Olimex Support Forum

Microcontrollers => ESP32 => Topic started by: Stephane80 on November 10, 2019, 07:52:02 PM

Title: ESP32-POE-ISO temperature
Post by: Stephane80 on November 10, 2019, 07:52:02 PM
Hello,
I bought an ESP32-POE-ISO but it seems to me relatively hot with poe.
Can you tell me if it's normal
And what is the normal temperature range of use?
To be able to use it without risk
Thanks in advance for your help.
Best regards, Stephane
Title: Re: ESP32-POE-ISO temperature
Post by: LubOlimex on November 11, 2019, 09:42:16 AM
Overall it is normal for this board to get a little hotter than usual electronics but make sure that you are not attempting to draw more than 200mA (300mA if no battery is used) from the 5V line for additional electronics or parts.

Can you tell me which component exactly gets the hottest? Maybe look the component's datasheet and find if it is in the proper range of operation.
Title: Re: ESP32-POE-ISO temperature
Post by: Stephane80 on November 11, 2019, 11:55:49 AM
Hello ,
I just have a SN65HVD230 (can module) plugged in
like this:
(https://images-na.ssl-images-amazon.com/images/I/41Ib2fB%2BltL.jpg)
I will try to take a thermal image of the esp

Title: Re: ESP32-POE-ISO temperature
Post by: Stephane80 on November 11, 2019, 12:29:04 PM
(https://i.imgur.com/sEpGKdy.jpg)
Title: Re: ESP32-POE-ISO temperature
Post by: Stephane80 on November 11, 2019, 12:39:50 PM
(https://i.imgur.com/YCwT4Mk.jpg)
Title: Re: ESP32-POE-ISO temperature
Post by: LubOlimex on November 11, 2019, 03:30:06 PM
Hmmm, can you give me some more details about your setup so I can try to repeat same setup here and measure the temperature of few boards.

Did you test only one board or a few boards and all show similar temperatures?

How is the board powered? If it is via PoE can you give me more details about the equipment that feeds the power.

What is the software utilizing - Ethernet, UART, WIFI, other?

Add any other information that would let me test at similar conditions here.

Title: Re: ESP32-POE-ISO temperature
Post by: Stephane80 on November 11, 2019, 05:09:58 PM
I do not know if it may matter, but it's exactly a ESP32-POE-ISO-EA version

It's my first esp32 from OLIMEX .I just tested before on TTGO esp32 boards but not POE
The borad is powered via POE ( NETGEAR JGS524PE - 24-Port Gigabit Ethernet PoE Smart Managed Plus Switch )


The can module is connected to +3.3 and GND pins
tx and rx connected to pins 4 and 5

I use the ESP32CAN library to get can messages from other devices in my home
The ESP32 send the infos to a Mosquitto MQTT Broker by LAN
For a JEEDOM home Automation
The ESP32 board can serve a json page with infos too

At this time I use just ethernet and can with TX/RX
Fonctions used :
PubSubClient for mqtt
ESPmDNS
HTTPClient
ArduinoJson for json
ESP32CAN for CAN
ArduinoOTA for OTA (Lan) firmware update

otherwise I would have liked to know:
I can use ESP32-POE-ISO-EA without external antenna connected ?
for now I left it but I do not have the use.

And can you tell me what is the normal operating temperature range of the board ?
I could see comments especially on amazon of POE cards that burned
If it is not safe and there are risks I would go to an external poe splitter or 5v alimentation but it was not the goal of a POE board ;-)




 
Title: Re: ESP32-POE-ISO temperature
Post by: LubOlimex on November 12, 2019, 09:26:31 AM
> I could see comments especially on amazon of POE cards that burned

These probably apply for the NON-ISO version - and only when you have both PoE and USB power supplies enabled and connected to the board. The ISO version can't burn in this scenario since the USB and the PoE are galavanically separated.

Edit:

The board should operate between -40 and +85 degrees Celsius and 77 degrees is within the specifications. However, my tests with ESP32-POE-ISO boards went up to 55 degrees Celsius for the same part of the board. I added an expansion board on the UEXT and some Ethernet examples but still this part remained around 55 degrees. I currently have no clear idea what might be causing the higher temperature at your side.

