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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Drake<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>We use Magnums Router it has a Voltage based Aux relay. We then control a 2 pole SSR (Actually a 3 phase triac as that is a part we stock) to disconnect the Grid Tie inverter. I tend to take the mindset that this is an Emergency system so the concern of 3 stage charging when in actual AC coupled mode is truly not important. If this was a normal off grid system doing AC coupling than it would be a different story.<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'>Ryan<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"'>Ryan Stankevitz<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>Technical Support Manager<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>MidNite Solar Inc.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><a href="mailto:ryan@midnitesolar.com" target="_blank">ryan@midnitesolar.com</a><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><a href="tel:360-403-7207%20XT%20151" target="_blank">360-403-7207 XT 151</a><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>Skype ID ryan.midnite<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'><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><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"'>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>Drake<br><b>Sent:</b> Friday, March 08, 2013 9:40 AM<br><b>To:</b> RE-wrenches<br><b>Subject:</b> Re: [RE-wrenches] AC Coupled Magnum Issue<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thank you to all who responded to this post. <br><br>Larry, that sounds like a great potential solution. That will put the frequency shift in line with where the battery cutoff voltage needs to be. The frequency shift happens 2 volts above the absorption charge set point. My only issue with the solution is the 1 1/2 hour round trip to the site (it could be worse). Maybe Concorde can give me information that will allow me to set up the charge parameters without having to tweak. <br><br>Allan, dump loads are a great way to go, for sure. The tech I spoke to at Magnum recommended the relay as a fail safe for the frequency shift. When the issue of the inverter frequency shifting at 2 volts above the absorption charge set point came up, the relay became the primary protective device for the AGM batteries. <br><br>We didn't use diversion loads since this is a backup system, and will probably only operate a few days per year. The inverter should maintain the batteries rather than the solar. We used the Morningstar relay driver, in part, to allow dump loads to be added if desired. <br><br>Another solution was offered by APRS World, LLC. They likely can build products that would trigger relays using the temperature compensated data from the Magnum Network. <br><br>It would sure simplify life it Magnum could add an axillary relay. Would that require putting the inverter, or entire line of inverters, back into UL for re-approval? <br><br>Drake <br><br> <br>At 05:36 PM 3/7/2013, you wrote:<br><br><o:p></o:p></p><p class=MsoNormal>Meant to say, "You should tweak #3 & #4 above..."<br><br><br>Drake,<br><br>Charging an AGM battery does not have to occur at the maximum charge voltage allowable; you can charge at a lower voltage for longer periods of time and still achieve 100% SoC. Since you have grid power to work with, slow down the charge cycle.<br><br>Assuming you have a late model ME-RC and version 5 or higher inverter, you can custom program the charge voltages. Here's what I would do: <o:p></o:p></p><ol start=1 type=1><li class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1'>Go to Custom settings for battery type (setup menu 04). <o:p></o:p></li><li class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1'>Set the Absorb voltage for 26.8. <o:p></o:p></li><li class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1'>Set the Float for 26.4 <o:p></o:p></li><li class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1'>Set the absorb time to 8 hours <o:p></o:p></li><li class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1'>Be sure the charge rate( setup menu 05) is 100%. <o:p></o:p></li></ol><p class=MsoNormal><br>Near the end of the absorb charge cycle, measure the current going into the battery. If it is less than 0.2 amps/100AH capacity, the bank is full. You should #3 & #4 above until it works out for the low temp. comp. and charge time but it should work well.<br><br>If you are concerned about this lower voltage, set up a periodic equalize charge to 28.8.<br><br>Larry Crutcher<br>Starlight Solar Power Systems<br><br><br><br><br><br>On Mar 7, 2013, at 3:00 PM, Drake wrote:<br><br>Hello Wrenches,<br><br>I had an unexpected glitch in AC coupling a Magnum 4024 PAE inverter. The system utilizes AGM batteries, which (according to Concorde tech support) have a very strict upper voltage limit.