On Mikrotik devices that have the “Wall-Wart” DC input, as well as PoE, does having both serve as a true redundant power supply?
For instance, if I had a PoE power and the standard AC/DC power adapter connected to the RouterBoard device, and one of the power sources failed, would the RouterBoard continue, uninterrupted?
Hello,
I believe it will continue.
My understanding is that the router will use the higher voltage supply first.
That being the case, it might be better to see if you can use, say an 18V supply for the backup and a 24V supply as the main.
If they are both 24V, then there could be a possibility of flapping?
As @davorjs suggests, the power is drained from the source with higher voltage, but there will be no “flapping” in terms of service interruption even if the voltage of one of the sources drifts, as both the sources seem to feed the same DC-DC converter via a diode matrix. Never seen a scheme but tested that multiple times.