Sizing a UPS (PFC, 80plus)

[bononos]

Whats the reason for a UPS having a much lower wattage rating (~60%) compared to its VA? Would having an apfc, 80plus psu allow for a smaller UPS?

 

[Blain]

Battery storage capacity vs circuit power capacity

 

[imagoon]

Exactly. The inverter rating is the wattage. A 200watt inverter (generally) doesn't care if it is attached to a 1 10vAh battery or 14 10vAh batteries. The same inverter would run 14 x longer than that first one (baring losses and all that) but would never exceed the 200 watt rating no matter how many batteries are piled behind it.

 

[Red Squirrel]

Typically the bigger UPSes will also have bigger batteries which means more run time, so I tend to oversize as much as I feel is reasonable budget wise. The 1000VA (600w actual power) are decently cheap so I usually get that, and they'll run pretty much any machine unless it's like a triple SLI type machine then you probably want a bigger UPS like 1500VA.

Never go by the run time it says on the box. That's assuming the planets are lined up properly and that Jesus Christ himself has blessed the acid that went into making the batteries. You'll get maybe 1/4 of the run time it says on the box. Typically 5-10 minutes at very most on a standard SOHO UPS at half load.

 

[XavierMace]

You'll get maybe 1/4 of the run time it says on the box. Typically 5-10 minutes at very most on a standard SOHO UPS at half load.

Either you don't know how to read the run time ratings of you're buying really crappy UPS's.