Thank you Carl, I’ll give that a try and report back!
I was trying to use this exact same setup for a Meshtastic gateway and I was also experiencing the same behaviour on a PoE switch–buzzing, pulsing LED, etc. I thought the RAK PoE hat was defective. I managed to get it working by using a cheap “dumb PoE injector” from aliexpress. I also tested a Ubiquiti PoE injector and that worked just as well. The smart PoE switches do not work on this RAK device!
I also have a bunch of the feather wing PoE ethernet boards, and those work great on a smart PoE switch, running a very low current MCU (particle xenon nrf52), so I know it’s possible to create a PoE hat that works as it should; and it’s up to RAK to make this product work properly (maybe hire Patrick, link below, to advise them on their circuit)
Confirmed! 25ohm resister did the trick. I didn’t test the 100ohm resister, since this is a PoE build, I’m not too worried about being perfectly efficient on the power draw, so the 25 ohm is fine for me.
I soldered the 25 ohm resister to the connector pigtail I found:
I connected the pigtail with 25 ohm resister to the 5v output of the RAK 19018 and this is the Final build with resistor leads taped up and tucked away:
She powers up and runs perfectly now on my Ubiquiti PoE switch
Thanks for helping me solve this Carl!!
Awesome news @rkneeshaw !
Btw, I am not sure what is the power rating of your resistor but it will dissipate 1W continuously. Maybe at least 2W or even a bit bigger might better for long term outdoor deployment. Anyways, we can see its performance once out there 
Great idea, I did use a 1w resister (not on purpose) and it gets a bit warm. I’m going to switch to a 2w or even a 5w is the same price, will give a little more headroom.
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Hi, sorry for resurrecting this thread but I found a lot of great info there and also it made me think about a possible solution for my problem.
What if I connect PoE, a solar panel and a battery all at the same time? Or, if that’s not advisable, PoE and battery?
No problem to connect all three. battery will be charged through either PoE or solar (most likely through PoE, as it provides a stable 5V).
If PoE is down, powered by battery.
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When using PoE with the RAK19018 module, several users recommend using “dumb” PoE injectors instead of smart ones, which can cause compatibility issues. Some also suggest adding a load resistor to improve power stability and prevent the module from misbehaving. Others found using a battery to provide a more consistent power source helpful
Hi Folks. I’ve got 19001 base board, 13800 ethernet module, and piggy back PoE module 19018.
The power pinout shown above and on the datasheet page below shows the incorrect polarity for the 5v outputs both on the header pins and the 2pin connector…
I verified this by checking the Poe module away from the main board on a meter and mounted to the base board. What’s shows as positive on the pinouts is directly connected to ground of the base board.
It appears to be a datasheet error and connecting actual 5v from the Poe header to the solar positive input works ok. No magic smoke.
Fairly serious documentation error.
Welcome to the forum @Ferrograph
Thank you for reporting the documentation problem.
You actually don’t need any wires. RAK13800 + RAK19018 do directly supply the Base Board without any additional wires.
Thanks for letting me know about not needing the wires. I’ll try without them but it previously didn’t work.
Could be a problem with the PoE injector. There are some posts here in the forum about it.
I am using a TP-Link Ethernet Hub with integrated PoE and have two RAK19007 + RAK4631 + RAk13800 + RAK19018 working without any additional wires.
Hi all
New to the forum. I have a question. I have a Uniifi Switch and of what I read above it’s possible for the switch to supply PoE to my setup but it doesn’t work.
I have RAK19007 + RAK13800 + RAK19018.
Im not really sure what could be going wrong. Have tested the port on the switch and cable and it’s OK but nothing happens with that combination above. I also tried a cable from the connector on the RAK19018 to the solar connector on the 19007. Again nothing.
Any suggestions form anyone?
Try this ==> PoE with RAK19018, how to - #19 by rkneeshaw
It seems to depend on the PoE injector. I am using a tp-link hub with PoE injector with the RAK13800 and it works without any problems.
Thanks I’ll check it out