Hey all,
Building out my lab, I was going to get a rackmount UPS. The one I'm looking at is a Cyberpower OR1500LCDRM1U. It says it offers:
1500 VA, 900 W, 120 V
Do I understand correctly that all I need to do is find the Wattage rating for each of the components I want to plug in and add them up? My components right now are pretty light, only about 120 watts total. But soon I'm going to expand and build out a Nutanix CE cluster with 3 nodes and a rack of drives. I was looking at using some NUCs but they are each rated at 330W.
So that would mean even the NUCs by themselves would over-provision the UPS right? Then on top of that I would still need all the other equipment in the rack to be powered.
Am I understanding this correctly or is there something I'm missing?
Other have answered the runtime and load question very well already.
I have three other points.
Batteries degrade over time. Over-speccing your UPS means more likelyhood that things will hold up in three years time as the capacity given is for new ones. Plus, not running your UPS at 100% capacity reduces its stress. Again, more reliable.
You can get a much better quality UPS by buying a second hand one without batteries off ebay and replacing them yourself, typically for a fraction of the cost of buying new. Plus you know you have new batteries. UPS is something where quality genuinely matters. I've had to carry a cheap and badly made UPS out of an office whilst it was on fire, so now I spec more carefully. (And ensure they're metal bodied!)
Consider what you NEED to power. What sort of power cuts are you expecting? Does it matter if something goes down?
I UPS my servers and my main desktop, but not my routers, nor my wifi or IOT things. My internet provider also goes out when there's a cut (I'm on a mesh system so rely on neighbours, who will typically also be down) and I can't do much without power anyway, but it keeps the disks spinning. We typically get very short automated outages here of less than 10s (yesterday was a bad day, we had 9 within 2 hours)