[Resolved] Photon Dead After Low VIN

Hello Particle Community,
I have been enjoying the products that Spark / Particle has made, unfortunately all of my devices ( Currently 3 SparkCores and 1 Photon [ Now ] ) have ened up frying one way or the other. Most of the time due to Voltage Regulation issues on the sparkcore with and without external regulation added as a precaution. Anywho, Sparkcores aside and there issues, this Friday I received the Photon and wanted to document what happened to mine.

Research :
Before I did anything with it I went and read Photon’s Documentation ( Link Below )
Please Note that I did not see any Min Voltage for VIN

Test :
Powered the photon with a Li-Ion Cell, ( Li-Ion 4v1 Max to 3v3 Min ), Thinking it will work just Fine. Powered the Photon for a full Day without issue coding to track solar data. I had it reading and sending voltage and battery percentage over the web just fine, Until the last update i got early in the morning stating that the battery was at 15% left. Refreshed the Page to see if it would update, never responded, the rest went down hill after that.

Result :
Last Publish that was sent to me was 15% Battery ~3v42 ( Calculation below )
So, Power Your Photon with 3v5 or Higher, Yes the Photon has a MIN VOLTAGE IN RATING

Photon Use Note : Voltage Read From Resistor Divided Circuit & Li-Ion Max and Min Voltage.

Calculations :
PercentageofBatteryLeft = (VoltageRead - Voltage_min) / (Voltage_max - Voltage_min) * 100
PercentageofBatteryLeft = (3.42 - 3.3) / (4.1 - 3.3) * 100
PercentageofBatteryLeft = (0.12) / (0.8) * 100
PercentageofBatteryLeft = (0.15) * 100
PercentageofBatteryLeft = 15 %

Conclusion :
I Hope this helps with others projects!

Power Resources / Links :

Gathered From Above Links (Page 4 in the PDF and Right on the Digikey Page) :
2v5 = Absolute Min Voltage
3v5 = Absolute Min Voltage when 3v3 Fixed Regulating (“VIN = 3.5 to 5.5V, VOUT = 3.3V 0A < IOUT < 600mA”)

Let the Documentation Reflect a 3v5 VIN Min value rather than blank for other Users.

Have a Great Day.

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When you say the photon is dead, it is entirely unresponsive when connected to a 5v source? Can you try invoking the bootloader modes, such as DFU mode and see if there is a response?

cc: @BDub

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I Don’t know about you but when I mention Photon being Dead Means no response what so ever…
Power Reg Heats up to untouchable state in about 15 Seconds… + no lights or anything.
I would rather not plug in for i fear the heat will cause more damage correct?

Hey @MrRetupmoc42, great post! Sorry you had to find the minimum operating voltage through trial and error, but it is included in the datasheet. See the first rating here: (Supply Input Voltage (VIN)

Looking at your picture there, it appears that there is extra solder on the VIN and adjacent GND pin. Did you solder anything to those? Any chance there is a short between VIN and GND or 3V3 and GND. If you can check with an ohm meter that would be helpful.

What kind of load did you have on the various I/O pins when the VIN dipped below 3.6V? I’ll see if I can replicate your failure.


Here is the info you requested…

Pictures of me Using it are on Insta…

Pin A0 was Photon Battery Input using a 1/2 resistor divider ( 4v1 Max / 2 = 2v05 )
Pin A1 was Solar Panel Input using a 1/5 resistor divider ( 15v0 Max / 5 = 3v0 )
Pin A2 was Solar Battery Input using a 1/4 resistor divider ( 13v0 Max / 4 = 3v25 )

Pictures Verify : No soldering to the controller, it was in a breadboard…
Continuity is False and Reading ~13.5 M OHM between VIN and GND
Continuity is True and Reading ~1.0 OHM between 3v3 and GND

Below is another Picture of the heat marks on the board ( around Vin, 3v3, and A0. )
Note : I was also using a ufl antenna with this seems to have heat marks around there to.

