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<FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:11pt'>Kirpal -<BR>
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I have had relatively bad experiences with the BP3160 line of modules, as stated previously in earlier wrenches contributions. We have had all sorts of problems with them, from the j-box actually blowing up (while the customer was working in the yard) to burn marks on the busbar of the front of the module, to burn marks on individual cells of the panels. I am attaching a product advisory from 2006 which sounds like it falls under your SX170 line of modules possibly.<BR>
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What BP has told us is that individual module failure is likely due to close range shading of the array from a nearby tree, chimney, or some other sharp silhouette that may cause more stress of the current through the cells without a voltage (the shaded modules). <BR>
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In my experience the fastest way to find a panel in these strings of 12 modules or less:<BR>
Step 1: Get individual string Voc [for your example, 362 and 312]<BR>
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Step 2: Cut string in 8 in half [312 in your case, yielding 170 and 132] <BR>
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Step 3: Cut string of 4 in half and do the same [yielding say 78 Voc and 54]<BR>
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Step 4: the two worst panels [say 78 Voc and 54] are one of the 54 Volt panels<BR>
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With four steps you have gotten your two worst modules in an array of 16 panels. Believe me, the Enphase inverters would utimately cut all of this troubleshooting wasted time out because at the end of the day BP only gives you like $100 per panel. That is to cover your time apologizing to the client, drive time, and troubleshooting time, not to mention time dealing with the warranty claim report, e-mailing BP, and packaging the module in a carton to send it back. If this is your first time dealing with such an issue, you have also just wasted your time driving to the site without a replacement panel. I would suggest that you demand BP to provide you with backup panels now for dealing with the issue at a financial loss to your company. For example, we now have seven panels which we rotate in and out of our 3,000+ BP3160s installed. This last quarter, we have had at least 15 more bad panels since I wrote the e-mail below; mostly now with only burn marks, but they were ready to go. Believe me, I would suggest spending more time on a class action lawsuit than trying to figure out bad diode problems; [I’m half kidding here, contact me offline if you are “<I>inspired</I>”]<BR>
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Here is an e-mail that I forwarded to a colleague of mine who wanted to bring this to UL’s attention due to his position in the solar industry and safety concern for module failure in the industry.<BR>
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“<FONT COLOR="#0000FF"><I>These photos are typical of about 20 of our 41 failed panels for which I have shown two of the more seriously failed panels at the j-box. I assume that the summer this is more likely to happen or in cold weather with a lot of irradiance. <BR>
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We are at almost a 1.5% failure rate [41 out of 3057] BP 3160 series panels installed since 2001. Also (and more importantly) inconveniencing 13% of our customers (13 out of 95 BP installations) with failed BP panels. We don't know the panels have failed unless they tell us either 1) they heard a noise and are smelling burnt rubber or electric wires, 2) their production has been cut in half, or 3) their anniversary card shows that they are not getting as much total output during the year. <BR>
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In essence, I was wondering what you thought our possibilities for pursuing entire array change-outs or litigation. At what point do manufacturers seem willing to change out an array, (2 out of 20 panels [10%], 5 out of 20 [25%]) etc.? In the mean time, we are trying to be proactive and the manufacturers are approving change-outs of panels with burn marks around the buss bar on the cell side of the junction box.”<BR>
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I have attached below the content of an e-mail confirming similar issues with this line of modules from our distributor, at the time.<BR>
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mes 2 centimes quoi,<BR>
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</SPAN></FONT><FONT SIZE="1"><FONT FACE="Verdana, Helvetica, Arial"><SPAN STYLE='font-size:9pt'>Greg Seelhorst<BR>
Installation Manager<BR>
NABCEP Certified Solar PV Installer</SPAN></FONT><FONT FACE="Monaco, Courier New"><SPAN STYLE='font-size:7.5pt'>®<BR>
