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    Actually its much more cost effective to use charge controllers than
    GT inverters for the PV input.   Just price out a 4 Kw GT inverter
    of your choice compared to a Midnite Classic for instance.  It's in
    the ball park of 25 cents/ watt savings, and that's not chump
    change.<br>
    I only use AC coupling when the GT system is already in place, and
    we're adding battery backup.<br>
    <pre class="moz-signature" cols="72">R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer, 
Licensed Master Electrician
Solar Design Engineer
303 505-8760</pre>
    <div class="moz-cite-prefix">On 6/6/2015 8:49 AM, Jeff Clearwater
      wrote:<br>
    </div>
    <blockquote
      cite="mid:F743DEF3-F58F-4638-9D56-BFE990CA426C@villagepowerdesign.com"
      type="cite">
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      <div>Hi Mark</div>
        Seems a shame to spend the money on a charge control etc when
      SMA has carefully provided a built in solution. 
      <div><br>
      </div>
      <div>If you do decide to go that route you'll need to install a
        Shunt and set up the DC Current Sense circuit so the inverter
        knows what other current is flowing to and fro the batteries. </div>
      <div><br>
      </div>
      <div>Best,</div>
      <div><br>
      </div>
      <div>Jeff</div>
      <div><br>
      </div>
      <div><br>
      </div>
      <div><br>
      </div>
      <div><br>
        <br>
        Sent from my iPhone</div>
      <div><br>
        On Jun 6, 2015, at 7:23 AM, Mac Lewis <<a
          moz-do-not-send="true" href="mailto:maclewis1@gmail.com">maclewis1@gmail.com</a>>
        wrote:<br>
        <br>
      </div>
      <blockquote type="cite">
        <div>
          <div dir="ltr">Hi Mark,
            <div><br>
            </div>
            <div>The Sunny Island has various battery protection modes
              and will shutdown based on user programmable state of
              charge levels. Level 2 battery protection will start the
              Sunny Island every 2 hours in an attempt to get charge
              into the batteries.  You should set this level up at times
              when energy input is likely.  See page 113-114 here: <a
                moz-do-not-send="true"
                href="http://files.sma.de/dl/15216/SI4548-6048-US-BE-en-20.pdf">http://files.sma.de/dl/15216/SI4548-6048-US-BE-en-20.pdf</a>
               If it doesn't get any charging to the batteries for 10
              minutes, it will shut down and wait again.</div>
            <div><br>
            </div>
            <div>This is an advantage of having at least some DC coupled
              solar input.</div>
            <div><br>
            </div>
            <div><br>
            </div>
          </div>
          <div class="gmail_extra"><br>
            <div class="gmail_quote">On Sat, Jun 6, 2015 at 7:39 AM,
              Mark Frye <span dir="ltr"><<a moz-do-not-send="true"
                  href="mailto:markf@berkeleysolar.com" target="_blank">markf@berkeleysolar.com</a>></span>
              wrote:<br>
              <blockquote class="gmail_quote" style="margin:0 0 0
                .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi
                Guys,<br>
                <br>
                Just wondering about how a SI/SB microgrid works. If all
                the PV is connected to SB inverters, what happens if the
                loads manage to drain the batteries to their low voltage
                shutdown? Wouldn't the SB stop providing the AC sync so
                then the SB wouldn't have anything to sync to even if
                they had power available from the PV?<br>
                <br>
                How is this handled? It seems to me you would always
                want to have some amount of PV DC coupled.<br>
                <br>
                Thanks,<br>
                <br>
                Mark Frye<br>
                Berkeley Solar Electric Systems<br>
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            <div><br>
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            -- <br>
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              <div><font color="#305A78" face="'times new roman', serif"><br>
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              Mac Lewis<br>
              <br>
              <span style="font-family:'Times New
                Roman';font-size:medium;color:rgb(255,153,0)"><b><font
                    face="Arial, Helvetica, sans-serif" size="3">
                    <p align="left"><font color="#000000" face="Verdana,
                        Arial, Helvetica, sans-serif"><span
                          style="font-size:small"><span
                            style="font-family:arial;font-weight:normal;color:rgb(48,90,120)"><font
                              face="'times new roman', serif">"Yo solo
                              sé que no sé nada." </font><span
                              style="font-weight:700;color:rgb(104,104,104)"><font
                                face="'times new roman', serif">-Sócrates</font></span></span></span></font></p>
                  </font></b></span></div>
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      <blockquote type="cite">
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