UPS Calculation

swinnie · 26 Oct 2015 at 19:52

I have been asked to supply a UPS for a an old Dell PowerEdge T300.

On the sticker, it has:

V: 100 - 240V
A: 8.0 - 4.5A

So, that makes it a 1080W PSU. With UPS Ratings in VA, which does not equal W I'm going to need a pretty hefty UPS? Or are these figures assuming the server is under full load?

Xez · 26 Oct 2015 at 21:33

I highly doubt that a T300 has a 1000w+ PSU, maybe combined if it has two power supplies. Happy to be proved wrong though!

I would typically expect a server like this if it has one processor and not too many hard disks to consume no more than 300w at idle and probably even less.

What is the aim for the UPS? Do you want it purely to safely shut the server down or do you want it to be powered on for as long as possible?

Depending on the hardware specs and what software it is running I'd expect even a APC Smart UPS 750 to be adequate. If it's for a business environment and running SBS with Exchange they can take a while to shut down and it may be wise to go for something a little larger but not massively so.

nutcase · 27 Oct 2015 at 08:26

Does whatever the Dell equivalent of iLO is have a power meter? That should give you an idea of what is needs.

JonnyT · 27 Oct 2015 at 17:40

This should help you out:

http://www.apc.com/tools/ups_selector/

Vince · 30 Oct 2015 at 13:12

I have a spreadsheet for this that was used to spec my new comms room if you are interested. Put in details for any number of devices and it will work out total power draw and circuit sizing.