</SPAN></FONT><FONT FACE="Verdana, Helvetica, Arial"><SPAN STYLE='font-size:9pt'>Solar Works<BR>
400 Morris Street, Suite C<BR>
Sebastopol, CA 95472<BR>
707-829-2518 (work)<BR>
707-849-6819 (cell)<BR>
707-829-8283 (fax)<BR>
CA Solar License (C-46) #878231<BR>
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<SPAN STYLE='font-size:11pt'><FONT FACE="Arial">BP Solar Product Advisory
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<SPAN STYLE='font-size:11pt'><FONT FACE="Arial">Dear Conergy Customer:<BR>
</FONT><FONT FACE="Geneva, Verdana, Helvetica, Arial"><BR>
</FONT><FONT FACE="Arial">BP Solar has identified a potential problem with certain BP Solar modules operating in specific installation environments and applications. Under the circumstances outlined in the attached BP Product Advisory (Advisory), there is a limited risk of overheating of the junction box, which can lead to roof damage and the potential for fire. Damage to UL790 Class A fire resistant roofs – such as typical asphalt shingle, metal, and tile roofs – is unlikely, and the current Advisory only concerns installations on non-fire resistant roofs.<BR>
</FONT><FONT FACE="Geneva, Verdana, Helvetica, Arial"><BR>
</FONT><FONT FACE="Arial">The problem has been traced to failed solder joints within the low profile junction box on MC connected modules, and failures tend to occur within the first few years of operation. Approximately 0.02% of US market modules are affected, including BP Solar 3, 4, and 5 Series modules and the SX line manufactured between 2002 and 2004. The Advisory is further limited to high voltage, grid-tie installations with open circuit voltages above 100 VDC, and where flammable materials are located within approximately 2 inches of the module. Please see the attached Advisory for the exact criteria used to determine affected installations.<BR>
</FONT><FONT FACE="Geneva, Verdana, Helvetica, Arial"><BR>
</FONT><FONT FACE="Arial">If any of your installations meet all of the criteria listed in the Advisory, please contact BP Solar directly at <a href="bpsolarwarranty@bp.com">bpsolarwarranty@bp.com</a> or call 1-800-891-2163. BP Solar will immediately arrange for system disconnection and inspection at their cost, and will also compensate for power lost.<BR>
</FONT><FONT FACE="Geneva, Verdana, Helvetica, Arial"><BR>
</FONT><FONT FACE="Arial"><I>Distributor X [name purposefully removed to protect the innocent] </I>stands ready to provide support to you, our customer, for any BP Solar product issues associated with products we distributed. Distributor X is committed to minimizing any hardships the Advisory may incur upon you and your clients, and to working with you and BP Solar to resolve any issues that may arise.<BR>
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On 11/12/08 8:03 PM, "Kirpal Khalsa" <<a href="solarworks@gmail.com">solarworks@gmail.com</a>> wrote:<BR>
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</FONT></SPAN><BLOCKQUOTE><SPAN STYLE='font-size:11pt'><FONT FACE="Calibri, Verdana, Helvetica, Arial">Chris......Less than 2 years.......<BR>
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On Wed, Nov 12, 2008 at 7:59 PM, Chris @ the Oasis <<a href="info@oasismontana.com">info@oasismontana.com</a>> wrote:<BR>
</FONT></SPAN><BLOCKQUOTE><SPAN STYLE='font-size:11pt'><FONT COLOR="#800000"><FONT FACE="Comic Sans MS">Hello Kirpal:<BR>
</FONT></FONT><FONT FACE="Calibri, Verdana, Helvetica, Arial"> <BR>
</FONT><FONT COLOR="#800000"><FONT FACE="Comic Sans MS">What is the relative age of these modules? For starters.... Just curious.<BR>
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</FONT><FONT COLOR="#000080"><FONT FACE="Comic Sans MS">Chris Daum<BR>
Oasis Montana Inc.<BR>
406-777-4309 local line<BR>
406-777-0830 fax<BR>
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<HR ALIGN=CENTER SIZE="3" WIDTH="100%"></FONT><FONT FACE="Tahoma, Verdana, Helvetica, Arial"><B>From:</B> <a href="re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a> [<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org">mailto:re-wrenches-bounces@lists.re-wrenches.org</a>] <B>On Behalf Of </B>Kirpal Khalsa<BR>
<B>Sent:</B> Wednesday, November 12, 2008 8:33 PM<BR>
<B>To:</B> RE-wrenches<BR>
<B>Subject:</B> Re: [RE-wrenches] Trouble Shooting Bad Diode<BR>
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Bill and all.......So we were at the site today and these were our findings:<BR>
We covered each solar panel with cardboard 1 at a time.....we continued to see the same lower voltage on string #2. String #1 had an expected Voc. <BR>
String 1 had a Voc of 368, String 2 had Voc of 312. <BR>
We decided to disconnect the entire string. Luckily the interconnects were accessible without physically removing the modules.......I love array's that are only 2 rows deep with service aisles all around.....<BR>
The system was 2 strings of 9 BP SX170's connected to a PVP2800XV. <BR>
