I have a power supply for each mikrotik device at the AP’s, was thinking I could power some, say 4 units from one large power supply but am worried about the obvious if the power supply fails, then by that example 4 units are down, So I am looking for dual power supplies if one section fails then the other takes over, Is there one available at a cost effective price.
n21roadie
something like this?
Thanks , but the item has a bad review by previous customers ?
ive never used any of these, just figured that if servers are including them you could buy them separately. You could probably get a good one from a supermicro chassis (used) even.
If you use a charge controller and run off battery you could use one of these (see link below) to sense the primary supply, when it is no longer available it can toggle a relay which switches over to the secondary supply, when the it senses the primary it will switch back automatically. You have to have a battery system to provide power during the sense and switch over.
This also allows you to use whatever supply you wish.
Hi,
look at this http://www.restlesspowerbox.com
you can use RPB Compact for 4 Routers
If any questions contact me ks (at) cn24.net
Sonny
Just stick two simple power supplies in paralel and connect PSU positive output via diode and you have redundant feature.
Thanks for replies,
The restlesspowerbox features are impressive but I did not read the most important requirement that is redundant power supplies, If the power supply goes down you lose all the devices that were powered from that unit?,
The WebRelay looks promising,
Ideally I suppose I am looking for a:
(1) “hold-off” voltage from power supply 1 to changeover relay circuit, when power supply 1 is missing (i.e.: power supply one failure) the second power supply is used. ( This circuit will be powered from UPS so operation will take place)
(2) Current limit on output supply channels for each device rather than loop the voltage from device to device,(i.e.: power supply feeds 4 (+ 1) AP’s A,B,C.D,E standby AP - if say AP A fails and shorts out power supply, the current limit for channel 1 is activated and power remains on to the remaining AP’s B,C,D,E
(3) I was considering using any surplus Mikrotik device powered from supply 1, and when it loses power the Dude notifies of this event.
Not sure about the stability of attaching a diode on the + of each power supply, I have seen diodes go short circuit as opposed to the popular open circuit fault condition? However thanks for the suggestion
n21roadie
If you not exceed Absolute Maximum Ratings it’s very stable. Regading ralay devices all this devices have bad MTBF rate. And I am not use it for any serious application.
This is good news, can i ask have you have tried this method and works for you, thanks
n21roadie
Since I cange all my 18V PSU to 24V I don’t feel requirement for redundant power supply solution :))
You say changed power supply from 18v to 24v, Are you now running all of your devices from one single 24v power supply,
or have you a 24v power supply for each device,
n21roadie
Has anybody tried this power supply redundancy method?
Hi why dont try a Restlesspowerbox?
You will love it, by its multiple features. And its from only 189 Euro.
You do not need second powesupply, because if the powersupply will fail the integrated batteries will power the router.
you will be informed about a failure by email and/or SMS (optional).
Give it a try!
sonny
http://www.citynetz24.de - http://www.retlesspowerbox.com
How many POE ports does it have and can i attach my 113AH deep cycle battery to this unit for time extension when running on a battery
http://www.amazon.com/Altronix-SMP5-Power-Supply-Charger/dp/B0006ZF4CS
Hooks straight up to your battery and has a built in charge controller.
use 2x and figure out how to wire redundancy…
i think we have a few of these exact ones powering wireless camera gear thats been in service for over 6 years…
how often do you plan on servicing it? 
It has 4 POE ports. If you use 24V battery you can power the box with it.
If the battery is discharging you can Monitor this and get informed by Email.
How are you charging your battery?
I spent 30 years in electronics before wireless networking and this method does work. In this application, the diodes are called “steering diodes”. It allows power to flow from each power supply through a diode to a common positive point to feed the load. If one power supply short-circuits, the diodes prevent power from the remaining good supply from flowing backwards and shorting through the failed supply.
If the load side short-circuits, there isn’t much you can do, it will drag down both power supplies.
I spent 30 years in electronics before wireless networking and this method does work. In this application, the diodes are called “steering diodes”. It allows power to flow from each power supply through a diode to a common positive point to feed the load. If one power supply short-circuits, the diodes prevent power from the remaining good supply from flowing backwards and shorting through the failed supply.
If the load side short-circuits, there isn’t much you can do, it will drag down both power supplies.
My plan is to use a inline fuse for each connected device, so if 8 devices connected and say load no 2 goes short it blows the inline fuse. and prehaps a led light on the load side of the fuse so this will indicate which fuse is gone
It has 4 POE ports. If you use 24V battery you can power the box with it.
If the battery is discharging you can Monitor this and get informed by Email.
How are you charging your battery?
At present i have this battery attached to a UPS in place of the 2 batteries which came with UPS