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semaja2
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Joined: Wed Sep 08, 2021 3:50 pm

Rack mount CRS3xx Series Switch with DC input

Wed Nov 10, 2021 3:50 am

Whilst the NetPower16P is based on the CRS328, and provides DC inputs it is really only suitable for mounting on a pole

However there does not appear to be any other CRS3xx series switches that can run directly on DC inputs?

Has anyone modified a CRS328 for DC input, or is this something MikroTik is missing and should add to their products?

Would be great to have an off the shelf PSU that we can swap out and put DC screws where the IEC plug currently is etc
 
ConnyMercier
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Re: Rack mount CRS3xx Series Switch with DC input

Wed Nov 10, 2021 9:51 am

1. Mikrotik CRS3XX with DC-Power Input
The Mikrotik CRS326-24G-2S+RM & CRS326-24G-2S+IN have DC-Inputs
alternatively, use CRS112 or similar...

2. Modification Power-Input
I know someone has modified a CRS3XX for an Offgrid-Application.
You could develope a own solution to ...
-> viewtopic.php?t=179504

3. Modification of NetPower16P
I don't recommend it, but if your likelihood depends on it,
I am sure it is possible to make a Rackmount-Enclosure with cooling
and move the circuit board of NetPower16P to it.


--- Warnings for 2 and 3---
including but not limited to :)
- You will VOID any Mikrotik-Support / Garanties
- Voltage from Batteries, Solar-Panel or Main's can be hazardous
- Any voltage fluctuation may translate to Performace degradation
- Any voltage or power fluctuation may also result in RouterOS crashes or Errors
- Don't forget to provide an adequate Battery Protection Circuit (over-discharge protection)
 
marekm
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Re: Rack mount CRS3xx Series Switch with DC input

Fri Nov 19, 2021 6:08 pm

How to open the Netpower 16P? Has anyone made any pictures of what is inside?
Would it be possible to convert PoE-out to reverse PoE-in?
Other devices with PoE-in either have only 100Mb ports (Netpower 15FR) or few ports and only run SwOS (Netpower Lite 7R).
Nothing happens (no power is drawn) when external PoE power is applied to PoE-out ports, I suspect they have series blocking diodes.
The idea is to add diodes from the transformer center tap to the positive supply input, so PoE-in on any port can power the device (instead of doing nothing).
 
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mkx
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Re: Rack mount CRS3xx Series Switch with DC input

Fri Nov 19, 2021 7:06 pm

An idea for DIY of multi-PoEin: take a number of RBGPOE passive power injectors (they are power extractors as well!) and connect the DC lines (using a diode capable of a few amps on each positive pole to prevent power back-surge). And connect that to normal barel-jack power input. Either use some termo-shrinkable tubes or construct a PCB with multiple DC inputs and single output.
 
marekm
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Re: Rack mount CRS3xx Series Switch with DC input

Fri Nov 19, 2021 7:28 pm

One important thing I didn't mention is that I need many of these devices to work outdoors, so multiple RBGPOE is not an easy solution.
Netpower 16P would be the perfect device if it had the diodes wired to support bi-directional PoE-in/out.
Of course you have to be careful about power limits, especially with more than one port as PoE-out and only one (worst case) powered PoE-in port.
If there was enough space inside, I would also add a small non-isolated 48V to 24V step-down DC/DC converter.
Then the device could accept 48V (PoE-in or DC jack) and offer selectable 24V/48V PoE-out.

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