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<p class="MsoNormal"><span style="font-size:11.0pt">To further David’s assessment of the Tigo TS4-A-F devices. I looked into an issue about a year or two ago with failed Tigo units suffering thermal damage on multiple small commercial rooftop sites. It appears
that the issue is crosstalk on the power line carrier signal. When the crosstalk occurs, the device does not receive the keep alive signal in the required 12 seconds and opens the output of the device. By opening the active MOSFET switch, this opening is
actually done slowly so as not to create large surges/arcing, it creates heat in the MOSFET/ device. Additionally, a ceramic high power bleed down resistor bleeds down the module charge. Imagine the solar module as a big capacitor plus inductive energy in
the cabling, these reactive components need to be bled down to below 30V within 30 seconds to keep that voltage below the NEC requirements. So when the unit performs the shut down, it has to disapate a little heat to open the circuit without arcing and from
the stored charge in the reactive components of the module. If the TS4-A-F is getting crosstalk and turning on and off rapidly, then the unit starts to get hot and eventually melts the device. This is specific to the TS4-A-F and the dual unit because they
are using PLC to communicate. Most of the other Tigo products are using a wireless communication, and not susceptible to the same type of interference. Tigo has lots of restrictions on the install to limit interference. I believe the issue is more prevalent
when you have multiple inverters sending out non synchronous RSS signals and the homerun wiring running in same conduit. Which is typical if you have several string inverters all dropping the DC down to an AC/DC conduit trough. If the RSS communication gets
jumbled to the Tigo unit under the module, it can turn the unit on and off. Exactly which unit will vary according to the noise and interference of the moment.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">I’ll interject here that I don’t have much experience with this product, nor the optimizer units, so I can’t speak to failures regarding the wireless based units nor do I have experience with utilizing the
TS4-A-F in the proper Tigo recommended synchronous signal booster and isolated conduit runs. Sounds like David had things installed proper and still saw a multitude of failures.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Mike Kocsmiersky<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">E3 Consulting<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> RE-wrenches <re-wrenches-bounces@lists.re-wrenches.org>
<b>On Behalf Of </b>David Buckner via RE-wrenches<br>
<b>Sent:</b> Thursday, November 20, 2025 12:03 PM<br>
<b>To:</b> william@millersolar.com; RE-wrenches <re-wrenches@lists.re-wrenches.org><br>
<b>Cc:</b> David Buckner <dbuckner@solaresystems.com><br>
<b>Subject:</b> Re: [RE-wrenches] Tigo TS4-A-F<o:p></o:p></span></p>
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<p align="center" style="text-align:center"><strong><span style="font-size:13.5pt;font-family:"Aptos",sans-serif;color:black">WARNING:
</span></strong><em><b><span style="font-size:13.5pt;font-family:"Aptos",sans-serif;color:black">This email originated from outside your organization.</span></b></em><span style="color:black">
<br>
</span><span style="font-size:10.0pt;color:black">Do not click links or open attachments unless you recognize the sender and know the contents are safe.<br>
If you have <strong><span style="font-family:"Aptos",sans-serif">ANY</span></strong> reason to doubt the authenticity of this message, contact IT before you open or click on anything.</span><o:p></o:p></p>
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<p class="MsoNormal" style="line-height:21.0pt"><b><span style="color:black">Evidence of failures and related issues</span></b><span style="color:black"><o:p></o:p></span></p>
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<b>Overheating and fire:</b> Multiple sources, including court documents, describe Tigo RSDs that showed signs of extreme overheating, melting, or being completely incinerated.<o:p></o:p></li><li class="MsoNormal" style="color:black;margin-bottom:9.0pt;mso-list:l1 level1 lfo1;list-style-position:initial">