Edit2:

The voltage regulator F0505S-2WR3 should work up to 105 degrees Celsius
Title: Re: ESP32-POE-ISO temperature
Post by: Stephane80 on November 12, 2019, 01:54:02 PM
Quote from: LubOlimex on November 12, 2019, 09:26:31 AM> I could see comments especially on amazon of POE cards that burned

These probably apply for the NON-ISO version - and only when you have both PoE and USB power supplies enabled and connected to the board. The ISO version can't burn in this scenario since the USB and the PoE are galavanically separated.
It's on product
ESP32-POE-ISO Board for Espressif ESP32 with Wired 100MBit Ethernet with POE isolation https://www.amazon.fr/dp/B07R1ZMSG7/

Comment:
QuoteGreat idea, POE not usable.
So first of all these are a fantastic idea for combining the power of the ESP32 with the simplicity of wired Ethernet. I build devices for family and just plugging in a cable is so much easier for them than configuring wifi. Plus points: 1) The ethernet worked right out of the box using the Olimex sample. The ETH library is compatible with the wifi library so I didn't need to change any client or webserver code. 2) Has the circuitry to program without pressing buttons which is a pain with most of the ESP32 boards. So why only two stars: 1) The first one I received worked beautifully connected by USB for programming and connected by a non-POE Ethernet. Seemed like this was a winner. However when I plugged in an IIC oled it would not program. Same oled does not interfere with a nano. Having to disconnect the oled to reprogram is worse than pressing a button. The replacement unit has the same programming issue - i.e. can't program with the oled attached. I implemented a web updated, problem solved. 2) When I plugged into POE for power, with only a 20ma oled connected it overheated. I plugged it in and checked the website on it and within a minute or so it died. I picked up the board and burnt my finger. The area that was hot was around the 3.3v regulator and coil, not the POE circuit. After this it got hot in seconds even with non-POE Ethernet and USB power; so I'm guessing the POE overloaded something. This is the same POE I'm running cameras and Raspberry Pis on so I am confident in the POE switch. Returned it. The replacement also gets hot around the POE, where the two 220ohm resistors are. These I think is to provide the necessary 250mw minimum to enable POE, if so they need heatsinks. On the replacement unit, when powered by usb the 3.3v regulator is cold. I tried POE for a few seconds and it started getting noticeably warmer on the 3.3v regulator and so did the 5v DC-DC converter and aforementioned resistors. This was with nothing attached. I'm now using an external POE splitter to provide power to the USB; this works well and everything is staying cool. 3) LIPO charger/power - verified that if you lose power, the unit switched to LIPO and carries on without interruption - great. However when you reconnect USB power it reboots. Fortunately this works for me as I only need to detect loss of external power ( thoughtfully provide on GPIO 39)- and save data to SPIFFS. Summary Great idea and i am definitely going to use it, but with an external splitter. Software works out of the box POE is not usable Issues with updating with devices attached but mitigated by web upload. Final thoughts POE need thermal management and isn't easy to squeeze onto a tiny board. Given that external units are around $5 from china I would prefer a straight Ethernet solution.

Quote from: LubOlimex on November 12, 2019, 09:26:31 AMEdit:

The board should operate between -40 and +85 degrees Celsius and 77 degrees is within the specifications. However, my tests with ESP32-POE-ISO boards went up to 55 degrees Celsius for the same part of the board. I added an expansion board on the UEXT and some Ethernet examples but still this part remained around 55 degrees. I currently have no clear idea what might be causing the higher temperature at your side.
If it's OK and in specifications
No problem for me.
It's just to be sure that it's safe ;-)
Title: Re: ESP32-POE-ISO temperature
Post by: LubOlimex on November 12, 2019, 02:27:52 PM
Can you tell me what is written on the DCDC1 part of your board? Is it Mornsun or Tesla and what is the model?
Title: Re: ESP32-POE-ISO temperature
Post by: Stephane80 on November 12, 2019, 07:00:13 PM
this one ?
(https://imgur.com/1c5wRhL.jpg)
GODSEND F0505S-2WR2 ?

