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PoE value for UBNT

Posted: Thu Aug 01, 2019 1:36 am
by Seb65
Hello,


Can you tell me if I'm not mistaken in the PoE configuration for Ubiquiti equipments :

AF-5 => 48VH
AF5XHD => 24VH

Rocket M5 Titanium => 48V


PBE-5AC-ISO-Gen2 => 24V
PBE-M5-400 => 24V
RP-5AC-Gen2 => 24V

Thanks :thumbsup:

Re: PoE value for UBNT

Posted: Thu Aug 01, 2019 1:59 pm
by sirhc
Seb65 wrote:Hello,


Can you tell me if I'm not mistaken in the PoE configuration for Ubiquiti equipments :

AF-5 => 48VH - And AF24 abd AF24HD
AF5XHD => 24VH - I WOULD USE 48V or 48VH

Rocket M5 Titanium => 48V - YES


PBE-5AC-ISO-Gen2 => 24V - YES
PBE-M5-400 => 24V - YES
RP-5AC-Gen2 => 24V - YES

Thanks :thumbsup:


READ THIS POST
In fact you should read all announcement posts and even sticky posts which are located at top of forums.
https://forum.netonix.com/viewtopic.php?f=6&t=1215#p9040

Re: PoE value for UBNT

Posted: Thu Aug 01, 2019 3:01 pm
by Seb65
AF5XHD => 24VH - I WOULD USE 48V or 48VH

On the datasheet it is indicated PoE injector 24V 1A Passive Power and (2) Full range depends on Ethernet cable length for +18 to +54VDC.

I do not understand why it is necessary to use 48V or 48VH? Should the 48V be used when there is a long cable length?

Re: PoE value for UBNT

Posted: Thu Aug 01, 2019 5:08 pm
by sirhc
Seb65 wrote:
AF5XHD => 24VH - I WOULD USE 48V or 48VH

On the datasheet it is indicated PoE injector 24V 1A Passive Power and (2) Full range depends on Ethernet cable length for +18 to +54VDC.

I do not understand why it is necessary to use 48V or 48VH? Should the 48V be used when there is a long cable length?


It is always better to use higher voltage when possible as it keeps amperage down.

You do understand how amperage is calculated?

watts / volts = Amps

So if the radio uses 12 watts:
    12 watts / 24 volts = .5 amps
    12 watts / 48 volts = .25 amps

Not only that but the switches have on board down converter power supplies to create 24V whereas 48V is passed directly from main power supply.

WS-12-250-AC has 250 watt main power supply but only 160+/- watt 24V power supply and it has to down convert which creates a loss and uses more amperage.

Re: PoE value for UBNT

Posted: Sat Aug 03, 2019 3:02 am
by Seb65
Hello sirhc,

Thanks for the explanation I understand better now!
On my site I have an WS-12-250-AC.

According to you, it is better to use 48V or 48VH? I do not know how to choose ... Câble length AF5XHD-Netonix is 20M.

Re: PoE value for UBNT

Posted: Sat Aug 03, 2019 9:15 am
by sirhc
If a device supports POE power on all 4 pair it is always better to use VH but NEVER use VH if a device is not designed to accept POE power on all 4 pair.

For example if you use 24VH with any 24V airMAX radio you will fry the radio and the switch port and possibly the entire switch.

All this can be figured out with posts we have spent a lot of time putting up here.

Again read all the ANNOUNCEMENT posts under each Forum and probably the Sticky posts.

Like these:
https://forum.netonix.com/viewtopic.php?f=6&t=1178#p8809
https://forum.netonix.com/viewtopic.php?f=6&t=5575#p29908
https://forum.netonix.com/viewtopic.php?f=6&t=1215#p9040