Conventional wisdom is you want a converter that goes into current limiting on 
overload, not foldback.  That was why people said to get Mean Well RSD series 
instead of SD which would go into foldback.

 

That assumes your load devices will tolerate a momentary dip in voltage, most 
will, but foldback may be what’s causing the “cycling” he is seeing.

 

From: AF <af-boun...@af.afmug.com> On Behalf Of ch...@wbmfg.com
Sent: Thursday, September 3, 2020 4:07 PM
To: af@af.afmug.com
Subject: Re: [AFMUG] 24v to 48v upconverter pulses

 

I found this problem with every single cheap DC-DC I have used if I buy too 
close to the load I need.  5X or 10X then they are OK.  

 

From: Adam Moffett 

Sent: Thursday, September 3, 2020 1:18 PM

To: af@af.afmug.com <mailto:af@af.afmug.com>  

Subject: Re: [AFMUG] 24v to 48v upconverter pulses

 

This is all true, but how much inrush current can you have with one switch and 
one PoE device?

 

On 9/3/2020 3:15 PM, Chuck McCown wrote:

Yeah a fully charged 24 volt rechargeable battery in parallel with the load 
would probably fix the problem.  Get a couple small gel cells.  But they will 
have an inrush current too.

Sent from my iPhone





On Sep 3, 2020, at 1:11 PM, Ken Hohhof mailto:af...@kwisp.com wrote:

 

I guess I’d like to hear how many watts you need for stuff that can run on 
48/56 volts, vs how many for stuff that must have 24V.

 

240 watts is a lot of 48V, I would seriously think about a 48V power supply and 
battery string.  Even if you put that along side your 24V setup.  Batteries are 
really good at handling inrush current.

 

 

From: AF mailto:af-boun...@af.afmug.com On Behalf Of Chuck McCown
Sent: Thursday, September 3, 2020 1:56 PM
To: AnimalFarm Microwave Users Group mailto:af@af.afmug.com
Subject: Re: [AFMUG] 24v to 48v upconverter pulses

 

Lots of equipment will have a high inrush current wham starting.  I think you 
don’t have enough capacity to get things started.  Cheap DC-DC converters don’t 
like high starting loads.  A fix would be a series inductor with a flywheel 
diode.  I am on the road else I would help with some component selection.

Sent from my iPhone






On Sep 3, 2020, at 11:34 AM, Sterling Jacobson <sterl...@avative.net 
<mailto:sterl...@avative.net> > wrote:

 

I bought a cheap 24v to 48v (5A max) upconvert from Amazon.

 

I have it wired to feed a MT CRS switch via DC and radio via POE on the 48v leg.

 

But when I plug everything in, the CRS doesn’t show any lights, and the 
radio/POE just pulses green light it’s powering, then not powering in a cycle.

 

When I remove the radio POE, the CRS will start pulsing green light it’s 
getting power for a split second, then not, then power, in a cycle just like 
the radio POE.

After maybe 10-20 seconds the CRS finally gets full power and boots up just 
fine.

After it begins to get full power I can plug in the POE to the radio and it 
boots up just fine too.

 

I’ve tried different power supplies and different POE injectors and different 
CRS switches and different 24v to 48v upconvert modules, always the same.

 

So I’m thinking I need to do something inline with the 24v feed to maybe delay 
or build up amperage first?

 

It really sounds like an odd electronics problem with this particular 
upconverter that may be lacking a component necessary for my scenario.

 

What do you electronics people think?

 

From: AF <af-boun...@af.afmug.com <mailto:af-boun...@af.afmug.com> > On Behalf 
Of Josh Baird
Sent: Wednesday, September 2, 2020 6:42 AM
To: AnimalFarm Microwave Users Group <af@af.afmug.com <mailto:af@af.afmug.com> >
Subject: Re: [AFMUG] Mikrotik Vrrp

 

Yes - the VRRP should be a /32.  Typical configuration looks like this:

 

Router1:

 

ether1:  192.168.1.2/24 <http://192.168.1.2/24> 

vrrp.ether1:  192.168.1.1/32 <http://192.168.1.1/32> 

 

Router2:

 

ether1: 192.168.1.3/24 <http://192.168.1.3/24> 

vrrp.ether1:  192.168.1.1/32 <http://192.168.1.1/32> 

 

Your VRRP interface (192.168.1.1/32 <http://192.168.1.1/32> ) should be a /32, 
and it should be on the same subnet as your "physical" interfaces.

 

On Tue, Sep 1, 2020 at 11:06 PM Rhys Cuff (Speedweb Internet) via AF 
<af@af.afmug.com <mailto:af@af.afmug.com> > wrote:

Hi Guys

 

Has anyone had much experience with using Vrrp on a Mikrotik?

It seemed pretty easy to setup but the manual said the floating IP must be a 
/32 and to put an IP on the physical interface with a /24

This seemed wrong so I just put a /24 on the Vrrp interface and a completely 
different subnet on the physical interface for the routers to communicate.

 

Thinking I was clever all was well till about 1am two days after I did this, 
then it completely failed, switching back and forth from master to backup, 
basically having two masters on and off.

 

Is having a /32 on the vrrp really necessary, if so why?

Why would it have been all good for two days?

 

So my config that lasted two days

Vrrp 192.168.1.1/24 <http://192.168.1.1/24>  (floating IP I care about)

Physical 10.0.1.1/24 <http://10.0.1.1/24>   (to communicate with master/backup 
routers)

 

How the manual says to do it

Vrrp 192.168.1.1/32 <http://192.168.1.1/32> 

Physical 192.168.1.2/24 <http://192.168.1.2/24> 

 

Doing it the second way will mean a lot more IP’s/config as I want to have 
around 20 floating IP’s 

 

Thanks again for any help.

 

Rhys

 

 

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