Module nameplate Voc was 44V. Cell temp of the modules at time of measurement was roughly 85-90 degrees F. <BR>
all modules were in the 40.1-8 range....except module # 3 from the positive homerun side was 38.8V, module 6 was 36.6V and module 8 was 10V. <BR>
We had no trouble determining that module # 8 was defective......In these modules I believe that the entire 72 cells are in a series.string...(am i right?roughly .5+V per cell.).<BR>
Covering 1 module at a time did not give us any indication as to which panel was defective. The Voc with 1 module covered ranged from a low of 299VV to a high of 304V. This did not make sense to me as to reducing the string Voc from 312 to 304 by covering 1 module.........<BR>
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Anyhow........the 2 modules that had reduced voltages......1 with ~38V and 1 with ~36V......would you consider those defective? Worthy of trying to get BP to warranty those?<BR>
We will be filing a warranty claim on the single panel that is obviously defective.......<BR>
Thanks for your advice and input.....<BR>
Cheers,<BR>
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Kirpal Khalsa<BR>
Renewable Energy Systems<BR>
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On Fri, Oct 31, 2008 at 10:33 AM, Bill Brooks <<a href="billbrooks7@yahoo.com">billbrooks7@yahoo.com</a>> wrote:<BR>
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Kirpal,<BR>
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When you parallel, your voltages have to be the same, so you are correct in that assumption.<BR>
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Your assumption about the diodes is not correct. Diodes don't work like that. You could have a shorted module (all three diodes shorted) which would lower the Voc by one module. It looks like you have nearly two modules worth of problems. It could be a total of 5 bad diodes, but that would be weird. It could be you have a ground fault, and haven't tripped the GFP yet because of lower sunlight levels—(it has to be very low sun to stay under 1 amp). You also could have a wiring mistake, either because the factory reversed wired a module (rare, but it happens)—that would be 2 modules low; or, you could have skipped two modules somehow.<BR>
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It does seem like a quarter of the bad string is out. Your assumption about bad diodes could be correct, but it only affects the groups of cells its connected to. Each diode protects 24 cells—it looks like you have 5 diodes worth of loss. It could be in 2 modules, or up to 5 modules. <BR>
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The shading test is the best way to find bad diodes. Disconnect the bad string from the good one and take a piece of cardboard the dimension of the module. With your meter testing Voc on the back string, completely cover each module, one at a time. When the Voc is not affected by complete shading of a module, that module is completely bad. If the shaded module only loses a portion of one module's Voc, then you have one or two, of the three diodes, bad.<BR>
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This is a great opportunity to learn how to troubleshoot a PV array. Take the time, and the effort, to run through it carefully, learn the problems, and report back with your findings. It's a beautiful thing to learn something new.<BR>
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Bill.<BR>
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<B>From:</B> <a href="re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a> [<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org">mailto:re-wrenches-bounces@lists.re-wrenches.org</a>] <B>On Behalf Of </B>Kirpal Khalsa<BR>
<B>Sent:</B> Friday, October 31, 2008 10:43 AM<BR>
<B>To:</B> RE-wrenches<BR>
<B>Subject:</B> [RE-wrenches] Trouble Shooting Bad Diode<BR>
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Greetings all......I was hoping i could have someone help me confirm a troubled series string on a system we have installed.....<BR>
System consists of 16 BP 170 W 24V nominal modules......2 strings of 8 modules.....Vmp of each module is roughly 34V and Voc of each module is roughly 41V. One string is under-producing......String 1 Voc is 346V and String 2 Voc is 272V. String 1 Vmp under load is 270V and String 2 Vmp underload is 270V. I am hypothesizing that String 2 has a bad diode on the 3rd panel in and is reducing the Voc of that string by th 2 panels ahead of it in the string. I am hoping to figure this out without removing the entire string and checking each panel if possible.....<BR>
I think the Vmp is equal due to the fact that both strings are paralleled in the inverter and the 1st string is being pulled to the same level V as the 2nd string under load......Is my logic good?<BR>
Thanks for the help and advice.....<BR>
Cheers,<BR>
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