Edit :
not found GODSEND but just see this in morsun F0505S-2WR2 datasheet:
QuoteOperatingTemperature : -40 105
Derating when operating temperature up to85°C,(see Fig.2)
Title: Re: ESP32-POE-ISO temperature
Post by: LubOlimex on November 13, 2019, 04:39:36 PM
I wanted to perform more tests with this specific DC-DC and it seems it also behaves better here - 50 degrees Celsius max. Maybe something in the code or the environment is different. If you want me to perform further analysis or comparison please contact me over the support e-mail - support@olimex.com
Title: Re: ESP32-POE-ISO temperature
Post by: Stephane80 on November 13, 2019, 11:56:34 PM
Hello ,, thank you very much for your help.
I will not make you lose more time.
I will continue the tests and if not I will leave on another solution
with external poe splitter

Best regards , Stephane
Title: Re: ESP32-POE-ISO temperature
Post by: Thibaut on May 22, 2020, 12:11:34 AM
Hi,

I have the same issue (GODSEND F0505S-2WR2, 1950)


Nothing connected and just running a small program (collecting BTE beacons to a mqtt queue) the black box heats up to more than 60C when powered over POE (Usb disconnected or connected does not matter), at ambient temperatures, and not even in a case. (EDIT: I now checked again and measured 71.2 C between the black block and the ethernet adapter)

It stays cool only when powered over USB.

I was planning on using the devices in my new house, however I'm not so sure anymore.

@Stephane, what did you do at the end. Did you add a POE to 5V splitter before the device at the end?

@LubOlimex. How hot will the non ISO version get?

Thanks
Title: Re: ESP32-POE-ISO temperature
Post by: LubOlimex on May 22, 2020, 09:03:13 AM
71.2 is not too hot. That is the typical temperature of a video card in your personal computer.

You should start worrying above 85..

Title: Re: ESP32-POE-ISO temperature
Post by: Thibaut on May 22, 2020, 10:45:34 AM
Hi,

Thanks for the quick reply.

But the temperature of the board is already above what is marked as safe to operate on the website:
"ESP32-POE-ISO and ESP32-POE-ISO-EA are with commercial temperature range 0-70C"

How hot will the non ISO version get if I would use that one instead?

Thanks
Title: Re: ESP32-POE-ISO temperature
Post by: LubOlimex on May 22, 2020, 11:38:53 AM
0-70 is ambient temperature range around the board, like the air in the room. Board in commercial temperature range allows you to use it in environments that don't go under 0 degrees C and where it doesn't get hotter than 70 degrees C.

Edit: the ISO version would probably get as hot as the non-ISO version
Title: Re: ESP32-POE-ISO temperature
Post by: Thibaut on May 22, 2020, 11:43:13 AM
Ok, thank you! :)
Title: Re: ESP32-POE-ISO temperature
Post by: Huntercover on January 14, 2022, 10:38:31 PM
Hello Olimex-team,

I would like to answer on that old topic because I feel to have the same problem with a non ISO version:
I bought a non ISO version and from my point of view the board is getting too warm as well.

Question: May I connect USB + ethernet together if I am using an external POE splitter directly before the board? I am asking because I have the non ISO version..
To make it clear:
- I am having one ethernet line from a POE switch
- Using a external POE splitter to get a LAN cable and micro USB.

Will the board burn if I plug the 2 connectors in?

Regards,

Andreas
Title: Re: ESP32-POE-ISO temperature
Post by: LubOlimex on January 21, 2022, 10:26:15 AM
As long as the PoE power does not go into the ESP32-POE board but only the Ethernet connectivity (as in your case since you get the power off before the board) - it should be safe. Just double check what your splitter does exactly.

If you can keep your finger over the components of the board for more than 10 seconds - it is not too hot.
Title: Re: ESP32-POE-ISO temperature
Post by: gender on October 25, 2022, 07:36:45 PM
Hi,
I have exactly the same problem with my ESP32 POE:

If Im only using POE, the microcontroller is very very hot... so hot that I can not keep my finger over the components for more than 10 seconds.



If Im using Ehternet and USB together (without POE) the problem is gone. There is no hot components at all.


So, it is a workarround for me to use USB-Power but actually I would like to use the ESP32 over POE !!!

Is there any solution for the hot components?

