<div dir="ltr">Rick,<div>I was recently troubleshooting a similar problem. Open circuit voltage on all strings was as expected but under load one string was showing almost no power. Tracked this down to a failed APSmart device which had clear signs of thermal damage. Pictures 1.1 and 1.2. .<div>A second failed unit some months later had a thermal failure and this one toasted the module. Picture 2.1.</div><div><br></div><div>These devices can make it difficult to do any meaningful string level testing. The devices output a nominal 0.7 volts in open circuit conditions. That documentation says this voltage reading is <u>+</u> 25%, so in theory you could have a number of devices which were not working and your string voltage would not indicate that.</div><div><br></div><div>APSmart does make a test device which can help you verify the functionality. The device is called RSD-EYE+ Detector. You can contact YI Kang , <b><span style="font-family:inherit;color:rgb(127,127,127);border:1pt none windowtext;padding:0in">APPLICATION & TECHNICAL SUPPORT MANAGER,</span></b></div><div><b><span style="font-family:inherit;color:rgb(127,127,127);border:1pt none windowtext;padding:0in">MLRSD </span></b>at APSmart for additional information. <span style="color:rgb(104,104,108);font-size:12px"> </span><span style="color:rgb(104,104,108);font-size:12px">737.218.8486</span></div><div><img src="cid:ii_kq6t1n2s0" alt="FailedAPSmart1.2.jpg" width="355" height="473"><br><div><div dir="ltr" data-smartmail="gmail_signature"><div dir="ltr"><div><img src="cid:ii_kq6t1n321" alt="FailedAPSmart2.1.jpg" width="355" height="473"><br><img src="cid:ii_kq6t1n392" alt="FailedAPSmart1.1.jpg" width="355" height="473"><br><div>With Kind Regards<div>Carl Adams, President</div><div>SunRock Solar, LLC</div>513.290.9072 (mobile)</div><div>513.766.6025 (office)</div><br></div></div></div></div><br></div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Jun 21, 2021 at 11:55 AM Lloyd Hoffstatter <<a href="mailto:lloyd@sunstruckconsulting.com" target="_blank">lloyd@sunstruckconsulting.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
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Rick,</div>
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I would check with SMA to make sure you have the latest firmware.</div>
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Best regards,</div>
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Lloyd</div>
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Lloyd Hoffstatter</div>
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Sunstruck Consulting</div>
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<div id="gmail-m_7432443947316214792gmail-m_1138851491947336934gmail-m_3567001989742486314gmail-m_-8526887617016525303divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> RE-wrenches <<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank">re-wrenches-bounces@lists.re-wrenches.org</a>> on behalf of <a href="mailto:rick@solshineenergy.com" target="_blank">rick@solshineenergy.com</a> <<a href="mailto:rick@solshineenergy.com" target="_blank">rick@solshineenergy.com</a>><br>
<b>Sent:</b> Monday, June 21, 2021 11:42:36 AM<br>
<b>To:</b> RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a>><br>
<b>Subject:</b> [RE-wrenches] RSD Troubleshooting Help</font>
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<div>Wrenches,<br>
<br>
I\u2019m in need of some troubleshooting help on a newly installed system with rapid shutdown. System consists 2 SMA SB5.0-1 SP-US-41 (RSD version), RSD devices are APS RSD-S-PLC. Each SB is configured with two strings of 9. Modules are REC Alpha 360s.
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This system was fully functional for about 1 week before things went awry. Initial symptoms were that one of the two strings read 0V 0A on the display while the other read ~315V, 5A. The RSD devices output ~700mV each when in the off mode (a nice verification
feature). I\u2019m reading the correct voltage - 6.75V - on both strings when in off mode. Once the Sunny Boy comes on line I\u2019m reading around 10V on the faulty string and the correct voltage - ~315V - on the other string.
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The above seems to indicate that each RSD is getting sufficient DC voltage from the module. Short of pulling each module and doing a visual check what else can I look at? How do you isolate a faulty RSD device?<br>
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And as luck would have it, everything is functional at the moment. <br>
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Thanks,<br>
<br>
rick brown<br>
SolShine Energy Alternatives, LLC<br>
Electrical & Solar Contracting Services<br>
<a href="http://www.SolShineEnergy.com" target="_blank">www.SolShineEnergy.com</a><br>
Check, Virginia 24072<br>
O: 540.235.3095<br>
M: 540.808.9502<br>
<br>
VA Class A Contractor Lic# 2705147660<br>
VA Master Electrician Lic# 2710062762<br>
VA Alternative Energy Systems Installer <br>
NABCEP Certified PV Installation Professional 110112-21<br>
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