[RE-wrenches] Tigo TS4-A-F

Thu Nov 20 09:03:15 PST 2025

Evidence of failures and related issues

  *   Overheating and fire: Multiple sources, including court documents, describe Tigo RSDs that showed signs of extreme overheating, melting, or being completely incinerated.
  *   Legal action: 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.

Systemic problems: Some reports suggest that failures are not isolated, with multiple devices failing across different projects.

  *   Allegations of a cover-up: The aforementioned lawsuit includes claims that Tigo was aware of risks and failed to adequately warn customers, suggesting a cover-up was in progress, notes Courthouse News<https://www.courthousenews.com/wp-content/uploads/2024/11/2024-29-3-13-14-13-2fb45a16-f38b-4ab2-bfe6-c4ba492b4ab4-2.pdf>.

________________________________
From: David Buckner <dbuckner at solaresystems.com>
Sent: Thursday, November 20, 2025 11:32 AM
To: william at millersolar.com <william at millersolar.com>; RE-wrenches <re-wrenches at lists.re-wrenches.org>
Cc: Nick Lucchese <lucchesesolar at gmail.com>
Subject: Re: [RE-wrenches] Tigo TS4-A-F

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.

David Buckner
SES

________________________________
From: RE-wrenches <re-wrenches-bounces at lists.re-wrenches.org> on behalf of Nick Lucchese via RE-wrenches <re-wrenches at lists.re-wrenches.org>
Sent: Wednesday, November 19, 2025 12:11 PM
To: william at millersolar.com <william at millersolar.com>; RE-wrenches <re-wrenches at lists.re-wrenches.org>
Cc: Nick Lucchese <lucchesesolar at gmail.com>
Subject: Re: [RE-wrenches] Tigo TS4-A-F

CAUTION: External Email.
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.

Nick

On Mon, Nov 17, 2025 at 7:10 PM William Miller via RE-wrenches <re-wrenches at lists.re-wrenches.org<mailto:re-wrenches at lists.re-wrenches.org>> wrote:

Friends:

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?

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.

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.

All input is welcome an appreciated.  Thanks in advance.

William

Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com<http://www.millersolar.com/>

CA Lic. 773985

_______________________________________________
List sponsored by Redwood Alliance

Pay optional member dues here: http://re-wrenches.org<http://re-wrenches.org/>

List Address: RE-wrenches at lists.re-wrenches.org<mailto:RE-wrenches at lists.re-wrenches.org>

Change listserver email address & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org

There are two list archives for searching. When one doesn't work, try the other:
https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/
http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org

List rules & etiquette:
http://www.re-wrenches.org/etiquette.htm

Check out or update participant bios:
http://www.members.re-wrenches.org<http://www.members.re-wrenches.org/>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20251120/d66be4b8/attachment-0001.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Tigo Energy Civil Action 3-26-24.pdf
Type: application/pdf
Size: 195427 bytes
Desc: Tigo Energy Civil Action 3-26-24.pdf
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20251120/d66be4b8/attachment-0001.pdf>