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<p class=MsoNormal><span style='font-size:14.0pt;font-family:"Century Gothic","sans-serif"'>For
array to power center or Inverter; I use 125% of amps @ max power and run the
wire calculations at 1% VD.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:14.0pt;font-family:"Century Gothic","sans-serif"'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:14.0pt;font-family:"Century Gothic","sans-serif"'>We
have set Fluke meters on clamped on @ both ends and talked with radios & compared
the readings. We have not seen any noticeable VD down to .00vdc.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:14.0pt;font-family:"Century Gothic","sans-serif"'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:14.0pt;font-family:"Century Gothic","sans-serif"'>Perhaps
overkill?<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:14.0pt;font-family:"Century Gothic","sans-serif"'><o:p> </o:p></span></p>
<div>
<p class=MsoNormal><span style='font-family:"Century Gothic","sans-serif"'>Thanks,
Dana Orzel<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-family:"Century Gothic","sans-serif"'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-family:"Century Gothic","sans-serif"'>Great
Solar Works, Inc<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-family:"Century Gothic","sans-serif"'>E -
dana@solarwork.com<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-family:"Century Gothic","sans-serif"'>V -
970.626.5253<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-family:"Century Gothic","sans-serif"'>F -
970.626.4140<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-family:"Century Gothic","sans-serif"'>C -
970.209.4076<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-family:"Century Gothic","sans-serif"'>web
- www.solarwork.com<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-family:"Century Gothic","sans-serif"'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-family:"Century Gothic","sans-serif"'>"Responsible
Technologies for Responsible People since 1988"</span><span
style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p></o:p></span></p>
</div>
<p class=MsoNormal><span style='font-size:14.0pt;font-family:"Century Gothic","sans-serif"'><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 style='margin-left:.5in'><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>Michael
Kelly<br>
<b>Sent:</b> Thursday, July 22, 2010 2:13 PM<br>
<b>To:</b> 'RE-wrenches'<br>
<b>Subject:</b> Re: [RE-wrenches] calculating DC voltage drop<o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif"'>Hi All,<o:p></o:p></span></p>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif"'><o:p> </o:p></span></p>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif"'>I agree with Ray with the exception that I
use Imp*1.25 in my calculations. I developed a simple spreadsheet for
either fixed conductor size or for fixed voltage drop. You can feel free
to use it by downloading here: <a
href="http://www.mechanicalmike.com/solar/DC_Voltage_Drop_Calculations_Template_04_20_2010.xltx">http://www.mechanicalmike.com/solar/DC_Voltage_Drop_Calculations_Template_04_20_2010.xltx</a>.<o:p></o:p></span></p>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif"'><o:p> </o:p></span></p>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif"'>- Mike<o:p></o:p></span></p>
<div>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif"'>---<o:p></o:p></span></p>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif"'>Michael Kelly<br>
Applications Engineer<o:p></o:p></span></p>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif"'>NABCEP Certified Solar PV Installer ™<o:p></o:p></span></p>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif"'><img border=0 width=150 height=36
id="Picture_x0020_1" src="cid:image001.jpg@01CB29AE.5D958740" alt=toplogo><br>
Solectria Renewables, LLC<o:p></o:p></span></p>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif"'>360 Merrimack St.<o:p></o:p></span></p>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif"'>Building 9, Floor 2<o:p></o:p></span></p>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif"'>Lawrence, MA 01843<br>
Phone: 978-683-9700 ext. 167<br>
Fax: 978-683-9702<o:p></o:p></span></p>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif"'><a href="mailto:mike@solren.com">mike@solren.com</a><o:p></o:p></span></p>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif"'><a href="http://www.solren.com/">www.solren.com</a><o:p></o:p></span></p>
</div>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif"'><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 style='margin-left:.5in'><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>R Ray
Walters<br>
<b>Sent:</b> Thursday, July 22, 2010 3:45 PM<br>
<b>To:</b> RE-wrenches<br>
<b>Subject:</b> Re: [RE-wrenches] calculating DC voltage drop<o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p>
<p class=MsoNormal style='margin-left:.5in'>I use actual operating current,
without multipliers. I also use actual temperatures, not the worst case
temperatures that many use.<o:p></o:p></p>
<div>
<p class=MsoNormal style='margin-left:.5in'>I created a spread sheet that uses
the NEC adjustments for wire temperature, (see NEC chapter 9, table 8, FPN 2)<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal style='margin-left:.5in'>It makes quite a difference!<o:p></o:p></p>
<div>
<p class=MsoNormal style='margin-left:.5in'>Volt drop and the accompanying loss
of energy production needs to be looked at realistically under normal operating
conditions. Adding worst case multipliers is necessary for sizing cables and
breakers for safety, but it isn't appropriate when calculating energy losses.
We shouldn't do an energy loss analysis for a situation that might never occur,
or for only a very small % of the time. <o:p></o:p></p>
</div>
<div>
<p class=MsoNormal style='margin-left:.5in'>A correct analysis will reflect
actual losses over the lifetime of the system, so that an informed economic
decision can be made. Especially on larger systems with long runs, its worth it
to you and the client to use real world numbers, not blind over sizing.<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal style='margin-left:.5in'>I got into this over a decade ago,
when I noticed that actual measured volt drop was much less than calculated,
now my calculations match real measurements. <o:p></o:p></p>
</div>
<div>
<p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p>
<div>
<div>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:9.0pt;
font-family:"Helvetica","sans-serif";color:black'>R. Walters<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:9.0pt;
font-family:"Helvetica","sans-serif";color:black'><a
href="mailto:ray@solarray.com">ray@solarray.com</a><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:9.0pt;
font-family:"Helvetica","sans-serif";color:black'>Solar Engineer<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:9.0pt;
font-family:"Helvetica","sans-serif";color:black'><o:p> </o:p></span></p>
</div>
<div>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:9.0pt;
font-family:"Helvetica","sans-serif";color:black'><o:p> </o:p></span></p>
</div>
<p class=MsoNormal style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:
12.0pt;margin-left:.5in'><o:p> </o:p></p>
</div>
<p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p>
<div>
<div>
<p class=MsoNormal style='margin-left:.5in'>On Jul 22, 2010, at 1:22 PM, Marco
Mangelsdorf wrote:<o:p></o:p></p>
</div>
<p class=MsoNormal style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:
12.0pt;margin-left:.5in'><o:p> </o:p></p>
<div>
<div>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif"'>When calculating the voltage drop from a PV
array to the inverter, what’s the most common accepted practice? To
use the Isc X 1.25 or 1.56 as the multiplier?<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif"'> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif"'>Thanks,<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif"'>marco<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif"'> <o:p></o:p></span></p>
</div>
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