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</o:shapelayout></xml><![endif]--></head><body lang=EN-NZ link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Cambria","serif";color:black'>That is why for years we have been twisting those leads around each other. I was told it was to cancel out the opposing fields on the wires, but for whatever the correct technical reason is, we have always twisted those heavy wires. John V.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Cambria","serif";color:black'><o:p> </o:p></span></p><p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span lang=EN-US 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>Jarmo.Venalainen@schneider-electric.com<br><b>Sent:</b> Saturday, 27 June 2015 5:45 a.m.<br><b>To:</b> RE-wrenches<br><b>Subject:</b> [RE-wrenches] Battery Bank to Inverter Wiring<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Hi:</span> <br><br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>From time to time over the years I've come across systems where the routing of DC cables between the batteries and the inverter has been the cause of issues.</span> <br><br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>I'm not referring to wire thickness or quality of terminations. For the purposes of this discussion, just assume that wire thickness and terminations are perfect.</span> <br><br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>What I am referring to is the routing of the positive and negative battery cables. In particular, the loop area within the + and - cables as shown in the image below,</span> <br><br><img width=465 height=313 id="_x0000_i1025" src="cid:image001.gif@01D0B119.912F4F80"><br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>The problem I've seen in systems with a large loop in the setup is that the inverter does not provide good surge power and can even go into low voltage shutdown during large surges.</span> <br><br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Recently this happened again and I wanted to get a better feel for it, so I did some math. </span> <br><br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>For a cable length of about 12', the loop is an inductor which has a value of inductance of about 1 uH for side by side cables and as much as 6 uH for cables about 1 foot apart. </span> <br><br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>This inductance is greatly multiplied by any ferrous metal in the loop and can easily be in the range of 10's to 100's of uH. Examples being cables which run in steel conduits or along the steel frame of a motor home.</span> <br><br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Inductance causes a voltage drop proportional to the rate at which the current is changing. To get an idea of how large that rate can be for typical inverters, I did surge tests with a 5kW inverter and found that the rate of change of current can be as high as 100A per milli-second or 100,000 Amps/second.</span> <br><br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Given that, the voltage drop of the wire inductance is then , Vdrop = (rate of change of current) x (inductance), </span><br><br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Vdrop for 1 uH = (100,000 A/s) x (0.000001 H) = 0.1V</span> <br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Vdrop for 10 uH = (100,000 A/s) x (0.000001 H) = 1.0V</span> <br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Vdrop for 100 uH = (100,000 A/s) x (0.000001 H) = 10.0V clearly this is a problem.</span> <br><br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Have any of the wrenches had systems with this issue? If so, how often.</span> <br><br><br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>JARMO</span> <br><br><br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> <br></span><span style='color:green'>_____________________________________________________________________________________</span> <br><b><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'><br>Jarmo Venalainen</span></b><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'> | <b><span style='color:green'> Schneider Electric </span> | Xantrex Brand</b> | <b>CANADA</b> | <b>Sales Application Engineer</b> <b><br>Phone:</b> +604-422-2528 | <b>Tech Support:</b> 800-670-0707 | <b>Mobile:</b> +604-505-0291 <b><br>Email:</b> </span><a href="mailto:jarmo.venalainen@schneider-electric.com"><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'>jarmo.venalainen@schneider-electric.com</span></a><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'> | <b>Site:</b></span><a href="http://www.xantrex.com/" target="_blank"><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'> www.Xantrex.com</span></a><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'> | <b>Address:</b> 3700 Gilmore Way, Burnaby, BC V5G4M1 </span><o:p></o:p></p><table class=MsoNormalTable border=0 cellpadding=0><tr><td colspan=4 style='padding:.75pt .75pt .75pt .75pt'><p class=MsoNormal><a href="http://www.xantrexrebate.com/" target="_blank"><span style='text-decoration:none'><img border=0 width=1 height=1 id="_x0000_i1026" src="cid:image002.png@01D0B119.912F4F80"></span></a><o:p></o:p></p></td></tr><tr><td style='padding:.75pt .75pt .75pt .75pt'><p class=MsoNormal><a href="http://www.xantrex.com/" target="_blank"><span style='text-decoration:none'><img border=0 width=166 height=55 id="_x0000_i1027" src="cid:image003.gif@01D0B119.912F4F80"></span></a><o:p></o:p></p></td><td style='padding:.75pt .75pt .75pt .75pt'><p class=MsoNormal><a href="https://www.facebook.com/Xantrex" target="_blank"><span style='text-decoration:none'><img border=0 width=36 height=55 id="_x0000_i1028" src="cid:image004.gif@01D0B119.912F4F80"></span></a><o:p></o:p></p></td><td style='padding:.75pt .75pt .75pt .75pt'><p class=MsoNormal><a href="https://twitter.com/Xantrex" target="_blank"><span style='text-decoration:none'><img border=0 width=38 height=55 id="_x0000_i1029" src="cid:image005.gif@01D0B119.912F4F80"></span></a><o:p></o:p></p></td><td style='padding:.75pt .75pt .75pt .75pt'><p class=MsoNormal><a href="https://twitter.com/Xantrex" target="_blank"><span style='text-decoration:none'><img border=0 width=303 height=55 id="_x0000_i1030" src="cid:image006.gif@01D0B119.912F4F80"></span></a><o:p></o:p></p></td></tr></table><p class=MsoNormal><br><br><span style='font-size:7.5pt;font-family:"Arial","sans-serif";color:#00A000'><br>*** Please consider the environment before printing this e-mail</span><o:p></o:p></p></div></body></html>