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<DIV><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Alan:<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'>In my experience, the worst case currents occur during battery charging following a deep discharge.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>(You should see a generator exhaust pipe at night when charging hard – such a pretty shade of yellow/orange)<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 SI has parameters you can set to limit the maximum charge rates which should solve your concern.<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'>This is found in SI Parameter #222.01 under the Battery Settings menu<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>#222 Battery Charge Mode<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>No. __Name Description__Value Explanation ___Default value<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>01__ BatChrgCurMax__Charging current of the battery10 A … 1200 A__1,200 A<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I am not sure if this value is the sum of the SI currents or if this is actually the value the inverters read off the external current shunt needed for DC coupled systems.<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I think the SI uses the current shunt value (if present) but I am not sure - Check with SMA Support to find out. <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>If it is the former then you would need to consider the Radian charge current and subtract that off your maximum allowed value then enter that “net” value into the SI’s.<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'>As I mentioned in my earlier posts the breaker in the SI was selected to match the short duration current versus time trip curves.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Since the SI can do very substantial surges (up to 12 kVA per inverter) the short duration tripping characteristics were key. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>As I recall the breaker was actually 2 internally parallel AMS 125 (non-standard part from Eaton).<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>See curve 252 (DC 25x) data on page 8 of the following <a href="http://www.heinemann-electric.com/acrobat/ams-cata.pdf">http://www.heinemann-electric.com/acrobat/ams-cata.pdf</a><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Not sure what breaker is used in current SI production but the characteristics should be similar to the above.<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'>In normal operation the maximum continuous current will be the inverter rating divided by minimum battery voltage.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I ASS U ME this is where the 125 Amp recommendation for a SI5000 comes from (5000W/40Vdc).<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Never mind that pesky 1.25 * the continuous current NEC thingy.<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'>If you are using an external OCPD be sure to use a L…O…N…G time delay type and compare the short duration trip characteristics of your OCPD to that of the SI’s breaker.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>If your OCPD will trip “sooner” than the SI’s breaker you may see nuisance tripping of your OCPD during high surge events.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>There might be a parameter to limit the maximum discharge (surge) current but I could not find it in my admittedly quick skim of the SI manual.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>If you do not foresee very high surge loads (motor starting) this will not be an issue.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>48 kVA seems like one heck of a surge but, then again, I have not seen the customer’s home </span><span style='font-size:11.0pt;font-family:Wingdings;color:#1F497D'>J</span><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'><o:p> </o:p></span></p><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Best Regards,<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'>John Berdner<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>General Manager, North America<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'><img alt=SmallBannerPictEngnew border=0 height=113 id="Picture_x0020_1" src="cid:image001.jpg@01CE09F2.47122470" width=468><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'>SolarEdge Technologies, Inc.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>3347 Gateway Boulevard, Fremont CA 94538 USA </span><b><i><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#C00000'>(*Please note of our new address.)</span></i></b><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><br>T: 510.498.3200, X 747<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>M: 530.277.4894 <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>Allan Sindelar<br><b>Sent:</b> Wednesday, February 13, 2013 1:41 PM<br><b>To:</b> RE-wrenches<br><b>Subject:</b> Re: [RE-wrenches] Sunny Island DC wire size<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal style='margin-bottom:12.0pt'>John (and other Wrenches),<br>I read with great interest this post about Sunny Island breaker size. We are about to install a large semi-off grid system for a wealthy and eccentric customer. The system has 17kW of PV, and four SI5048 inverter/chargers, along with an Outback Radian serving as an inverter only to some separate protected circuits. The system has utility backup power available as well as a backup 30kW generator, but for a complicated reason the system can't be set to feed back into the grid; the SIs' sell function will be disabled.<br><br>The four SIs are set up as a pair on each 120V phase, as SMA allows. After consultation with SMA tech support, I have designed each SI to be on a 125A dc breaker. This is done to keep the total protected ampacity of the dc battery cabling and bussing to 850 amps (125 A x 4 = 500 A, plus 175 A x 2 for the Radian, all passing through a common 1,000 A shunt to allow accurate SOC metering). It's hard enough to address battery cabling and shunting with 850 amps; with 175 A dc breakers the total would be 1,050 amps, and with 250 A dc breakers the total would be 1,350 amps. <br><br>Given that the loads supplied are residential, primarily electronic and resistive, and thus few if any large surges, and given that the inverters on each phase are paralleled, how much should I worry about the 125a dc breaker size? Are there SI programming settings that I should know about to better protect against nuisance tripping?<br><br>Thank you,<br>Allan<o:p></o:p></p><div><p class=MsoNormal style='margin-bottom:12.0pt'><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>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></p></div><p class=MsoNormal>On 2/4/2013 1:29 PM, John Berdner wrote:<o:p></o:p></p></div><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><pre>Ryan:<o:p></o:p></pre><pre>Not sure what is in the manual now but...The lugs in the SI 5048U are dual 2/0.<o:p></o:p></pre><pre><o:p> </o:p></pre><pre>We had to use parallel AWG #1 because we kind of painted ourselves into a corner.<o:p></o:p></pre><pre>The breaker in the SI ended up being 250 Amps, the conduit fitting was only 1.5" and the wire bending space was too small for a 3/0.<o:p></o:p></pre><pre>The only way to get enough Ampacity in a 1.5" conduit and that wire bending space was to go with dual #1's.<o:p></o:p></pre><pre><o:p> </o:p></pre><pre>The 250 Amp breaker was used just to get enough current for the very short duration surges without tripping the breaker (12kW per SI).<o:p></o:p></pre><pre>If not for this a 200 A breaker would have been fine.<o:p></o:p></pre><pre><o:p> </o:p></pre><pre>Note that the actual full power ampacity required for normal operation is 5kW @ 40 Vdc = 125 Amps continuous.<o:p></o:p></pre><pre>It is the high surge loads that require more current.<o:p></o:p></pre><pre>I run mine with a single 2/0 and we have never even come close to hitting full power.<o:p></o:p></pre><pre>Worst case current is typically while charging not when inverting and I set the current limit so that I do not exceed ampacity of 2/0.<o:p></o:p></pre><pre>In my experience it takes >= 14kW generator to drive a pair of SI's to full power while charging<o:p></o:p></pre><pre><o:p> </o:p></pre><pre>Best Regards,<o:p></o:p></pre><pre><o:p> </o:p></pre><pre>John Berdner<o:p></o:p></pre><pre>General Manager, North America<o:p></o:p></pre><pre>SolarEdge Technologies, Inc.<o:p></o:p></pre><pre>3347 Gateway Boulevard, Fremont CA 94538 USA (*Please note of our new address.)<o:p></o:p></pre><pre>T: 510.498.3200, X 747<o:p></o:p></pre><pre>M: 530.277.4894<o:p></o:p></pre><pre><o:p> </o:p></pre></blockquote></div></DIV>
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