[RE-wrenches] Tigo TS4-A-F

Thu Nov 20 18:26:59 PST 2025

We saw one APSMART fail.  It was a dual-module unit.
      it failed In the closed position.  At the inverter, the voltage we
measured was 2 modules in series plus the RSD safety voltage for the rest
of the string.

On Thu, Nov 20, 2025 at 9:54 AM Tyrone Houck via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:

> Has anybody had any failures of APSmart RSD-S-PLC's? I asked this before
> and got no responses. I have had no issues myself and they seem consistent
> and straightforward.
>
>
>
>
> On Thu, Nov 20, 2025, 9:06 AM David Buckner via RE-wrenches <
> re-wrenches at lists.re-wrenches.org> wrote:
>
>> 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> 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
>>
>> CA Lic. 773985
>>
>>
>>
>>
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