[Park Seward]

A UPS wil last longer the more capacity it has. If you just need a few minutes of charge, a small unit will be fine, If you want it to run for an hour, you need a much bigger unit. Most units will have a chart showing the runtime vs. load.

At 500 watts, this unit will run for only five minutes and it can't take more than 500 watts. I'd get a bigger unit. At minimum, I'd get the SMT1000.

How do I know? I did a Google search.

http://www.apc.com/products/resource...e&list=SMT750;


Converting VA to Amps (voltage fixed)

The conversion of VA to Amps is governed by the equation Amps = VA·PF/Volts)

For example 12 VA·0.6/(12 volts) = 0.6 amp

Converting KVA to KW (Kilovolt-amps to Kilowatts)

The conversion of KVA to KW is governed by the equation KVA = KW/PF)

For example, if the power factor is 0.6
120 KVA·0.6 = 72 Kilowatts

Converting Watts to KVA (watts to kilovolt-amps)

The conversion of W to KVA is governed by the equation KVA=W/(1000*PF)


For example 1500W/(1000*0.83) = 1.8 kVA (assuming a power factor of 0.83)
F
Converting Amps to VA (voltage fixed)

The conversion of Amps to VA is governed by the equation VA = Amps · Volts/PF

For example 1 amp * 110 volts/0.6 = 183 VA

http://www.powerstream.com/VA-Watts.htm