98204<o:p></o:p></pre><pre>425-353-8833<o:p></o:p></pre><pre><a href="mailto:bfaley@magnumenergy.com">bfaley@magnumenergy.com</a><o:p></o:p></pre></div><p class=MsoNormal style='margin-bottom:12.0pt'><span style='color:windowtext'><br><br><br><br>************************************************************************************<br>This footnote confirms that this email message has been scanned by<br>PineApp Mail-SeCure for the presence of malicious code, vandals & computer viruses.<br>************************************************************************************<o:p></o:p></span></p></div></DIV>
<DIV STYLE="FONT-FAMILY: Courier New; FONT-SIZE: 9pt">
<P CLASS="MsoNormal" STYLE="MARGIN: 0cm 0cm 0pt"><FONT FACE="Calibri"><SPAN STYLE="COLOR: navy; FONT-SIZE: 10pt">CONFIDENTIALITY NOTICE: This e-mail and its attachments are intended only for the use of the individual or entity who is the intended recipient and may contain information that is privileged, confidential and exempt from disclosure or any type of use under applicable law. If the reader of this e-mail is not the intended recipient, or the employee, agent, or representative responsible for delivering the e-mail to the intended recipient, you are hereby notified that any dissemination, distribution, copying, or other use of this e-mail is strictly prohibited. If you have received this e-mail in error, please reply immediately to the sender.</SPAN></FONT> </P><FONT FACE="Calibri"><SPAN STYLE="COLOR: navy; FONT-SIZE: 10pt">
<P CLASS="MsoNormal" STYLE="MARGIN: 0cm 0cm 0pt"><B><SPAN LANG="DE" STYLE="FONT-FAMILY: Webdings; COLOR: green; FONT-SIZE: 13.5pt; mso-ansi-language: DE">P</SPAN></B><SPAN STYLE="COLOR: green; FONT-SIZE: 10pt"> Please think of the environment before printing this email</SPAN><SPAN STYLE="COLOR: #4f81bd"></SPAN></P></SPAN></FONT></DIV></BODY></HTML>