<b>Legal action:</b> A lawsuit was filed against Tigo Energy alleging their RSDs posed a clear threat of death, injury, and property damage, with plaintiffs shutting down their own systems as a result.<o:p></o:p></li></ul>
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<p class="MsoNormal"><b><span style="color:black">Systemic problems:</span></b><span style="color:black"> Some reports suggest that failures are not isolated, with multiple devices failing across different projects. <o:p></o:p></span></p>
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<b>Allegations of a cover-up:</b> The aforementioned lawsuit includes claims that Tigo was aware of risks and failed to adequately warn customers, suggesting a cover-up was in progress,
<u><span style="color:#99C3FF"><a href="https://www.courthousenews.com/wp-content/uploads/2024/11/2024-29-3-13-14-13-2fb45a16-f38b-4ab2-bfe6-c4ba492b4ab4-2.pdf" target="_blank"><span style="color:#99C3FF">notes Courthouse News</span></a></span></u>. <o:p></o:p></li></ul>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black"> David Buckner <<a href="mailto:dbuckner@solaresystems.com">dbuckner@solaresystems.com</a>><br>
<b>Sent:</b> Thursday, November 20, 2025 11:32 AM<br>
<b>To:</b> <a href="mailto:william@millersolar.com">william@millersolar.com</a> <<a href="mailto:william@millersolar.com">william@millersolar.com</a>>; RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org">re-wrenches@lists.re-wrenches.org</a>><br>
<b>Cc:</b> Nick Lucchese <<a href="mailto:lucchesesolar@gmail.com">lucchesesolar@gmail.com</a>><br>
<b>Subject:</b> Re: [RE-wrenches] Tigo TS4-A-F</span> <o:p></o:p></p>
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<p class="MsoNormal"><span style="color:black">We have a multitude of these same issues with the TS40-A-F. We followed every new guideline from Tigo in order to avoid corrupted signals but still had issues. After a hot breezy day in NJ last year caused a
Tigo failure to spread the roof caught on fire and caused millions in damage. Thankfully no one was injured. We spent the rest of 2024 pulling 6 MW's of Tigos off of other roofs for this customer. I have heard multiple stories of similar issues for many
very experienced installers.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="color:black">David Buckner<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="color:black">SES<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-family:"Calibri",sans-serif;color:black">From:</span></b><span style="font-family:"Calibri",sans-serif;color:black"> RE-wrenches <<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a>>
on behalf of Nick Lucchese via RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org">re-wrenches@lists.re-wrenches.org</a>><br>
<b>Sent:</b> Wednesday, November 19, 2025 12:11 PM<br>
<b>To:</b> <a href="mailto:william@millersolar.com">william@millersolar.com</a> <<a href="mailto:william@millersolar.com">william@millersolar.com</a>>; RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org">re-wrenches@lists.re-wrenches.org</a>><br>
<b>Cc:</b> Nick Lucchese <<a href="mailto:lucchesesolar@gmail.com">lucchesesolar@gmail.com</a>><br>
<b>Subject:</b> Re: [RE-wrenches] Tigo TS4-A-F <o:p></o:p></span></p>
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<p class="MsoNormal" style="background:#FFEB9C"><span style="color:black">CAUTION: External Email.</span><o:p></o:p></p>
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<p class="MsoNormal">Appears that Zonna still has quite a few in stock. Feeling foolish to purchase more after having a TS4-2F fail into a pile of molten plastic and ruin a 405 watt bifacial module that I can no longer find a replacement for. What other options
do we have for small DC coupled arrays on residential rooftops though? Not the most inspiring times to be installing rooftop PV. Hopefully I'll start having better luck with the single module units. Numerous times I've had units become bricked and not pass