The hottest point by the way is at the black thing close to the letters "olmex":(https://www.google.com/search?q=ESP32+POE&client=firefox-b-d&source=lnms&tbm=isch&sa=X&ved=2ahUKEwjfiNSq5_v6AhUjsKQKHVh-DhQQ_AUoAnoECAEQBA&biw=2560&bih=1315&dpr=1#imgrc=V9SznGIb5climM)





Title: Re: ESP32-POE-ISO temperature
Post by: LubOlimex on October 27, 2022, 09:54:00 AM
It is normal to be hot. Voltage from PoE is above 50V that have to be transformed into 3.3V by a tiny piece of electronics... When you power from USB it is 5V that has to be transformed into 3.3V, so naturally it is much easier.
Title: Re: ESP32-POE-ISO temperature
Post by: Drjaymz on November 11, 2022, 11:55:37 AM
Mine is getting too hot.  I'm measuring 50V and looking at the schematic, that is across R41 which is 4k7. At 50V thats over half a watt.

I am not sure why R41 exists.  But I think its one of a host of fudges to attempt to deal with glitching that this board design seems to have been plagued with looking at the revision changes.  I think its there to discharge C27 and soak up any transients.

Half a watt is easily within that resistor's capability, a hot resistor isn't going to fail.  I just put a thermocouple on mind and its 126C - half of that heat is soaking into the ground plane to which one end is soldered.

Unfortunately, because of the layout it heats up C26 and C27 and will cause them to fail and there's a couple of posts of exactly that type of failure and that will happen as soon as you enclose the design.  105c capacitors or not, remember at 105c their life is 1000hrs.

I will remove R41 and measure the temps again and see how long it is before it glitches.
Title: Re: ESP32-POE-ISO temperature
Post by: Drjaymz on November 11, 2022, 01:11:39 PM
Quote from: Drjaymz on November 11, 2022, 11:55:37 AMI will remove R41 and measure the temps again and see how long it is before it glitches.

sitrep, with R41 removed its been up and running and has stabilized at about 35C which is a lot better than 90C and I would consider it ok to use in an enclosure now.

Another 'bug' I found was that the PG pin(6) from U2 should be pulled high.  If not then you might find that nearby transients could shutdown the DC-DC converter.

The DC-DC converter is perfectly fine at 0.5A from a 50V source, but its limitation window is a package temperature of 80C according to the datasheet.  Without R41 heating it up it doesn't get that warm at all, it should be better than 75% efficient in this circuit.
Title: Re: ESP32-POE-ISO temperature
Post by: LubOlimex on November 11, 2022, 04:09:38 PM
R41 is required to maintain power signature (MPS). Refer to:

https://www.ti.com/lit/ds/symlink/tps2376.pdf?ts=1668174991211

What is the PSE equipment in your setup? Is it compliant with IEEE 802.3af (or newer)?

Title: Re: ESP32-POE-ISO temperature
Post by: Drjaymz on November 11, 2022, 05:44:53 PM
It should be between CLASS (pin 2) and VSS?
Its a loading that is applied to the line to program the power delivery.  The specification says that power delivery will continue as longs as the DET is present - thats R28 on your diagram.
But here R41 is continually on the line which is why its cooking.

(https://www.jcross.co.uk/files/iso.PNG)

And yes, with it removed an 802.3af Fortinet PoE is happy to whack 51 Volts up it.
So, with it removed the board consumption drops a lot.  And the environment, the PoE and  and the capacitors can thank  me later.

I get it - you think that 10mA is the minimum load required for MPS?
Title: Re: ESP32-POE-ISO temperature
Post by: Drjaymz on November 11, 2022, 06:19:31 PM
https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/251393/poe---maintain-power-signature

Here Ti Explain that MPS is pulsed and that the chip switches in the CLASS sense when required.

That will be why mine works fine without the parasitic load.

He says:

 I think I see where you confusion may lie. In TPS2375 DS, Table 1 lists class 0 current (in the 802.3af LIMITS (mA) column) as 0-4mA. This current is not the operating current, but is the current that TPS2375 presents to the PSE during classification

To be fair, the actual datasheet is very waffley and suggests that MPS is a minimum load - its not.
Title: Re: ESP32-POE-ISO temperature
Post by: LubOlimex on November 14, 2022, 11:32:55 AM
Your link proves our hardware design was correct!

