A:Answer Advertised run time at full load is 3 minutes; at half load, 11 minutes. Now this unit has a nominal 1500VA rating, but it's only good for 900 watts full load (per CyberPower site). Your PS is rated at 1000 watts, but it's almost certainly not fully loaded. I'd say 3 minutes is a very safe time to shut down and anything beyond 6 minutes is pushing things. You could easily be good for 8+ minutes when the UPS is new, but that would fall off over time. All UPS run times are guesses after a few weeks in service, so I'm going pretty conservative here. Putting a meter on your system power line (a small Kill-A-Watt meter is about $25) could refine your actual power draw, but even that will vary, depending on what you're doing. A precise UPS runtime number will be precisely wrong.