module voltage but this is the first time I've had this type of catastrophic failure that also inconveniently cost me the module.<o:p></o:p></p>
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<p class="MsoNormal">Nick<o:p></o:p></p>
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<p class="MsoNormal">On Mon, Nov 17, 2025 at 7:10<span style="font-family:"Arial",sans-serif"> </span>PM William Miller via RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org">re-wrenches@lists.re-wrenches.org</a>> wrote:<o:p></o:p></p>
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<p style="mso-margin-top-alt:12.0pt;margin-right:0in;margin-bottom:12.0pt;margin-left:0in">
<span style="font-family:"Verdana",sans-serif">Friends:</span><o:p></o:p></p>
<p style="mso-margin-top-alt:12.0pt;margin-right:0in;margin-bottom:12.0pt;margin-left:0in">
<span style="font-family:"Verdana",sans-serif"> </span><o:p></o:p></p>
<p style="mso-margin-top-alt:12.0pt;margin-right:0in;margin-bottom:12.0pt;margin-left:0in">
<span style="font-family:"Verdana",sans-serif">I am having trouble locating these RSDs. Very few vendors appear to have these and I can’t get any to call back and verify they have them. I can’t get Tigo to return my calls. Does anyone know if these are discontinued?</span><o:p></o:p></p>
<p style="mso-margin-top-alt:12.0pt;margin-right:0in;margin-bottom:12.0pt;margin-left:0in">
<span style="font-family:"Verdana",sans-serif"> </span><o:p></o:p></p>
<p style="mso-margin-top-alt:12.0pt;margin-right:0in;margin-bottom:12.0pt;margin-left:0in">
<span style="font-family:"Verdana",sans-serif">What are the rest of you doing for rapid shutdown? I don’t trust Alps: I have heard too many horror stories. It seems the form factor is too small to contain arc suppression measures.</span><o:p></o:p></p>
<p style="mso-margin-top-alt:12.0pt;margin-right:0in;margin-bottom:12.0pt;margin-left:0in">
<span style="font-family:"Verdana",sans-serif"> </span><o:p></o:p></p>
<p style="mso-margin-top-alt:12.0pt;margin-right:0in;margin-bottom:12.0pt;margin-left:0in">
<span style="font-family:"Verdana",sans-serif">Somewhere I saw as an alternative the Tigo TS4-A-O. These are optimizers. I worry these will fight with the MPPT algorithm in the inverter or charge controller. There is also the TS4-A-S which has shutdown and
monitoring.</span><o:p></o:p></p>
<p style="mso-margin-top-alt:12.0pt;margin-right:0in;margin-bottom:12.0pt;margin-left:0in">
<span style="font-family:"Verdana",sans-serif"> </span><o:p></o:p></p>
<p style="mso-margin-top-alt:12.0pt;margin-right:0in;margin-bottom:12.0pt;margin-left:0in">
<span style="font-family:"Verdana",sans-serif">All input is welcome an appreciated. Thanks in advance.</span><o:p></o:p></p>
<p style="mso-margin-top-alt:12.0pt;margin-right:0in;margin-bottom:12.0pt;margin-left:0in">
<span style="font-family:"Verdana",sans-serif"> </span><o:p></o:p></p>
<p style="mso-margin-top-alt:12.0pt;margin-right:0in;margin-bottom:12.0pt;margin-left:0in">
<span style="font-family:"Verdana",sans-serif">William</span><o:p></o:p></p>
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<span style="font-family:"Verdana",sans-serif"> </span><o:p></o:p></p>
<p style="mso-margin-top-alt:12.0pt;margin-right:0in;margin-bottom:12.0pt;margin-left:0in">
<span style="font-family:"Arial",sans-serif">Miller Solar</span><o:p></o:p></p>
<p style="mso-margin-top-alt:12.0pt;margin-right:0in;margin-bottom:12.0pt;margin-left:0in">
<span style="font-family:"Arial",sans-serif">17395 Oak Road, Atascadero, CA 93422</span><o:p></o:p></p>
<p style="mso-margin-top-alt:12.0pt;margin-right:0in;margin-bottom:12.0pt;margin-left:0in">
<span style="font-family:"Arial",sans-serif">805-438-5600</span><o:p></o:p></p>
<p><span style="font-family:"Arial",sans-serif"><a href="http://www.millersolar.com/">www.millersolar.com</a></span><o:p></o:p></p>
<p style="mso-margin-top-alt:12.0pt;margin-right:0in;margin-bottom:12.0pt;margin-left:0in">
<span style="font-family:"Arial",sans-serif">CA Lic. 773985</span><o:p></o:p></p>
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<o:p></o:p></p>
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<p class="MsoNormal">_______________________________________________<br>
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