From your link: "After classification, then 48V is applied and this is when the PD must maintain the 10mA load (see the PD Power (W) column in Table 1)."

Your quote is for the moment before reaching maximum voltage (only between 13V and 21V), and you omitted that second part that clarifies it "In TPS2375 DS, Table 1 lists class 0 current (in the 802.3af LIMITS (mA) column) as 0-4mA. This current is not the operating current, but is the current that TPS2375 presents to the PSE during classification (when the port voltage is between 13V and 21V). "

I don't know how you understand it. It is around 10mA (~47VDC/4.7k).

Furthermore, we used TPS2375EVM's design as a basis and it is connected exactly like that. Check for resistor R11 (controlled by jumper JP7) in schematic on chapter 5-1 in the document here:

https://www.ti.com/lit/ug/slvu108/slvu108.pdf

If it heats for you, you can remove it, but if it heats it is because of your PSE equipment is not made according to the standards, not because our hardware design is bad.
Title: Re: ESP32-POE-ISO temperature
Post by: Drjaymz on November 14, 2022, 05:18:50 PM
QuoteIf it heats for you, you can remove it, but if it heats it is because of your PSE equipment is not made according to the standards, not because our hardware design is bad.

OK, I'll concede if you're going to maintain class zero you'll need >=10mA, although that isn't defined as a DC load (like a resistor), for simple designs it probably is. The evaluation kit you refer to has a parasitic load because it must work standalone without a connected load and that has caught a few people out.  If you have a load connected, then you can remove JP7.  That is basically what the response is saying because none of the reference designs have it.

The resister heats up because its across 50V (I2R losses), regardless of the PSE - you'll always get that heating, don't be blaming the PSE compliance!

Its problematic because the resistor is thermally coupled to ground and heats the everything and it seems a common complaint.  C26 and C27 in particular are not going to like that long term and its not ok to be 90C. But as I said to others its not going to bother a resistor its well within its happy zone.  Mine got to 90C and this room has no heating in it.

But, is it necessary?  Lets have a look at the schematic...

Lets suppose your DC-DC conversion was 80% efficient you'd need to see about 0.4W downstream to ensure a loading of 10mA at 50V.  The ESP32 is nominally about that as it happens, then you have a few other parts like the PoE parts itself etc. In reality, at lower currents the DCDC conversion is more like 65 - 70% as per its datasheet and we don't care about higher loads.

As it happens, experiment is worth a thousand opinions so I measured it - I get 11mA at 51V from the PoE which roughly matches what the PSE says.  And I don't have R41 connected.  So thats why it works.  Another board I have with the resistor still attached measure 20mA which is what you'd expect.

Now, as a board designer, you can't assume that someone will not put the esp32 into sleep mode, but the irony is they won't be saving power.  So thats why you have that load - but I can make a couple of suggestions.

1) thermally isolate R41 from the ground plane better - or use a through hole.
2) provide a jumper just like the eval board - because I think whatever you do it will heat up the board.
Title: Re: ESP32-POE-ISO temperature
Post by: LubOlimex on November 15, 2022, 09:02:07 AM
> But, is it necessary?  Lets have a look at the schematic...

Well, you already answered yourself. Yes. In fact we didn't have this resistor when we switched to TPS2375 and weren't aware of the MPS requirement during sleep. This was causing two issues:

1) It turns out most of the customers use these boards on remote locations where sleep and deep sleep are important to conserve power during power downs. Furthermore, most of the customers evaluating which ESP32 board to consider would always measure power consumption in sleep and deep sleep modes. And the boards in sleep would lose PoE power since the PSE would turn off the power supply completely.

2) Same thing naturally happened when using the on-board reset button.

Of course we would consider your advice for future revisions. I've added notices for future revisions to again empirically measure the load and the temperature and to consider better routing of R41 or/and adding a jumper.

Thanks for your constructive feedback.
Title: Re: ESP32-POE-ISO temperature
Post by: Drjaymz on November 16, 2022, 03:01:29 PM
Quote from: LubOlimex on November 15, 2022, 09:02:07 AM> But, is it necessary?  Lets have a look at the schematic...

