I was just reading around and saw sone site that said you shouldn't use these on the power supply, and I was wondering why... I have an inverter in my jeep I've connected my laptop to a couple times because it doesn't run off batteries(I was cheap and got one that doesn't have a battery period, but that's beside the point) Anyway, it works fine, but there is a little buzz from the power supply. Same goes for my UPS. It causes my power supply to buzz a little bit.
I check both with a volton meter... The UPS puts out around 95 volts, and the interter in my jeep puts out about 100 volts.