Power bank injector for PMP450SM

Hello everybody.

I'm looking for a portable power bank to feed the device in some situations where isn't possible to have 220V. I think this device needs an "active poe" to works; I tryed with a normal powerbank (with passive poe) but doesn't work (with other devices ex Mikrotik works fine).

Do you know where can I find, if it exists ?

Thanks in advance.

Are you using PMP450 or PMP450i? The 450i uses 802.3at PoE, which would allow you to use something like the Veracity PointSource Plus. I haven't tested it myself but it should work fine


If you are using PMP450, you could add a Tycon Power Convertor inline that converts 802.3at back down to the 30VDC required for those, need to confirm the pinout though for that model to select the correct one.

Hi Hux, thx for your reply.

Really I don't know wich model is. On the device is written MODEL NO: C054045C009B.  Close to RJ45 socket I can read: ETHERNET 24 TO 30V 500mA  CAUTION Class2 or LPS


Looks like the 450SM - not the 450i.

I've come up with an option for you that may work though. Tycon Power have a USB to 24V Passive PoE injector. It uses two USB ports to provide 12W of PoE on 5-6 + and 7-8 - @ 24VDC.

The 450SM requires the voltage reversed on those pins though, so you would also need the Tycon power cord to swap this. This ensures power is on 7-8 and negative on 5-6.

Then you could use any good USB powerbank with dual USB charging ports to power an SM. Should be a nice little setup, easy enough to get up towers etc.



Hi Hux, tnx again. So it seems the question is only the polarity of supply. So, to avoid using a lot of devices ( I fix those radios for a local isp an often I works on the roofs), could I using a symply power bank 24Vdc poe injector and the xcross cable you mentioned?

If you use a Smartbank POE like we do, you can make a cable that changes the pins to match Cambium.

Ubiquiti POE: 4, 5 are + , 7,8 are - or return

Cambium POE: 7,8 are +, 4, 5 are - or return

Make a cable that is T568B on one side and then on the other swap 4, 5 and 7, 8 or Blue and White Blue with Brown and White Brown.

Dear Calebvbi

I have a Force 190 and Force 180 in which I want to use Power bank to power them ON incase the National Power Grid goes off.

A typical example is I have a customer who uses the internet at home but anytime the National Power Grid goes off then the radio and POE goes off. But the customer wants a device like a power bank that can still power on the radio and POE(Force190 or Force180) such that there wont be any power interruption if the National Grid goes off. Apart from a UPS or Inverter what else can be used to power on the radio and POE.

Direct 24v DC power (up to 30v, will run down to 10v) can be provided to pins 4/5 & 7/8.
This will power all epmp SMs and the e1k, e2k and e3kL APs. Follow the polarity on the included PSU to ensure you dont have issues with an early model radio that doesnt support agnostic polarity.

If you have a power supply from an old Canopy radio, then cut the brick off and place positive on the wire with the white stripe and connect as per the label. This power injector also can be used to power the e3k AP if given more than 37v and less than 58v, same polarity. I use this and a variable buck/boost converter to set the voltage based on what is to be connected and power off a 7ah SLA.

For customer side power issues, we get them to buy a certified UPS with as large of VA rating as their budget allows, this will keep the radio and the wifi running for a long time and you wont run into legal issues

Warning: you do this at your own risk and I will not be held liable for any damages that result from the following. It is up to you to either have the skills or have someone with the skills and the regulatory body of your area for any device you provide or sell to a client.

If you want to build an option, get a 24v dc 350w power supply, a 1n4001 diode, a fuse holder with 10a fuse a passive power injector that only puts power on pins 4/5 & 7/8, and two 12v SLA batteries at least 7ah but you can go as big as 20ah with increased recovery period. Set power supply no load voltage to 28.6, connect the diode to the positive output of the power supply, and test that you still have voltage, if not reverse the diode. Connect the fuse holder to the battery positive and to the diode, not the power supply (this is very important), connect the battery negative to the power supply negative, wire the batteries in series to get 24v. Connect your passive power injector to the diode/fuse connection and the battery negative so that you get the correct polarity at pins 4/5 & 7/8. Use the included Cambium PSU label to reference.
If you place this inside a nice enclosure then remember to lable the powered port as “To Radio” to ensure accidents dont happen.
A 7ah battery at 24v will last over 14hrs but takes close to 30 to fully recharge. A 20ah battery will last over 30hrs but requires more than 48hrs to recharge fully. Expected battery life is 300 to 400 cycles, less if the battery is allowed to run completely dead.
If you need to provide another voltage (say 12v or 9v) for wifi router power, then use a buck converter to supply the stabilized voltage from 24v, do not tap off one battery or you will have troubles. Remember to add fuses for each output, the f180/f200/f300 radios need 2A max, most routers need 1 to 1.5A. Automotive fuses on 24v and less is acceptable and preferred as they are designed to operate at these voltages and will open near the correct ratings.

This is essentially what we power our towers like with some key differences such as use of Packetflux’s sync injectors and much larger power supplies and batteries (we use 500ah flooded for most applications with a couple lithium setups in long term testing). We also have the qualified people to design, build and care for these systems. We also have insurance to cover our built to purpose systems under our direct control and operation. So I encourage you to convince your customers to use readily available UPS’s with at least 1500VA or more. Considering the expected loads this will give plenty of operating time. If they need more than a few hours, then they should be using a backup generator and the UPS would be a carryover device to give the generator time to start and supply power. For these kinds of needs, work with a couple electrical contractors to provide these value added services and let the customer decide.