Well, you already answered yourself. Yes. In fact we didn't have this resistor when we switched to TPS2375 and weren't aware of the MPS requirement during sleep. This was causing two issues:

1) It turns out most of the customers use these boards on remote locations where sleep and deep sleep are important to conserve power during power downs. Furthermore, most of the customers evaluating which ESP32 board to consider would always measure power consumption in sleep and deep sleep modes. And the boards in sleep would lose PoE power since the PSE would turn off the power supply completely.

2) Same thing naturally happened when using the on-board reset button.

Of course we would consider your advice for future revisions. I've added notices for future revisions to again empirically measure the load and the temperature and to consider better routing of R41 or/and adding a jumper.

Thanks for your constructive feedback.

I hadn't considered the consumption drop on using the reset button.  I tried it and it seemed ok.  But some PSE may be more finicky.  I only have a fortiswitch and tplink brands and they don't drop the power until a few seconds after you remove it and provided you pull >10mA at any point in the last second or so they are happy.

The irony is that the MPS resistor is wasting as much power as they are saving.  And its not OK anymore to burn 1W for nothing, especially if we have 1000 of these out there.  It will be an improvement if the ESP32 is enough for most PSE's.

In a way the board is perhaps a little too efficient, there is a 3v3 switched where most would use a linear reg, great for battery operation.  Luckily the 5V DCDC isn't too efficient
Title: Re: ESP32-POE-ISO temperature
Post by: Konsulten on March 29, 2023, 09:03:43 PM
Hi is this valid also for the non ISO version. That R41(R42 on non iso) can be removed so the board no longer heats up as high?
I burnt and browned a plastic casing that was with good ventilation. And later found this post.

Title: Re: ESP32-POE-ISO temperature
Post by: LubOlimex on March 30, 2023, 08:24:49 AM
Yes, removing R41 will lower heat but still notice what I described previously and consider that your PoE switch might disconnect the board. Probably you can test it empirically, remove R41 and test for a few days to see if that causes disconnects from the switch. If it does, solder R41 back. Notice that the expected behavior largely depends on the PoE equipment. If you expect your project to connect to different switches, it is better idea to keep R41.

You can find more about why this resistor is placed if you Google for "Maintain power signature PoE". This is one of the better sources that describes it:

https://www.poepower.net/mps.html
Title: Re: ESP32-POE-ISO temperature
Post by: Konsulten on March 30, 2023, 10:59:49 AM
Okay. I now noticed that sy8089 step down had been burnt. Could this overheating have caused this? 3.3V is gone from the board and it does not power the esp32 anymore. Also I found this board did not look like the other Rev K boards. The C25 was distanced from the board with some rubber thingy. This was not on the other 5 boards I ordered at the same time. Maybe a patched version happened to tag along?

Verified on the other boards that removing R41 indeed lowered the temperature alot and also worked fine with my two different Unifi PoE switches.
Title: Re: ESP32-POE-ISO temperature
Post by: LubOlimex on March 30, 2023, 01:47:27 PM
Without SY8089 you can't power the board...

> The C25 was distanced from the board with some rubber thingy.

Sounds like C25 exploded which is pretty serious hardware fault. It is possible  Did you have USB cable and PoE power attached and enabled at the same time?

You need to at least replace C25, and SY8089 and double and triple check for short circuits on 3.3V and 5V lines before trying to power the board. Even then it is possible that the PoE chips were damaged...

> Verified on the other boards that removing R41 indeed lowered the temperature alot and also worked fine with my two different Unifi PoE switches.

It will work fine until sleep or deep sleep are used. If you don't need sleep or deep sleep it would be fine.
Title: Re: ESP32-POE-ISO temperature
Post by: Konsulten on March 31, 2023, 12:04:40 AM
No I did not have it connected to both PoE and microUsb. It has been running a couple weeks with BLE discovery with PoE until it just died. I dont think the capacitor exploaded. I would say this board was not made in the same way as the other 5 I had ordered. Here is an image of the two different boards. One with the elevated capacitor.
Do you know why this was done?
(https://gcdnb.pbrd.co/images/QgENG5LNfhnP.jpg?o=1)

Is there some warranty for these? Bought in 2022-11-21
Title: Re: ESP32-POE-ISO temperature
Post by: LubOlimex on March 31, 2023, 08:29:27 AM
The board from top image clearly has the capacitor damaged. The board was not made this way definately. It also didn't leave our facilities this way since it will never pass optical inspection tests, let alone empirical tests.

