I have a line-powered (standard AC) device that sinks 50W in steady-state and I need to power it for 10 hours in case of service interruption.
I'm assuming that I can use, say, a 500W UPS (50W * 10hr = 500Whr = 500W * 1hr) to power it for 10 hours.
But where can I find that kind of UPS? Looking at, for example, CyberPower, I see the model I currently own will supply 600W for only 1 minute (if I'm reading the spec correctly here, under product features "Runtime (half/full)." (Actually, I don't know how to read that since it says full = 1 minute, half = 6 minutes, so maybe it isn't linear?)
Anyway, where can I find a battery backed UPS that will supply 50W for 10 hours?
Bonus questions: The UPS specs generally also use VA as units as well as W. Is this due to RMS factors for sine wave power or what? And does it affect my calculations?