Bob, All standard residential utility meters read out in kilowatt hours. That is the basis for their tarrifs and billing. You are charged on the actual kilowatt hour use. The ups reading lower on actual battery operation MAY mean the charger is disabled and all you are seeing is magnetizing current of the step down transformer in the charger. You pay for actual usage. So yes it is costing you money to have the unit on line. The bottom line is how much is it costing you per KWH. Your utility has filed and is authorized to charge under their approved tarrifs. Unless you are subject to ratcheting demand charges it is calculated in actual "blocks" or steps. They begin with a modest block at the highest rate per KWH and proceed to biggest "block" at cheaper costs per KWH. The higher the usage the less you pay per KWH until you reach the last and cheapest block. However, remember that this is all cumulative and each time that little disk goes around you can hear the bell on the cash register ring!
Bob M. wrote: > I have an APC SU2200 (SmartUPS, 2200VA) 3U tall, that I put new batteries in > a few months ago. So far it's just sitting, plugged in, turned off, with no > load. I got curious as to how much power it was sucking out of the wall > outlet, so I plugged the UPS into my Kill-A-Watt device and plugged that into > the wall. Here are the numbers I observed: > > 122.2 Volts > 1.48 Amps > 31 Watts > 181 Volt-Amps > 0.17 Power Factor > > The values were identical with the unit turned on, also with no load. The > only thing running inside the UPS is the battery charger; the inverter is > completely bypassed and is not running. > > I then ran the UPS into a test cycle, again with no load, but this time the > inverter turned on and powered the load, thus disconnecting itself from the > commercial AC power. Surprisingly, there was still a little bit of power > being used, probably by the transformer and line sampling circuit. Here are > the readings I got during the self-test: > > 122.4 Volts > 0.09 Amps > 0 Watts > 11 Volt-Amps > 0.06 Power Factor > > As far as I know, the utility's kilowatt-hour meter on the side of my house, > which is a rotating aluminum-disc style, measures WATTS, not Volt-Amps. > Somehow APC has managed to get their charging circuit to draw a lot of > current while keeping the power factor and Wattage power extremely low. I > suspect it's highly capacitive. > > So here's where you all get to jump in. Is this UPS costing me a lot just to > keep the batteries charged (180 VA) or am I only being charged for the > wattage it draws? > > Bob M. > > > > > ------------------------------------ > > > > Yahoo! Groups Links > > > >