What happened is that the 5V line received more than 5V for some reason. I expect that it won't be just that capacitor but also converters around it, since it is pretty important capacitor that is in the middle of the schematic.

You said you didn't have USB attached at the same time as PoE which is good but:

1) did you have any other device connected to the board at the time of the accident;

2) how did you power it at the time of accident?

We have warranty on all products, but it won't apply here. You didn't receive this board this way, something damaged it. Whether it is overvoltage, static electricity, short circuit contact at the bottom, some other influence in the setup might be hard to determine (but it is important to determine what caused it since it will probably happen again) - the board got damaged. You can find our warranty and returns policy for a reference here:

https://www.olimex.com/wiki/GTC#Warranty
Title: Re: ESP32-POE-ISO temperature
Post by: Konsulten on March 31, 2023, 05:32:15 PM
No other devices. Was used for espresense project. Only PoE from ubiquiti unifi switch.

Yep the cap had been popped
Will check the running time of the device and see if its close to the 1000hours of lifetime of the capacitor
Title: Re: ESP32-POE-ISO temperature
Post by: arumi88 on October 03, 2023, 01:34:48 PM
I found a solution to the ESP32-POE-ISO's heat generation.
- Removed R41
- Add 100ohm/0.25W resistor between +3.3V and GND
This allows heat generation up to nearly 80°C to be suppressed to less than 40°C, and also supports PoE's minimum load of 0.1W.
However, it will affect the operating time of LiPo batteries.
Title: Re: ESP32-POE-ISO temperature
Post by: LubOlimex on October 04, 2023, 09:07:12 AM
> - Add 100ohm/0.25W resistor between +3.3V and GND

Just remove that resistor. It doesn't do anything related to the MPS requirement. It doesn't solve any issue and only bugs the 3.3V circuit. The TPS2376D would still disconnect even if that 100ohm/0.25W is present since the +3.3V is after the TPS2376D.
Title: Re: ESP32-POE-ISO temperature
Post by: mihaiadrian on October 04, 2023, 09:18:51 AM
I am sure that instead of 100Ohm resistor, you might have other power consumer that can do job instead without wasting energy. For example, the Olimex 2.8 display with backlight off, pulls 0.1w .   For now , regarding power consumption without R41 I only have the data here, I need to do some more tests with deep sleep:   https://www.olimex.com/forum/index.php?topic=7993.msg38392#msg38392

I have to say I don;t understand "The TPS2376D would still disconnect even if that 100ohm/0.25W is present since the +3.3V is after the TPS2376D "  -   I would expect that a power consumption of at least 0.5 - 1w either on 5v or on 3v to do the job in keeping power on

My only tests with removed R41, was to keep the board powered for a few hours with ping continuously from another host. No packet was lost. 
Title: Re: ESP32-POE-ISO temperature
Post by: LubOlimex on October 04, 2023, 11:19:33 AM
In normal operation it won't disconnect, it happens only when you are using some low power modes of operation. Hence my advice is to first empirically test or measure the behavior without anything additional (just without the resistor that heats up) and only try additional measures or adding loads and stuff only if it disconnects.
Title: Re: ESP32-POE-ISO temperature
Post by: redbarn1315 on March 15, 2024, 10:07:13 PM
Sorry for resurrecting this topic from the grave but I've also noticed this issue and I would love to see a jumper added if possible that comes installed by default which connects R41 to ground. This would make isolating R41 much easier for projects where MPS using R41 is not required.
Title: Re: ESP32-POE-ISO temperature
Post by: LubOlimex on March 18, 2024, 08:50:29 AM
Thanks for suggestion but there is no place for PTH jumper and if we place SMT jumper it would be similar soldering effort as to remove the resistor. We would consider it for future revisions tho.