Started by Stephane80, November 10, 2019, 07:52:02 pm
Quote from: LubOlimex on November 12, 2019, 09:26:31 am> I could see comments especially on amazon of POE cards that burnedThese 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.
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.
QuoteOperatingTemperature : -40 105Derating when operating temperature up to85°C,(see Fig.2)