energy performance on duo v1?

for the big stuff we have a on wheels generator. If I know there's a big storm I turn that off in the first place as expecting it was the highest using product to the backup(still probably a bad idea to let the brick stay on but the device is off). The UPS shows in raidAR that it should have 40 minutes of power but I don't know if that's taking into effect the other devices on the battery backup. I almost bought a slightly bigger one off buy.com but it was 525 vs 425 and that had the expectation that it was going on a computer and listed the time as 14 minutes for that.

Like has been said (I think) I have the nas set to shut off in a backup option so that's what I've planned for in an emergency situation. At least all devices that plug into th back are energy star(soposed to be up to 60% less power usage when ports not in use) minus the nas though has been spoken for above.