<br><br>The relay used to stop the current input from the direct grid tie inverter, when battery voltage is high, is controlled by a Morningstar Relay Driver. The relay driver is set to shut off the charge at 28.8 volts.<br><br>The charger on the Magnum is set to charge the batteries to 28.6 volts. <br><br>The plan was to be able to charge batteries from the Magnum without tripping the AC connection between the grid tie inverter to the grid. The Magnum should charge to 28.6 volts, 0.2 volts below the relay driver's programmed trigger point. <br><br>There is one catch to using this approach. The Magnum inverter has a remote temperature sensor in the battery bank. The relay driver is not temperature corrected. Therefore, when the batteries are cold, the charging voltage goes up in the Magnum. This higher voltage trips the relay controlled by the driver, and disconnects the grid tie inverter from the grid. <br><br>I've played with the voltage set points, but the charge voltage on the Magnum would be too low for good battery maintenance. If these were liquid electrolyte batteries, I'd crank up the voltage on the relay driver. Since they are AGM batteries, it doesn't seem like a good idea to do that. <br><br>The work around for this at present is to; <o:p></o:p></p><ul type=disc><li class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l1 level1 lfo2'>Charge batteries at night in the winter <o:p></o:p></li><li class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l1 level1 lfo2'>No problem is expected in the summer <o:p></o:p></li></ul><p class=MsoNormal>The batteries are in an insulated box in a shed connected to the house. The inside of the battery box has a screened hole that is supposed to allow heated air into the box. This vent doesn't keep the batteries warm enough to prevent the problem. <br><br>Is there a temperature sensitive, voltage controlled relay or diver available? Has anyone used a temperature bulb with the relay driver in a way that could solve this problem? Has anyone else come up against this issue, and if so, what was your solution?<br><br>Thanks,<br><br>Drake <br><br><br>Drake Chamberlin<br><i>Athens Electric LLC<br>OH License 44810<br>CO License 3773<br>NABCEP Certified Solar PV Installer<br>740-448-7328<br></i><a href="http://athens-electric.com/">http://athens-electric.com/</a> <br>_______________________________________________<br>List sponsored by Home Power magazine<br><br>List Address: <a href="mailto:RE-wrenches@lists.re-wrenches.org">RE-wrenches@lists.re-wrenches.org</a><br><br>Change email address & settings:<br><a href="http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org">http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org</a> <br><br>List-Archive: <a href="http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org">http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org</a><br><br>List rules & etiquette:<br><a href="http://www.re-wrenches.org/etiquette.htm">www.re-wrenches.org/etiquette.htm</a><br><br>Check out participant bios:<br><a href="http://www.members.re-wrenches.org/">www.members.re-wrenches.org</a><br><br><br>_______________________________________________<br>List sponsored by Home Power magazine<br><br>List Address: <a href="mailto:RE-wrenches@lists.re-wrenches.org">RE-wrenches@lists.re-wrenches.org</a><br><br>Change email address & settings:<br><a href="http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org">http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org</a> <br><br>List-Archive: <a href="http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org">http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org</a><br><br>List rules & etiquette:<br><a href="http://www.re-wrenches.org/etiquette.htm">www.re-wrenches.org/etiquette.htm</a><br><br>Check out participant bios:<br><a href="http://www.members.re-wrenches.org/">www.members.re-wrenches.org</a><br><br><br>_______________________________________________<br>List sponsored by Home Power magazine<br><br>List Address: <a href="mailto:RE-wrenches@lists.re-wrenches.org">RE-wrenches@lists.re-wrenches.org</a><br><br>Change email address & settings:<br><a href="http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org">http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org</a> <br><br>List-Archive: <a href="http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org">http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org</a><br><br>List rules & etiquette:<br><a href="http://www.re-wrenches.org/etiquette.htm">www.re-wrenches.org/etiquette.htm</a><br><br>Check out participant bios:<br><a href="http://www.members.re-wrenches.org/">www.members.re-wrenches.org</a><o:p></o:p></p><div class=MsoNormal align=center style='text-align:center'><hr size=1 width="100%" noshade style='color:#A0A0A0' align=center></div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>No virus found in this message.<br>Checked by AVG - <a href="http://www.avg.com">www.avg.com</a><br>Version: 2013.0.2904 / Virus Database: 2641/6154 - Release Date: 03/07/13<o:p></o:p></p></div></body></html>