On Tue, May 29, 2007 at 02:55:02PM -0400, Jim Perrin wrote: > On 5/29/07, Mark Hull-Richter <mhullrich at gmail.com> wrote: > > >Getting a little OT here, but how does one match up the VA ratings of > >the UPSs (and battery backups) with the power supply wattage ratings? > > Watts = Volts x Amps. I usually use a sliding scale based on # of machines. Which is correct for DC circuits, but not for AC. A 1500VA UPS does not provide 1500Watts of power. And given the output of UPS's aren't necessarily perfect sine waves, it gets more complicated. A typical APC 1500VA UPS has around 860->900Watts of power. The answer to Mark's question is "check the manufacturers web site" :-) -- rgds Stephen