Hi,
The 28W quoted on the data sheet sounds rather thirsty for these devices. Just wondered if anybody is running these on 802.3at/af and would have some real-life inline power readings from your switches you could share, while they’re running full RF output power?
Just trying to work out a realistic power budget for a site with at least 2 units.
Thanks,
Craig
for remote site power budgets, we use the POE injector output of 60w. No it will not use this but if you plan for it then there is some wiggle room as the radios age and start using more power. For reference 802.3at allows allows for 30w per port and 802.3bt allows for 60w per port.
Thanks for the reply Douglas. Planning for absolute maximum as you suggest is certainly one way to be absolutely sure, but not a luxury I have here. Hence my request for actual in-service power draw as detected by the switch. This may end up being a solar installation so I can’t go throwing around an extra 32W per radio on top of spec sheet.
We have some solar sites and you do not size your solar to your load, you need to size it to the battery bank recovery charge rate and for the expected run time of the battery bank which is determined by total current needs. If you want actual numbers ( which change with throughput load) then you will need to setup a link and pull data through the connection while measuring the current.
Our typical solar site has 1AP and two ptp links using f300L and f300-25 or CSM, a packetflux sync injector and a site monitor. For this we use a 24v 500AH battery bank and 2400w of solar with a east/west split array with each panel its own string (dont place panels in series to get your voltage, just wastes surface area and lowers system supplied current which is needed to rechargethe batteries). It is oversized and runs for 4 days without recharge at 80% load to a 75% depth of discharge.
We are currently planning a new site that will have 4 e3k-AP and three f300L ptp APs. We are looking at 1000AH 24v battery bank and 5kw solar with a micro wind turbine to help keep the battery charged and to keep the average DOD to 50% over a 3 day period. Thankfully here if its not sunny then the wind is blowing and a 1200w micro turbine will keep up and maintain the batteries.
We came to our conclusions based on worst-case power usage and the amount of time needed to ride out bad weather for our area and acceptable recovery rates, 1000AH does not recharge in a 8hr (our shortest solar day, which we can use as we are using dual facing arrays) day but it can recover from 50% in three days of good weather despite the overnight losses which we also offset with the planned turbine.
In short that extra 32w per radio (0.66A@48v) is not a major concern unless you forget to include room for equipment and battery aging.
If you’re like me, you have an existing system and looking at the 400 as a drop in replacement without rebuilding the solar site. I’m a bit disappointed with the power consumption of these radios based on what I see in the spec sheets. Hopefully as the chipsets that Cambium utilizes mature their power consumption will go down for subsequent models.
I don’t have one to test (was hoping to see numbers somewhere on the forums) but Cambium usually has a “Peak” and “Typical” rating, and the difference is usually about 5 watts. Edit: To be clear, I’d love if 28w is a start up load and reality was that they typically run at 10 watts, but I kind of doubt it unless Cambium put in a board heater again like they did with an older model (I think it was the 1000?)
IMO if they can get the ePMP 400 series ax devices down to 10-15 watt territory or better I’ll be pushing to slam them in everywhere.
It would be nice to know the answer to this. I just checked data sheet for ptp550 and it says 30w maximum, but i know for a fact they draw about 10-12 watts as im watching one now - its powered by a Netonix switch which reports power draw per port.
I assume if ptp550 says max draw 30watts and actually uses 10-12, then the F400 stating 28watts maximum will use similar or less than pt550.
It would be awesome if someone could plug one F400 into a switch that reports draw and lets us know.
Thanks
Just what I was looking for - thank you Jacob.
