XS 1500 Watt Usage?

[BillP]

I have several Back-UPS XS 1500's and all of them show a wattage usage about 50 Watts below what is actually being used per my Kill-A-Watt measuring device. I have checked the Kill-A-Watt device accuracy using a 25W, 40W, 75W,100W and a 150W bulb and it is only +/- a Watt or so off what the stated bulb wattage. Also, the,wattage indicated by the Kill-A-Watt device is about what I would expect for the computers connected to the Back-UPS's. Is this normal - is APC trying to make the user feel better by understating the amount of electricity being used - or am I missing something?

Message was edited by: Ken429

[BillP]

The UPS should give you an accurate reading of wattage although there is usually a +/- of accuracy when it comes to our measurements. I would say if the difference is significant, you may want to call tech support for your area and see if it might be a problem but unfortunately, I wouldn't say your results are abnormal.

[voidstar_apc]

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Like I said in the first posting, the Kill-A-Watt device appears to be very accurate and the watt usage reported by the Kill-A-Watt device is about what I would expect the PC's to be using. Why can't the APC devices get it right?
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The Kill-A-Watt's job in life is measuring loads so I would expect it to be very accurate. The UPS's main use of load measurement is to detect overload and calculate runtime. If the accuracy isn't sufficient, calling tech support is the best bet.

[BillP]

I don't understand your response! I have three XS 1500 UPS's all bought at different times and connected to three different PC's and they all report a wattage usage that is ~50 watts less that what is actually being used/reported by a Kill-A-Watt device. Like I said in the first posting, the Kill-A-Watt device appears to be very accurate and the watt usage reported by the Kill-A-Watt device is about what I would expect the PC's to be using. Why can't the APC devices get it right?

[BillP]

After calling Technical Support and getting a link suggesting I should go buy a better tester I discovered by accident that the UPS is only reporting wattage usage from the battery backup plugs. I know, that little fact is stated clearly in the manual and help pages! That makes some sense since the UPS's main objective is to calculate the amount of time the battery can run the system. However, the software makes you think it is keeping track of total usage unless of course you go read the help information. Problem solved.

[voidstar_apc · Accepted solution]

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However, the software makes you think it is keeping track of total usage unless of course you go read the help information. Problem solved.
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You're right, that is misleading. Expecting "Total Load" to include the surge-only outlets was a reasonable assumption. I'll see if I can make a bit of noise with the software group.