by vreihen » Sun Dec 19, 2010 8:15 pm
Keep in mind that unless you are looking at a premium-grade UPS, it is most likely also (1) a modified sine wave, and (2) not double-conversion. If it is not double-conversion (which runs the inverter at all times), the inverter is not going to be happy running at any kind of duty cycle more than the 15 minutes or so it was intended to run your computer for during a power outage.
I have all kinds of APC desktop UPS's at work. Not one of them has a fan or cooling fins, and the latest ones come in plastic cases. Not exactly the recipe for running for hours under load.....