DC options on WS-6-MINI

qwerty
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DC options on WS-6-MINI

Sun Jul 19, 2020 5:44 pm

We use the ws-6-mini at tower sites because of their small footprint. We have these powered through the barrel connector off a 48v battery pack. It would be a real bonus to have the DC features enabled, to allow us the shut down based on DC voltage, which the switch already reads out. Perhaps this could be looked at as part of a future firmware upgrade. Thx.

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sirhc
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Re: DC options on WS-6-MINI

Tue Jul 28, 2020 2:05 pm

That would require hardware that is not present in the unit.

When I say that I mean the switch powers down and then back up when power is at required levels. That type of hardware is in the WS-8-150-DC and WS-12-250-DC. The WS-12-250-DC being more advanced than the WS-8-150-DC when it come to powering down and back up.

As far as shutting off ports POE based on input voltage that could be done in firmware but then again this is why we have the WS-8-150-DC and WS-12-250-DC. NOw the unit I "think" does shut off 48V POE if voltage is too low but 24V POE works down to about 27-30V input but again this was not designed to operate like this.

The WS-6 was not designed for this type of application, in fact it was not even designed to be powered from batteries but rather a constant 48-54V power supply.
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JustJoe
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Re: DC options on WS-6-MINI

Wed Jul 29, 2020 5:04 am

I don't think this response considered the full perspective. Just because WS-8-150-DC and WS-12-250-DC can boost the last 9VDC gasp of a 48V battery bank input up to 48V is not something you will get away with more than twice before even new batteries become worthless.

Call it what you want, climate in the last ten years has been continually changing. The best designed of solar charged battery banks, using industry "expected solar hours per day" go out the window when you suddenly get 3 solid weeks of heavy cloud overcast in the middle of December.

I think what the OP is suggesting is that an operator might decide it is in everyone's best interest to automatically shut down individual user defined POE tiers of less critical links at remote, difficult to access sites when sunlight unexpectedly misbehaves. Better than hauling in a ton of new batteries through mudslides or snow banks.

Given that perspective, to me it sounded like a reasonable suggestion.

qwerty
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Re: DC options on WS-6-MINI

Thu Jul 30, 2020 9:25 pm

The original intent for this request is to prevent damage to batteries and radios during events where our charging rate can’t keep up. I understand the ws-6 doesn’t have a DC-DC to shut down and start up, like the more advanced models. Nonetheless, this is an important feature for many, and it doesn’t need to be complicated. This would be a volts value, per port, to turn off POE and turn on.

The user would choose the volts based on the equipment to shut down and the value to turn back on. This would reduce the dependence on external components (LVD), and would allow for sequential load shedding. No hardware modification required.

This could allow us to keep the backhaul radios on while turning off the PtMP APs at the site, up to a threshold where we have to turn off the back haul. There would be a continued draw from the switch itself, and I’d plan for that.

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JustJoe
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Re: DC options on WS-6-MINI

Sat Aug 01, 2020 4:33 pm

qwerty wrote:The original intent for this request is to prevent damage to batteries and radios during events where our charging rate can’t keep up. I understand the ws-6 doesn’t have a DC-DC to shut down and start up, like the more advanced models. Nonetheless, this is an important feature for many, and it doesn’t need to be complicated. This would be a volts value, per port, to turn off POE and turn on.

The user would choose the volts based on the equipment to shut down and the value to turn back on. This would reduce the dependence on external components (LVD), and would allow for sequential load shedding. No hardware modification required.

This could allow us to keep the backhaul radios on while turning off the PtMP APs at the site, up to a threshold where we have to turn off the back haul. There would be a continued draw from the switch itself, and I’d plan for that.


I completely support your suggestion. Especially that the user needs to be able to choose those voltages since they may have chosen either a 12, 24, 36, or 48 battery system voltage.

Just as a note, with lead-acid batteries as an example, the turn-off voltage should probably be between some multiple of 11.5-12.0V. But the one thing that gets tricky for a user to program is the turn-on voltage needs to account for a small degree of apparent voltage recovery on the battery bank when any of the POE load is reduced. The internal series resistance of the batteries is what exaggerates that effect. If the turn-on voltage is too close, you can end up creating a high-current oscillator! ;)

qwerty
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Re: DC options on WS-6-MINI

Tue Aug 04, 2020 6:56 pm

Stephen, if there is any chance to add this to a future release, let us know. We would be excited to see this feature in the WS-6-Mini, as we like this unit because of its small footprint and fanless design. Only thing missing for us is this POE port voltage startup/shutdown.

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