This topic has been inspired by this post https://community.plus.net/t5/My-Router/Simple-question-does-Hub2-provide-Power-over-Ethernet-PoE/m-.... Here the OP has stated I've got an 850 VA UPS for the Hub 2. This might be interpreted that the high 850VA output is related to how long the UPS will sustain the Hub 2 and VoIP phone. This is not the case.
There is no direct relationship between the VA rating of a UPS and the time it’s capable of sustaining a load, all we know is that it’s capable of supplying 850VA at 240V ac for an undefined time, it might be seconds, it could just as well be several days.
A UPS can be used for more than one purpose. It can be used to supply, in this example, 850 VA for long enough for a server/computer etc to be shut down in an orderly manner, when the time is measured in seconds. Alternatively, the requirement can be to keep an Internet connection and VoIP phone alive for days.
In this latter case the most significant factor is the Ah capacity of the battery or Wh capacity of the UPS, something not always specified, as in the linked example.
Mains output UPSs are not in my opinion the way to sustain an emergency connection to the Internet. All the components require 12V dc as supplied by the mains power plugs. A mains powered UPS charges an internal battery (probably 12V) and inverts and transforms the 12V dc from the battery back up to 240V ac. During a power cut the inverter section continues working without the battery being charged. The power plugs then reduce the voltage back down to 12V dc to feed the device. This all takes battery power.
You will find further discussion here: https://community.plus.net/t5/Tech-Help-Software-Hardware-etc/UPS-Back-Up-During-a-Power-Cut/m-p/195...
Moderator and Customer
If this helped - select the Thumb
If it fixed it, help others - select 'This Fixed My Problem'
