# What does 1500VA in a UPS mean?

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jp10558

So, I bought a 1500VA 900W Cyberpower UPS for my room. I think I got a decent deal at \$120 for it. Anyway, I am lazy, and just plugged my surge protector into one of the plugs. In tests I do get the claimed 45 Minutes battery backup.

My question is the load readout in the software. Does anyone know why a 20 inch boxfan would account by itself for ~ 11% of the load - Almost as much as just the PC at ~16% Load. I though box fans were quite energy efficient...

I'm a total n00b when it comes to electricity if you haven't figured it out by now lol.

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gdodson

I think box fans draw a fairly large current, but have a lower voltage.

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OxygenOne

From this page which explains more about UPS devices, it defines VA as:

The VA rating is the maximum number of Volts * Amps a unit can deliver. The VA rating is not the same as the power drain (in Watts) of the equipment. The easiest way to find out how many VA is needed is to look at the back of the equipment that is to be protected and note the total number of amps listed for each device. Take the total and multiply it by the nominal voltage (120V) to get the number of VA.

So a typical 20 inch box fan uses 5 amps let's say - 120 V * 5A = 600VA. This is just an example, and a 420W PC uses 10A for a total of 1200VA. These are of course ficticious numbers since I do not have a box fan sitting around.

Hope this helps

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• 10 years later...
angrynewraze

So how much va would a 860w or 1600w pc use then?

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goatsniffer

The VA (volt-ampere) rating in a UPS is not the same as amperage (A).

Wattage (W) is determined by (voltage * amperage), so to determine amperage (A) draw of your equipment you can divide the wattage draw by the voltage (V) of your current.

For AC current at 120V and wattage draw at 860W, you would be using approximately 7.16A. The VA rating means nothing here.

VA = 1W of DC power (I.E The current in the batteries). So when shopping for a UPS you should consider VA rating as the total potential DC current in the batteries and the wattage rating as the total amount of AC current that the device can convert and supply. A UPS could potentially have 10,000VA rating, but supply it at 50w, you would just have extremely long runtime for low-powered devices.

Edited by goatsniffer
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+BudMan

why in the world would you have a box fan plugged into a ups in the first place??  Is my question..

I would think a typical box fan would draw about a 100 watts..  So yeah seem about right for your 11% on a 900watt ups.

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Jim K

why in the world would you have a box fan plugged into a ups in the first place??  Is my question..

I would think a typical box fan would draw about a 100 watts..  So yeah seem about right for your 11% on a 900watt ups.

Box fan post(s) are from 2005.

http://www.power-solutions.com/watts-va

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+BudMan

heheh - thanks, normally I catch that..  get a mod to lock this..

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Jason S.

good catch guys. im going to go ahead and lock the thread.

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• Jason S. locked this topic
This topic is now closed to further replies.