Disabling PoE power on port 9 due to Power Budget Limit

[LRL]

I've had this WS-12-250-DC switch in place now for a month and half and so far it's been rock solid. I'm still running 1.3.2 and not 1.3.3 but I will upgrade it tonight.

Last night I started getting warning that my AF24 link was dropping and when I looked at the radio it's up-time had been reset. So I logged into the switch and the log indicated: Oct 5 17:10:43 switch[807]: Disabling PoE power on port 2 due to Power Budget Limit (150.0 W) at current input voltage (11.9 Vdc).

This seemed odd so I went back through the log and my voltage graphs. The site has dipped down to 11.1v before and never had an issue, but in the wee hours of the morning on the 5th we dipped to 11.0 and the switch started warning about low voltage. It never powered down my AF until the voltage came back up (weird or what?)

Ever since then it's constantly powering off the lowest power priority port. I've since then changed the lowest port to a not so critical link. It seems like if the wattage used spikes over 150 it acts regardless of the input voltage now. Below is a link to the log.

http://www.lrcsnet.com/wm-ws-12-250-dc.txt

[sirhc]

We will be releasing v1.3.5 "SOON" might as well wait a couple days.

BUT - I would strongly suggest changing this site to 24V then you would have a 250 Watt budget.

The budget drops from 250 watts to 200 watts at < 12V

The budget drops from 200 watts to 150 watts at < 11V


You are right on the edge with your budget.

Yes the switches will run down to 9V but they optimized for 24V battery banks. A 12 Volt site is fine if you are not powering a lot of radios.

My guess is you drop below 12V then you get crammed into 150W budget and then at some point several AP's start transmitting a LOT which increases their power consumption and you start hitting the ceiling of your available power.

[LRL]

I can appreciate that they were designed for 24v banks, but 12v has so many advantages over 24v that I would be hard pressed to chose 24 or 48 over 12.

I believe the real problem here to be the budget limit not being reset.

Oct 5 15:26:43 switch[807]: Disabling PoE power on port 2 due to Power Budget Limit (150.0 W) at current input voltage (13.2 Vdc).

At this voltage there is no reason for a limited budget. We keep the batteries voltage 11 or above, but because of resistance the voltage the switch sees is almost always a little less. We have 2awg wire from the banks to the distribution block right beside the switch and 10awg from the block to the switch and all wire is copper. I don't believe there is much more we can do to mitigate resistance.

Based on the linear current draw 250watts at 11v is 22.72 amps, while we plan to never exceed 150 /11=13.63amps

I assume the reason for the limits is due to the linear current draw?

After reviewing the total power usage graph I can't find anywhere we exceeded 150w. I would assume the power decisions are made on the same voltage polling that makes up the graph? I also don't understand why there is no log entry for disabling PoE while the switch showed the voltage below 11. It just seems strange, the way things are in the log.