Not good, they will be drawing at least 40 watts of power each even when idling. Do your sums as moving to ARM based boards can save you the purchase price in less than 2 years in some cases.
The other issue if your using a POE switch is you will be creating HEAT in a single unit that will need to be cooled. Consider where this will be, can a cupboard your using now handle the heat? Will fan noise be an issue?
Hi @matt1
yes fan noise is an issue on two of them at least, other ones are “servers”
but i will need some kind of cooling anyway , as i am puting them in a wood cabin
at least one of them has some kind of vent out…
I meant your Poe power source will create heat and hence noise that is easy to overlook. If your thinking of doing 400 watts of Poe that is a heater running in your rack that will need cooling. Add a UPS and that’s more heat.
thanks i will pay attention to that also…
i have 250W for now , and i dont have a fan on that switch
its metal and i think passive cooling so noise will not be an issue
but i wonder how effctive is the passive cooling running on full load
Typically, this will be less heat than using multiple converters since (generally speaking) higher loads on an SMPS will deliver higher efficiency. Most of the switches that I’d expect home users to use (unless it’s a big system) are fan-less these days.
That is quite a large system and I’d be surprised if many people get up to that level. My system here has 3 WiFi APs, and 3 other devices, and it’s around 100W max. It’s very unlikely you’re going to be delivering 40W to a single device using PoE 
My system is totally fan-less - PoE switch, APS rack mount UPS, an NUC mini server, 2 Synology NAS boxes, broadband router. This sits next to me in the study and is obviously totally quiet unless there’s a power cut when things start beeping, clicking and humming
I havn´t read the thread on the Rpi forums. But have a coupple of questions.
Did you ever tried if the Rpi survive a power outrage using that power bank.?
How is the power bank connected. Using a USB-C splitter I assume? Would it require a speciel splitter then?
It’s very unlikely you’re going to be delivering 40W to a single device using PoE
Indeed the 802.3at spec maximum is 30 watts.
I LOVE that Freudian slip of a typo.
Hi kim yes it looks like this powerbanks will do the job
but if you ask me to expnsive for a UPS 5V system
You guys should review your aims before committing to costly plans.
If you UPS protect your server and entire network … what’s it going to do? The power’s off, no lights no heat to control. Yay, my occupancy detection still works!
Of course you can make arrangements to protect other vital services, but if you’ve been smart they can work in a fallback mode without server or network anyway.
You certainly can decide to have backup for everything, and centralized solutions are likely to be more cost effective, but do make sure you arrive at those decisions by careful consideration.
A Pi on a power pack might do, if all it really has to look after is a battery door lock.
Thanks… My idea was mainly targeting the loss of data in case there is a shot power failuer.
A “real” UPS is prefered though, but a power bank could come in hard.
I always forget that point, because I’m not from a *nix background.
I remember 40 years ago when little Unix servers were beginning to creep into datacentres, and each had a UPS partner. "Why?’ “Well if they power off it trashes the system.” “??? but why don’t you just manage storage properly, like all these other systems ???”. Never understood.
… and you can switch all your wall tablets and the desk phone’s displays showing a white screen giving you “emergency illumination”. No need searching for candles anymore…
</joke>
As I said before…
EDIT: Just found this - PoE-lights :- 
@rossko57
with all due respect i think you are missing the point here…
there are some devices i rather not go offline… like cheap IR blasters that cant have static IP
or somthing like that… so POE USB power strip will come handy at every place i own a TV\AC\ and IR devices , it will also serve my 5 zigbee sticks also nice not having them offline , same for sonnoff RF Bridge
POE camras… also as a PIR sensor
if my alram will stay alive during a power break it will make me happy
including my DIY smart locks
i think POE is very good at keeping things alive from a central point… that you can UPS (my slang 
dont copy )
all the points for power loss and heat are valid… but if you know what you are doing and you have
allot of POE drops on your house , you can take advetge of the situation each one of us with his own uniqe needs, and drop locations
i did not want to get into all the things POE has to offer becuse this is not the point of topic
yes it can do Lights you can ask @MDAR
who i saw playing with some coool RGB POE lights that can dazy chain
i am sure you can find a battery solution for everything
but i dont like to monitor/change/buy/throw batteries… seems
like hard wire is easier once you setup for the first time
I would also add that even if an OS uses a transactional filesystem that can cope with power outages (and most Linux systems should!), that doesn’t make it a good idea to turn off the power. A proper shutdown allows bindings etc to properly save their state - so even if the filesystem may not be corrupted if power is removed, data WILL be lost, and that is bad news (in my opinion anyway 
).
Arrrrrrrr !!!
i think power breaks and system reboots can cause allot of problems
specially at DIY home… and if POE can take some of the headhece away be my guest
i was not planing to run lights or any havy devices , but USB sticks and SBC are very welcome
there are some cases that dont make sense
for exmaple i was thinking about powering my 5 port switchs(each room has some kind of dumb switch ) from POE but what is the point when you dont have any other device online, that is also conncted to it
That’s not correct.
PoE has a POWER limitation - This is in the 15 to 30W depending on the flavour of the switch you have. This is not the same as current - eg just because a USB device wants 100mA of current, this does not equate to a large load at all on PoE (USB being ~5v where PoE supplies at ~50v). It would easily be possible to run an Intel NUC, with a ZigBee and ZWave dongle off a standard 802.3at source as this is only consuming around 23W.
Power is not measured in mA - power is defined in watts - Current is measured in mA. As I mentioned above, there is a square law between them - ie Power = Current Squared x Resistance.
LAN cable is certainly designed for this since the current is actually reasonably low. Cat-5 cable uses 24AWG which has a current capacity around 600mA from memory. 30W (the limit of PoE) at 50V is approximately 600mA - Cat-6 I think is even more capable from memory (slightly larger wire gauge I think). So, it does work, and it is reasonably capable, and you probably could run lights off it (eg 20W LED lights should be fine) - even if it’s probably not my preference .
Probably you’d be best to use Cat-6 for the higher power loads - if you’re using 802.3af (which is limited to 15W) then Cat-5 should be fine.
That’s fine - 23AWG is thicker than 24AWG so will have a slightly high current capacity - the numbers are reversed so a smaller number is a thicker wire.
That is all that is needed so the OS on the Pi can shut down cleanly.