EDIT: As for Load I had no load on any pins… was just reading voltage.

Thanks @MrRetupmoc42, please check your PMs. I’m going to send you some instructions on how to proceed.

Thanks alot for your help,

Ill continue to code and build up my wireless coverage for the photon’s ill be ordering while waiting for them.
Solar Powered Monitoring Tools is the End Goal.

Again Thanks for the Info, And I Hope this Voltage Regulator Setback is sorted out easily for you guys.

@BDub and @MrRetupmoc42, for the sake of closing this topic, were you able to revive your devices? Can you add some closure please :blush:

After discussing with @BDub, the outcome of @MrRetupmoc42’s challenge was best addressed through a replacement by Particle including the return of the faulty device so a post-mortem would be done for continual quality improvement. Thanks @MrRetupmoc42 for your patience! I’ll tag this topic as solved :smiley:

@MrRetupmoc42 were you powering the Photon via VIN and GND using a 1 Cell Lipo battery?

Yes that Config is right but, I was using a Li-Ion Battery ( 3v3 - 4v1 ) and it dyed overnight, when i tested it showed 1v75 cross the cell…

@peekay123, Thanks for the closure, I have not been able to revive the photon, shall i send back the unit or attempt to hack on a 3v3 Regulator?

@MrRetupmoc42, I would follow @BDub’s instructions and return the faulty units.

Hi @BDub,

I guess I don’t understand the resolution of this topic. If you supply less than 3.6v on Vin is the expected behavior that the regulator gets fried? Or is it just that @MrRetupmoc42 had a regulator that went bad and drained his batteries when it was unattended? Was the drained batteries the cause or the effect here?

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I can’t be sure what happened to this dead photon, which is why I’d like to do a port mortem on it. Simply lowering the input voltage to the SMPS should not kill it, it should just turn off below 3.6V.

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That’s what I was hoping you would say. I am glad that it is not the case that the Photon burns itself up on a brown out.

ps. I would also have accepted “it may behave erratically below 3.6V.” :smile:


Hey I am really kind of caught off guard by this issue. I am using 3 AAA batteries to power my product. My understanding with the old core was that it had the ability to transmit data up until about when its batteries where drained down to 3.0v.

If the Photon cannot be relied upon below 3.6v this really significantly effects our battery life?

Am I misunderstanding this issue?

Yes, no, maybe? What are your thoughts?

Two separate issues I think: low voltage suspected to damage a photon (haven’t investigated yet), and which device (Core or Photon) will last longer running the same code when powered via 3 AAA batteries?

Would you please open up a separate topic for that so we can keep this one related to the low voltage issue?

@BDub, I have a nice programmable bench supply I can use to power a Photon and drop the voltage on it. Will test tonight hopefully.

@peekay123 Just tested this multiple times and as VIN drops from 5V to 3V, current goes up on VIN from 76mA to 112mA. Below 3.6V on VIN, the 3V3 output starts to drop out of regulation at 3.3V. Despite this, the STM32 and Broadcom radio will still operate. At 3.28V on VIN, 3V3 is 3.0V; this is the minimum spec for the PØ/P1. However, the STM32 will operate below this, so if Wi-Fi is off, this should still be considered ok. That said, the Broadcom radio will maintain a Wi-Fi connection with VIN at 3.0V (3V3 is 2.7V at this point). The RGB LED will noticeably dim. Code will stop executing at approximately 1.8V on 3V3 which is 2.2V on VIN. Nothing was damaged dropping this VIN voltage repeatedly.


The device has been shipped from our wearhouse to Particle, USPS Tracking ID below:


Plus I purchased another 5 Photons this week.

Untill i can trust that the photon can run off a li-ion or lipo, I will be voltage regulating 12v from the solar battery, down to 5v0 and pumping that into VIN, unless there is an issue with direct 5v0 into the photon for indefinate amount of time. But seeing as it ran nicely on USB i doubt there would be an issue.

Thanks Particle

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