Greetings, all.
Does anyone here have experience with UPSes powering small loads for long run-times? I notice that almost all marketing materials list run-time "with a PC" (usually in minutes), not mentioning what power rating they assume the PC to be, and avoid listing how much energy the UPS can actually deliver, at least on average (they list battery's V and Ah, but I expect there to be some losses on the inverter, etc.)

I'm looking into putting my small home server (Atom N270) and some network hardware, on it. The total load is 30-35W at most. However, I'm looking into powering this load for at least 2 hours, and have enough energy left for running the 5 W network terminal and the server in S3 sleep state (1W) for at least another 4 hours. I'd be grateful if someone can give me a hint how much VA (or other marketing BS) I need to get the 80 or so Wh I need to have at disposal.

Looking through the web and old topics in this forum, I get the idea that NUT is the software to go for when it comes to UPS and EATON is the brand of choice for supporting the project. Either way, I think all I'll need from the UPS is an immediate notification of power outage, without the PC polling it constantly or taking too much CPU power.

Any hints, recommendations, etc?